Activated protein C attenuates intestinal reperfusion-induced acute lung injury: an experimental study in a rat model

BACKGROUND: Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. APC has been shown to attenuate local deleterious effects of ischemia/reperfusion (I/R) injury in many organs. We aimed to investigate the effects of APC on lung reperfusion injury induced by superior mesenteric occlusion. METHODS: Male Wistar-Albino rats were allocated into 4 groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to group 1 except for APC treatment (n = 12); (3) intestinal I/R group, 60 minutes of ischemia followed by 3 hours of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 microg/kg injection of APC intravenously, 15 minutes before reperfusion (n = 12). Evans blue dye was injected into half of the rats in all groups. We assessed the degree of pulmonary tissue injury by measuring activities of oxidative and antioxidative enzymes, as well as nitrate (NO(3)(-))/nitrite (NO(2)(-)) levels, biochemically. We evaluated acute lung injury (ALI) by establishing pulmonary neutrophil sequestration and ALI scoring histopathologically. Pulmonary edema was estimated by using Evans blue dye extravasation and wet/dry ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. RESULTS: APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the lung tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes (P < .05). Pulmonary neutrophil sequestration and ALI scores were decreased significantly with APC administration (P < .05). In addition, APC treatment significantly alleviated pulmonary edema (P < .05). CONCLUSIONS: This study clearly showed that APC treatment significantly attenuated the lung reperfusion injury. Further clinical studies are required to clarify whether APC has a useful role in the reperfusion injury during particular surgeries in which I/R-induced organ injury occurs.     

Role of Activated Protein C on Wound Healing Process in Left Colonic Anastomoses in the Presence of Intra-abdominal Sepsis Induced by Cecal Ligation and Puncture: An Experimental Study in the Rat

Background  Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. The delaying effects of intra-abdominal sepsis on wound healing process in colonic anastomoses have been previously demonstrated. This study was designed to investigate the role of APC on wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis. Methods  The left colonic anastomosis was performed in 48 rats that were divided into four groups: (1) sham-operated group, laparatomy plus cecal mobilization (n = 12); (2) sham + APC group, identical to group I except for APC treatment (n = 12); (3) CLP group, cecal ligation and puncture (n = 12); 4) CLP + APC-treated group, 100 μg/kg, 15 min before the construction of colonic anastomosis (n = 12). Anastomotic bursting pressures were measured in vivo on day 7. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) acivity, malondialdehyde (MDA), and nitrate/nitrite (NO₃⁻/NO₂⁻) levels. The plasma levels of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and D-dimer also were measured. Results  Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures and tissue HP contents, along with increases in MPO activity, MDA and NO₃⁻/NO₂⁻ levels, and also plasma levels of TNF-α, IL-6, and D-dimer (P < 0.05). However, APC treatment led to significant increases in anastomotic bursting pressures and tissue HP ontents, along with decreases in MPO activity, MDA and NO₃⁻/NO₂⁻ levels, and also plasma levels of TNF-α, IL-6, and D-dimer (P < 0.05). Conclusions  This study clearly showed that APC treatment prevented the delaying effects of intra-abdominal sepsis on colonic anastomotic wound healing process. Further clinical studies are required to determine whether APC has a useful role in the enhancement of anastomotic healing during particular surgeries in which sepsis-induced injury occurs.     

The Effects of Simvastatin on Ischemia Reperfusion Injury in an Experimental Colon Anastomosis Model

