Circulating CXC-chemokine concentrations in a murine intestinal ischemia-reperfusion model

BACKGROUND: CXC-chemokines bearing the glutamic acid-leucine-arginine (ELR) motif (ELR+ CXC chemokines) are potent neutrophil chemoattractants and hence may play a role in mucosal injury seen with intestinal ischemia-reperfusion (I/R). METHODS: Serum concentrations of ELR+ CXC chemokines (keratinocyte-derived chemokine(KC) / CXC ligand (CXCL) 1, macrophage inflammatory protein (MIP)-2/CXCL 2/3, lipopolysaccharide-induced CXC chemokine (LIX) / CXCL5, and lungkine/CXCL15) were measured in a murine intestinal I/R model. Fifteen 4-week-old wild-type mice were studied in three subgroups: sham, ischemia (superior mesenteric artery [SMA] clamping for 60 min) and ischemia-reperfusion (SMA clamping for 60 min followed by reperfusion for 90 min). RESULTS: Concentrations of KC/CXCL1 and MIP-2/CXCL2/3 in sham-treated animals (145 +/- 123 and 107 +/- 55 pg/mL, respectively) and the ischemia subgroup (646 +/- 413 and 226 +/- 129 pg/mL) were similar, but concentrations were signifcantly higher with reperfusion (6398 +/- 2297, p < .001 and 874 +/- 790 pg/mL, p = .04). LIX/CXCL5 and lungkine/CXCL15 concentrations did not change significantly with ischemia or following I/R. KC/CXCL1 and MIP-2/CXCL2/3 concentrations correlated positively with the severity of mucosal injury and with each other, whereas a negative relationship was observed between LIX/CXCL5 concentrations and microscopic injury scores. CONCLUSIONS: Development of mucosal injury in intestinal I/R is associated with increased serum concentrations of KC/CXCL1 and MIP-2/CXCL2/3, but not with those of LIX/CXCL5 and lungkine/CXCL15.     

Dual roles of commensal bacteria after intestinal ischemia and reperfusion

The roles of commensal bacteria after intestinal ischemia and reperfusion (IIR) are unclear. In current study, we aim to investigate the effects and underlying mechanisms of commensal bacteria in injury and epithelial restitution after IIR. Commensal gut bacteria were deleted by broad-spectrum antibiotics in mice. IIR was induced by clamping superior mesenteric artery. Intestinal injury, permeability, epithelial proliferation, and proinflammatory activity of mesenteric lymph were investigated. Commensals deletion improved mice survival in the early phase, but failed to improve the overall survival at 96 h after IIR. Commensals deletion reduced proliferation of intestinal epithelial cells (IEC) and augmented proinflammatory activity of mesenteric lymph after IIR. Lipopolysaccharides (LPS) supplement promoted IEC proliferation and improved survival in mice with commensals deletion after IIR. LPS induced production of prostaglandin E2 (PGE2) in mucosa via toll-like receptor 4-NFκB-cyclooxygenase 2 pathway. PGE2 enhanced IEC proliferation in vivo, which was preceded by activation of Akt and extracellular signal-regulated kinase (ERK) 1/2. Blocking of EGFR, PI3K/Akt activity abolished LPS-induced IEC proliferation. Commensal bacteria are essential for epithelial restitution after IIR, which enhance IEC proliferation via induction of PGE2.     

The nitric oxide donor molsidomine prevents ischemia/reperfusion injury of the adult rat small intestine

It is suggested that gastrointestinal mucosal blood flow depends on a balanced release of vasoactive substances from the endothelium. The present study investigated the effects of molsidomine on the small intestine after ischemia-reperfusion (I/R) injury in four groups of 10 rats each composed: (1) SO, sham operation; (2) untreated I/R; (3) ML, I/R plus molsidomine pretreatment; (4) L-NAME, I/R plus N-omega-nitro-L-arginine methyl ester pretreatment. Intestinal ischemia for 45 min and reperfusion for 60 min were applied. Ileum specimens were obtained to determine the tissue level of malondialdehyde (MDA) and histologic changes. Mean MDA levels in the SO, untreated I/R, ML, and L-NAME groups were 95.60 +/- 2.59, 136.90 +/- 4.35, 121.10 +/- 3.38, and 137.40 +/- 4.42 nmol/g wet tissue, respectively. Although the MDA level in the ML group was higher than in the SO group ( P < 0.0001), it was significantly lower compared to the untreated I/R and L-NAME groups ( P < 0.0001, P < 0.0001). Mucosal injury scores (MIS) in groups 1-4 were 0.2 +/- 0.42, 3.9 +/- 0.73, 1.5 +/- 0.70, and 4.1 +/- 0.56, respectively. In group 3 the MIS was significantly lower than in groups 2 and 4 ( P < 0.0001, P < 0.0001). Molsidomine plays a role in attenuating reperfusion injury of the small intestine by depression of tissue MDA levels and MIS and regulates post-ischemic intestinal perfusion while restoring the intestinal microcirculatory blood flow and histologic injury.     