Anastomotic leakage is more frequently reported in colonic anastomoses. Ischemia reperfusion injury is one of the main reasons for anastomotic leakage. Simvastatin is known to prevent tissue damage induced by free oxygen radicals after ischemia reperfusion injury. The effect of simvastatin on colonic anastomosis impaired by ischemia reperfusion injury is investigated. Single layer, end-to-end colocolic anastomosis after 0.5-cm colon resection was performed in Wistar Albino rats. In Group 1 (control) (n?=?10), colonic anastomosis without I-R was performed. In Group 2 (n?=?10), the superior mesenteric artery was clamped for 10 min followed by 60 min of reperfusion after which resection anastomosis was performed. In Group 3 (n?=?10), 10 mg/kg simvastatin was given by gavage for 7 days after I-R and resection anastomosis. In Group 4 (n?=?10), the rats received 10 mg/kg simvastatin by gavage 7 days before and 7 days after ischemia reperfusion and surgery. All of the rats were sacrificed 8 days after surgery. Anastomotic bursting pressure and tissue hydroxyproline levels were measured. Postoperative administration of simvastatin restored the anastomotic bursting pressure and hydroxyproline levels to that of control group thus overcoming the effect of ischemia reperfusion injury. Simvastatin administered postoperatively in an experimental model of colonic resection anastomosis impaired by ischemia reperfusion injury increased anastomotic bursting pressures and tissue hydroxyproline levels. Further experimental and clinical studies will show whether administration of simvastatin will increase reliability of the anastomosis and decrease postoperative morbidity and mortality in colonic anastomosis after ischemia reperfusion injury.     

Protection of colonic anastomosis with platelet-rich plasma gel in the open abdomen

Background

Although evidence for colonic anastomosis in the damage control abdomen continues to accumulate, anastomotic leak is common and associated with greater morbidity. The purposes of our study was to evaluate the effect of platelet-rich plasma (PRP) gel on the healing of colon anastomosis and anastomotic strength in the open abdomen.

Methods

PRP was prepared by enriching whole blood platelet concentration from healthy rat. In the rodent model, standard colonic anastomoses followed by closure of abdomen (Control; n = 10) and anastomoses followed by open abdomen (OA; n = 10) were compared to PRP-sealed anastomoses in open abdomen (OA + PRP; n = 10). One week after surgery, body weight, anastomotic bursting pressure, hydroxyproline concentration, and histology of anastomotic tissue were evaluated.

Results

All rats survived surgery and had no signs of anastomotic leakage. Compared with the control and PRP group, OA group exhibited a significant decrease in body weight, anastomotic bursting pressure, hydroxyproline concentration, and collagen deposition. No significant difference was detected in these variables between the PRP group and the control group.

Conclusion

PRP gel application prevented delayed anastomotic wound healing after open abdomen, which suggested that anastomotic sealing with PRP gel might improve outcome of colonic injuries in the setting of open abdomen.     

Hydroxyethyl starch 130/0.4 augments healing of colonic anastomosis in a rat model of peritonitis

Background

This study was designed to investigate the role of hydroxyethyl starch (HES) 130/0.4 on the wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis.

Methods

The left colonic anastomosis was performed in 40 rats that were divided into 4 groups: (1) group SHAM, laparatomy plus cecal mobilization (n = 10); (2) group SHAM + HES, HES130/.4-treated controls (n = 10); and (3) group CLP, cecal ligation and puncture (n = 10); (4) group CLP + HES, CLP plus HES130/.4 (n = 10). HES130/.4 was administrated before the construction of colonic anastomosis, 15 mL/kg/24 hours and daily for 4 postoperative days. Anastomotic bursting pressures (ABPs) were measured in vivo on day 5. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) activity, malondialdehyde (MDA), reduced glutathione (GSH) levels, and nuclear factor-κB (NF-κB) activation. The plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, d-dimer, and protein C (PC) were also measured. Anastomotic granulation tissues were fixed for transmission electron microscopic (TEM) analyses.

Results

Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures, perianastomotic tissue HP contents, GSH levels, and plasma levels of PC, along with increases in perianastomotic tissue MPO activity, MDA levels, NF-κB activation, and plasma levels of TNF-α, IL-6, and d-dimer. However, HES130/.4 treatment significantly inhibited all these responses. TEM analyses revealed that there was a trend toward a higher density of fibroblast distribution and a higher rate of fibroblast activation in the SHAM- and HES 130/0.4-treated animals, compared with the CLP group.

Conclusions

This study showed that moderate doses (15 mL/kg) of HES 130/0.4 administration significantly prevented this intraperitoneal sepsis-induced impaired anastomotic healing of the left colon. This beneficial effect of HES 130/0.4 can be mainly attributed to its anti-inflammatory and antioxidant properties and beneficial effects of modulating endothelial-associated coagulopathy.     

Comparison of early postoperative enteral nutrients versus chow on colonic anastomotic healing in normal animals

We aimed to clarify the effects of different enteral nutrients (normal chow, complete balanced nutrition, elemental nutrition enriched with glutamine, immune-enhancing diet and fiber) on colonic anastomotic healing in the stress-free metabolic state. The study was carried out with 50 male Balb-C mice in five groups of 10 animals each. After transverse colon anastomosis, animals were fed with early enteral nutrients using normal chow (group 1), Ensure((R)) (group 2), Alitraq((R)) (group 3), Impact((R)) (group 4), and Benefiber Resource((R)) orange juice drink (group 5) for 7 days. There were no significant differences among the groups in bursting pressure (p > 0.05). There was no statistical difference in terms of hydroxyproline level among groups 1-3. The hydroxyproline levels of groups 4 and 5 were statistically higher than that of the control group (p < 0.05 for both comparisons). Under normal conditions without stress, we could not demonstrate the superior effects of early enteral feeding with specialized enteral preparations over normal diets on colonic anastomoses when the bursting pressures were compared.     

The effects of iloprost on colonic anastomotic healing in rats under obstructive ileus conditions

Background

The aim of this study was to investigate the effects of iloprost, on colonic anastomotic healing in rats, under obstructive ileus conditions.

Materials and methods

Eighty male Albino rats were randomized into four groups of 20 animals each. They underwent colonic resection followed by an inverted anastomosis. The rats of group 1 (control) and group 2 (ileus) received 3 mL of saline 0.9% intraperitoneally and those of group 3 (iloprost), and group 4 (ileus + iloprost) iloprost (2 μg/kg of body weight), immediately postoperatively and daily until the day of sacrifice. Each group was further divided into two equal subgroups, depending on the day of sacrifice. The animals of subgroup “a” were sacrificed on the fourth postoperative day, whereas those of “b” on the eighth day. Macroscopic and histologic assessment was performed, whereas anastomotic bursting pressures and the tissue concentrations in hydroxyproline and collagenase I were evaluated.

Results

Means of bursting pressure, neoangiogenesis, fibroblast activity, and hydroxyproline concentration were significantly increased in group 4 compared with group 2. In addition, on the fourth postoperative day, the inflammatory cell infiltration and the collagenase I concentration were significantly decreased in group 4 compared with group 2. Moreover, on the eighth postoperative day, collagen deposition was significantly increased in group 4 compared with group 2.

Conclusions

Iloprost after intraperitoneal administration reverses the negative effect of obstructive ileus. It promotes not only the angiogenic activity but also collagen formation, resulting in increased bursting pressures on the fourth and eighth postoperative days.     

Effects of trapidil on the healing of colonic anastomoses in an experimental rat model

Background: Trapidil has various properties including vasodilatation, inhibition of lipid peroxidation and platelet aggregation as well as, and reduction of, the inflammatory response to injury. The aim of the present study was to investigate the effects of trapidil on dexamethasone‐impaired colonic anastomotic healing in an experimental rat model. Methods: Twenty‐four Wistar rats underwent colonic transsection and primary anastomosis. Rats were divided into four groups of six: group 1 (G1), control; group 2 (G2) trapidil, 8 mg/kg per day intravenously; group 3 (G3) dexamethasone, 0.1 mg/kg per day intramuscularly; and group 4 (G4) dexamethasone 0.1 mg/kg intramuscularly and trapidil 8 mg/kg intravenously per day, for 1 week. Anastomotic bursting pressure, hydroxyproline level, histopathological grading, malondialdehyde and nitrite/nitrate levels were determined. Results: Dexamethasone‐impaired anastomotic healing was found to be improved by trapidil administration in terms of anastomotic bursting pressure and hydroxyproline content (P = 0.026, and P = 0.017). In addition, histopathological examination revealed an increase in fibroblast proliferation and collagen deposition (P = 0.004, and P = 0.015) and a decrease in leucocyte infiltration (P = 0.004). Moreover, serum nitrite/nitrate and malondialdehyde levels decreased when G3 was compared to G4 (P < 0.001, P= 0.38). Conclusions: Trapidil may improve the dexamethasone‐impaired anastomotic healing due to its preventive effects on inflammatory response and lipid peroxidation in rats.     

Pyrrolidine Dithiocarbamate Prevents Deleterious Effects of Remote Ischemia/Reperfusion Injury on Healing of Colonic Anastomoses in Rats

Background Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, a delaying effect of remote organ I/R injury on the healing of colonic anastomoses has been demonstrated. In this study we investigated whether PDTC prevents harmful systemic effects of superior mesenteric I/R on left colonic anastomosis in rats. Methods Anastomosis of the left colon was performed in 40 rats randomly allocated into the following four groups: (1) Sham-operated group (group I, n = 10)—simultaneously with colonic anastomosis, the superior mesenteric artery and collateral branches divided from the celiac axis and the inferior mesenteric artery were isolated but not occluded. (2) Sham+PDTC group (group II, n = 10)—identical to sham-operated rats except for the administration of PDTC (100 mg/kg IV bolus) 30 minutes prior to commencing the experimental period. (3) I/R group (group III, n = 10)—60 minutes of intestinal I/R by superior mesenteric artery occlusion. (4) PDTC-treated group (group IV, n = 10)—PDTC 100 mg/kg before and after the I/R. On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for investigation of anastomotic hydroxyproline (HP) contents, perianastomotic malondialdehyde (MDA) levels, myeloperoxidase activity (MPO), and glutathione (GSH) level. Results There was a statistically significant decrease in anastomotic bursting pressure values, tissue HP content and GSH level, along with an increase in MDA level and MPO activity in group III, when compared to groups I, II, and IV (p < 0.05). However, PDTC treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP content and GSH level, along with a decrease in MDA level and MPO activity in group IV (p < 0.05). Conclusions This study showed that PDTC treatment significantly prevented the delaying effect of remote organ I/R injury on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent for increasing the safety of the anastomosis during particular operations where remote organ I/R injury occurs.     

The effect of remote ischemic preconditioning on healing of colonic anastomoses

BACKGROUND: We aimed to investigate the potential protective effect of remote ischemic preconditioning (IPC) on delayed colonic anastomotic healing induced by remote ischemia and reperfusion (I/R) injury. MATERIALS AND METHODS: Forty male Wistar rats were randomly assigned into four groups, each consisting of 10 rats: the control group (C), the remote I/R group [I/R, 40 min of superior mesenteric artery (SMA) occlusion], the preconditioned I/R group (IPC, two cycles of 5 min temporary occlusion of SMA before an ischemic insult of 40 min), and the preconditioned group (PC, two cycles of 5 min temporary occlusion of SMA). Colonic anastomosis was performed immediately after the ischemic insult. Anastomotic healing was assessed on postoperative day 7 by determining anastomotic bursting pressure (ABP), tissue hydroxyproline content, histopathological examination, malondialdehyde (MDA), and nitric oxide levels. RESULTS: Remote I/R injury resulted with significant impairment in anastomotic healing in terms of mean ABP (P = 0.004), hydroxyproline content (P = 0.002), histopathological healing score (P = 0.001), nitric oxide level (P = 0.010), and MDA levels (P = 0.0001) when compared with the control group, but remote IPC did not improve all above mentioned parameters (P = NS for all), except MDA level (P = 0.011) when compared with I/R group. PC alone impaired the ABP (P = 0.0001), but it did not significantly change the other parameters measured (P = NS). CONCLUSIONS: The results of this study showed that remote IPC did not prevent I/R-induced delaying in colonic anastomotic healing.     

The effects of local and sustained release of fibroblast growth factor on wound healing in esophageal anastomoses

Background/Purpose

Postsurgical complications, such as anastomotic leaks in patients with esophageal atresia, have remained unchanged during the last 3 decades. Growth factors enhance healing in several wound-healing models. Therefore, an experimental study was used to evaluate the effects of local and sustained release of basic fibroblast growth factor (FGF) on wound healing in esophageal anastomoses.

Materials and Methods

Twenty-four male Wistar albino rats, which were subjected to a 1-cm segmental resection of the abdominal esophagus followed by end-to-end anastomosis, were allocated into 3 groups. Group I, the control group, had no gelatin film applied to the anastomosis. In group II (gelatin film without FGF) and group III (gelatin film with FGF), anastomoses were covered with unloaded and 2.55 μg FGF-loaded gelatin films, respectively. On postoperative day 7, bursting pressures, histopathologic collagen deposition, and tissue hydroxyproline concentrations of the anastomoses were then analyzed and compared.

Results

Mean bursting pressures, mean submucosal and muscular collagen deposition scores, and mean tissue hydroxyproline concentrations differed significantly between groups. Mean bursting pressures were 22.5 ± 3.1 mm Hg in group I, 29 ± 1.6 mm Hg in group II, and 63.2 ± 6.8 mm Hg in group III (P < .001). Mean submucosal collagen deposition scores (group I: 0.7 ± 0.2, group II: 0.7 ± 0.1, group III: 1.5 ± 0.2; P = .02) and mean muscular collagen deposition scores (group I: 0.8 ± 0.2, group II: 0.8 ± 0.1, group III: 1.8 ± 0.1; P = .01) were significantly higher in FGF animals than the other in the other 2 groups. Mean tissue hydroxyproline concentrations were 2.4 ± 0.5 μg/mg in group I, 3.9 ± 0.4 μg/mg in group II, and 6.0 ± 1.0 μg/mg in group III (P = .007).

Conclusion

Local and sustained release of FGF enhanced wound healing in esophageal anastomoses in this animal model.     

Effects of Pyrrolidine Dithiocarbamate on Healing of Colonic Anastomoses in the Cecal Ligation and Puncture Model of Intraperitoneal Sepsis in Rats

Introduction Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. In recent animal studies, the delaying effect of intraperitoneal sepsis on healing of colonic anastomoses has been demonstrated. In this study, we aimed to investigate the effects of PDTC on healing of colonic anastomoses in the presence of intraperitoneal sepsis induced by a rodent model of cecal ligation and puncture (CLP). Methods Anastomosis of the left colon was performed on the day following CLP in 30 rats that were divided into three groups: sham-operated control (laparotomy and cecal mobilization, group I, n =10), cecal ligation and puncture (CLP) (group II, n = 10), PDTC-treated group (100 mg/kg IV before construction of the colonic anastomosis) (group III, n = 10). On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of colonic anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, and malondialdehyde (MDA) and glutathione (GSH) levels. Results There was a statistically significant increase in the activity of MPO and MDA levels in the CLP group (group II) along with a decrease in GSH levels, colonic anastomotic HP contents, and bursting pressure values when compared to controls (group I). However, PDTC treatment led to a statistically significant increase in the tissue HP contents, GSH levels, and colonic anastomotic bursting pressure values, along with a decrease in MPO activity and MDA levels in group III (p < 0.05). Conclusions This study showed that PDTC treatment significantly prevented the delaying effect of CLP-induced intraperitoneal sepsis on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to increase the safety of the anastomosis during particular operations where sepsis-induced injury occurs.     

Pinealectomy Does Not Affect the Healing of Experimental Colonic Anastomoses

Gastrointestinal system anastomoses, especially colonic anastomoses, have significant morbidity and mortality despite recent technical improvements. Besides regulating the circadian rhythm, the pineal gland and its main neurohormone product melatonin have widespread actions in the organism. The purpose of this study was to investigate the effects of pinealectomy on the healing of colonic anastomoses. One hundred male albino Wistar rats were used in this study. The rats were separated into three groups: control, pinealectomy, and sham groups. In the control group, only colonic resection and anastomoses were performed. Following pinealectomy, colonic anastomosis was performed 2 weeks later on one half and 2 months later on the other half of the pinealectomy group. Only craniotomy was performed on the sham group, and the rats were separated and evaluated like the pinealectomy group. Colonic anastomoses were evaluated on postanastomotic day 3 and 7 by measuring the bursting pressure and the hydroxyproline levels in the anastomotic segments. There was no difference in the bursting pressure measurements between the groups on both postoperative day 3 and 7. Although hydroxyproline levels were different between groups on both postanastomotic days 3 and 7, it has been observed that neither normal nor anastomotic hydroxyproline levels influenced the anastomotic bursting pressure measurements. The percent deviation from the normal values was compared in the anastomotic segments, and no differences were found regarding the bursting pressure and hydroxyproline levels. It was concluded that pinealectomy has no effect on the healing of colonic anastomoses.     

Effects of portal triad occlusion on left-sided colonic anastomosis

Anastomotic healing can deteriorate because of different local and systemic effects in cases of concomitant left colon and liver injuries. We evaluated the effects of portal triad occlusion (PTO) on bowel anastomosis after concomitant segmental left colonic resections achieved in rats. There were three separate groups of animals; each consisted of 20 Sprague-Dawley male rats weighing 250 +/- 20 g. In group I, left colonic segmental resection 1 cm in diameter and anastomosis were performed as controls. In group II, the same surgical procedure was done after 15 minutes of PTO followed by 30 minutes of reperfusion. In group III, PTO time was held at 30 minutes. The rats were killed at days 4 and 7 to evaluate anastomotic healing, histological changes, bursting pressures, and serum levels of malondialdehyde (MDA) and hydroxyproline. In group II, the bursting pressures of anastomosis on days 4 and 7 were similar to group I; these pressures were significantly lower in group III (P < 0.001), whereas the hydroxyproline levels in group II were lower than group I and group III levels (P < 0.002). There were histopathological changes that support the data found in groups II and III. Serum MDA levels in groups II and III were significantly higher than in group I (P < 0.001). We observed that serum MDA levels peaked at day 4 and gradually decreased with a statistically significant difference at day 7. In conclusion, there were no negative effects of PTO on colonic anastomosis in group II. But in group III, with longer occlusion times, anastomotic healing was impaired and the mortality rate was higher.     

Pinealectomy does not affect the healing of experimental colonic anastomoses.

Gastrointestinal system anastomoses, especially colonic anastomoses, have significant morbidity and mortality despite recent technical improvements. Besides regulating the circadian rhythm, the pineal gland and its main neurohormone product melatonin have widespread actions in the organism. The purpose of this study was to investigate the effects of pinealectomy on the healing of colonic anastomoses. One hundred male albino Wistar rats were used in this study. The rats were separated into three groups: control, pinealectomy, and sham groups. In the control group, only colonic resection and anastomoses were performed. Following pinealectomy, colonic anastomosis was performed 2 weeks later on one half and 2 months later on the other half of the pinealectomy group. Only craniotomy was performed on the sham group, and the rats were separated and evaluated like the pinealectomy group. Colonic anastomoses were evaluated on postanastomotic day 3 and 7 by measuring the bursting pressure and the hydroxyproline levels in the anastomotic segments. There was no difference in the bursting pressure measurements between the groups on both postoperative day 3 and 7. Although hydroxyproline levels were different between groups on both postanastomotic days 3 and 7, it has been observed that neither normal nor anastomotic hydroxyproline levels influenced the anastomotic bursting pressure measurements. The percent deviation from the normal values was compared in the anastomotic segments, and no differences were found regarding the bursting pressure and hydroxyproline levels. It was concluded that pinealectomy has no effect on the healing of colonic anastomoses.     

Locally applied molgramostim improves wound healing at colonic anastomoses in rats after ligation of the common bile duct.

BACKGROUND: Several systemic factors, including jaundice, long-term corticosteroid therapy, diabetes and malnutrition, increase the risk of anastomotic dehiscence. The local application of molgramostim (recombinant human granulocyte-macrophage colony stimulating factor) has been reported to improve impaired dermal wound healing. Since jaundice, one of the systemic risk factors for anastomotic dehiscence, causes significant impairment of anastomotic healing, we hypothesized that locally injected molgramostim could improve the healing of bowel anastomoses in bile-duct-ligated rats used as an experimental model for jaundice. METHODS: Eighty-six Sprague-Dawley rats were randomized into 4 groups of 20-22 animals each as follows: group 1--colonic anastomosis only; group 2--laparotomy followed 7 days later by colonic anastomosis; group 3--common-bile-duct ligation (CBDL) followed 7 days later by colonic anastomosis (control group); group 4--CBDL followed by colonic anastomosis with locally applied molgramostim. Laparotomy was performed under anesthesia in group 2 rats. In groups 3 and 4, laparotomy was followed by ligation and dissection of the common bile duct. After 7 days, colonic anastomosis was performed; in group 4 rats, molgramostim (50 microg) was injected into the perianastomotic area. On postoperative day 3, rats were killed, and the bursting pressures and hydroxyproline levels measured. Two rats from each group were selected for histopathological examination. RESULTS: The mean bursting pressure in group 4 was significantly higher than that in group 3 (37.8 v. 30.5 mm Hg [p < 0.01]). The mean hydroxyproline level in group 3 was significantly lower than that of the other groups (2.7 v. 3.1-3.5 mg/g tissue [p < 0.01]). On histopathological examination, specimens from group 4 rats showed an increased mononuclear cell population and a smaller gap on the anastomotic line than those from group 3. CONCLUSION: The local injection of molgramostim improves healing of the impaired wound in rats subjected to CBDL.     

Protective effect of erythropoietin pretreatment in testicular ischemia-reperfusion injury in rats

Background/Purpose

This study was designed to investigate the effects of recombinant erythropoietin (EPO), a hormone widely used for treatment of uremic anemia, in rats subjected to testicular ischemia and reperfusion (I/R).

Methods

Thirty-five male rats were divided into the following: control, sham operated, ischemia (I), I/R, and I/R + EPO groups. In the I group, 2 hours of left unilateral testicular torsion were performed, and in the I/R and I/R + EPO groups, an additional 2 hours of testicular detorsions were performed. The I/R + EPO group was pretreated intraperitoneally with EPO (500 IU/kg) before reperfusion. Testicular tissue samples were examined for biochemical and histopathologic parameters. Apoptotic cells in all testes were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling technique and caspase 3 immunohistochemistry.

Results

At histopathologic examination, ischemic changes in primary spermatocytes were noted in all torted testes. Cellular damage and apoptosis were more severe in ischemic groups than the EPO-pretreated group. There were statistically significant differences in tissue biochemical parameters in the I and I/R groups compared with the I/R + EPO group.

Conclusions

The results of the present study suggest that EPO exerts protective effects against I/R injury via the modulation of free radical scavenger's activities, which decreases lipid peroxidation levels and attenuation of apoptosis.     

Modulation of the Reaction of Vascular Smooth Muscle Cells to Angiotensin II Induced by Catalase and Aminotriasol During Ischemia-Reperfusion

Background

We investigated the influence of catalase and aminotriasol on reactions of the smooth muscle cells induced by angiotensin II (ANG II) after ischemia-reperfusion (I/R).

Materials and Methods

Experiments were performed on perfused male Wistar rat tail arteries. Using classical pharmacometric methods we analyzed the influence of ANG II on vascular contraction, in the presence of catalase and aminotriazole, and after I/R.

Results

A reduction in maximal response and increased EC₅ value were observed after ischemia, while an increased maximal response and decrease EC₅₀ value were observed after reperfusion. Catalase decreased and aminotriasol increased maximal responses to ANG II. In the presence of catalase, reduction of the maximal response and increase in EC₅₀ value were observed after reperfusion. In the presence of aminotriasol, we observed increased maximal response and decreased EC₅₀ value after I/R.

Conclusion

Ischemia reduced and reperfusion increased the responses of vascular smooth muscle cells to ANG II. Catalase decreased and aminotriasol increased hyperreactivity of arteries to ANG II after reperfusion. These results suggested that antioxidative system modulates reactions induced by ANG II. Reperfusion impairs the balance between antioxidants and the production of reactive oxygen species.     

Effects of montelukast on the healing of ischemic colon anastomoses

Background

The aim of this study was to examine whether treatment with montelukast, a selective leukotriene antagonist, would affect anastomotic healing in a reperfused colon rat model with remote ischemia/reperfusion injury.

Methods

Rats (n = 12 per group) were intraperitoneally administered normal saline or 10 mg/kg montelukast sodium 60 minutes before and for 5 days after surgery. Ischemia was induced for 45 minutes through superior mesenteric artery occlusion. A left colon anastomosis was made. Blood and perianastomotic tissue samples were obtained on postoperative day 5.

Results

Mean anastomotic bursting pressures of the control and montelukast groups were 159.17 ± 29.99 and 216.67 ± 26.40, respectively (P < .001). Compared with saline, montelukast treatment increased the mean tissue hydroxyproline level (2.46 ± .30 vs 3.61 ± .33 μmol/L) and decreased tissue caspase-3 activity (36.06 ± 5.72 vs 21.78 ± 3.87) and malondialdehyde levels (3.43 ± .34 vs 2.29 ± .34 nmol/g) (P < .001 for all). Other plasma markers of injury also showed differences.

Conclusions

Montelukast prevented ischemia/reperfusion-induced damage in a rat model of colonic anastomotic wound healing.     

Protective effect of tadalafil on ischemia/reperfusion injury of rat ovary

Background/Purpose

The aim of the study was to evaluate the effects of tadalafil (TDF) on ischemia/reperfusion (I/R) injury in rat ovaries.

Methods

Thirty-five female Sprague-Dawley rats were randomly divided into 5 groups (n = 7): sham (S), I/R1, I/R2, TDF1, and TDF2. In the I/R1 and TDF1 groups, 3-hour ischemia was followed by 12-hour reperfusion; and in the I/R2 and TDF2 groups, 3-hour ischemia was followed by 24-hour reperfusion. In the TDF groups, 30 minutes before reperfusion, a single dose of 5 mg/kg TDF was administered intraperitoneally. The ovarian tissue levels of malondialdehyde and nitric oxide (NO), and the activities of superoxide dismutase and catalase were measured biochemically. Tissue damage to ovarian tissue was scored by histopathologic examination.

Results

The tissue malondialdehyde levels were significantly higher and the catalase and superoxide dismutase activities were significantly lower in the I/R groups compared with the S and TDF groups (P < .05). The NO levels were significantly higher in the TDF1 group than the S and I/R1 groups (P < .05). Although the NO levels were increased in the TDF2 group compared with the I/R2 group, the difference was not significant. Ovarian tissue damage scores of the I/R groups were significantly higher than those of the S group (P < .05). Treatment with TDF significantly decreased the ovarian tissue damage scores in the TDF groups compared with the I/R groups (P < .05).

Conclusions

Tadalafil is effective in preventing tissue damage induced by I/R in rat ovaries.