Serum cytosolic beta-glucosidase activity in a rat model of necrotizing enterocolitis

The diagnosis of necrotizing enterocolitis (NEC) is made from a combination of clinical and radiographic findings. There are no useful screening biochemical markers of intestinal injury. The serum concentration of cytosolic beta-glucosidase (CBG), an enzyme found primarily in enterocytes, is markedly elevated in animal models of ischemia and bowel obstruction. We hypothesized that in a rat model of NEC, serum CBG activity would significantly increase before microscopic evidence of severe intestinal injury. Cohorts of 2-wk-old Sprague-Dawley rats (n = 10/cohort) were anesthetized and underwent laparotomy with occlusion of the superior mesenteric artery (SMA). Platelet-activating factor (200 microg/animal) was injected in the proximal duodenum. Serum and intestinal samples were obtained at time 0 (control) and 30, 60, and 90 min of ischemia (I) and after 90 min of I followed by 60 min of reperfusion (I/R). Histopathologic injury was categorized as either no or minimal injury or mural necrosis by two masked investigators and CBG activity was measured by ELISA. Data were analyzed with Fisher's exact test and ANOVA. Only the I/R group had significantly greater mural necrosis compared with the control group (90% versus 0%, respectively, p < 0.001). In contrast, CBG activity was significantly elevated after only 90 min of I and after I/R (15.1 +/- 5.6 and 16.4 +/- 4.3 units/mL, respectively, p < 0.05). We conclude that serum CBG is elevated before transmural intestinal injury in this model and may have utility as an early marker of ischemia in patients at risk for NEC.     

丙酮酸在幼鼠肠缺血再灌注损伤中的作用

目的 观察丙酮酸对急性阻塞性肠缺血再灌注（Ｉ／Ｒ）的影响。方法 ５０只Ｗｉｓｔａｒ大鼠（幼龄４０只和成年１０只）分为５组：手术对照组,缺血组,再灌注组,丙酮酸组,成年动物再灌注组。在６０ｍｉｎ缺血和１２０ｍｉｎ再灌注后,进行生化和组织病理学检测。结果 缺血组血清谷丙转氨酶（ＡＬＴ）值和肠粘膜损害较手术对照组明显升高,超氧化物歧化酶（ＳＯＤ）活性无明显变化;     

Tracheal gas insufflation as a lung-protective strategy: physiologic, histologic, and biochemical markers.

OBJECTIVE: Conventional mechanical ventilation in acute lung failure potentiates lung injury, which can be assessed by physiologic, histologic, and biochemical markers. Thus, new ventilation strategies are directed at reducing lung injury. Tracheal gas insufflation has been shown to reduce endotracheal tube prosthetic deadspace and peak inspiratory pressure during conventional mechanical ventilation. Our objective was to use physiologic, histologic, and biochemical markers to test the hypothesis that tracheal gas insufflation in acute lung injury is lung protective. DESIGN: Animal experiment. SETTING: University setting. SUBJECTS: Juvenile rabbits (n = 12; 1.95 +/- 0.1 SE kg). INTERVENTIONS: Rabbits were anesthetized, instrumented, paralyzed, and ventilated with Fio(2) = 1.0. Lung injury was induced with repeated saline lavage (10 mL/kg per lavage until Pao(2) 相似文献   

Does sucralfate prevent apoptosis occurring in the ischemia/reperfusion-induced intestinal injury?

BACKGROUND/PURPOSE: We have shown in a previous study that sucralfate is beneficial in the prophylaxis and treatment of hypoxia/reoxygenation-induced intestinal injury. The aim of this study is to investigate whether sucralfate has any effect on the prevention of apoptosis in the ischemia/reperfusion (I/R)-induced intestinal injury. METHODS: Rats were randomized into three groups. Group 1 and 2 were subjected to I/R. Group 1 (treatment group) received sucralfate while group 2 (treatment control group) did not. Group 3 served as a normal control group (sham group). The terminal ileum was harvested for histopathologic investigation by light microscopy. The presence of apoptotic enterocytes (DNA fragmentation in cell nuclei) was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) reaction. RESULTS: In treatment control group, 3 of 7 rats had severe inflammation. None of the sucralfate-treated rats showed severe inflammation, 6 of them only showed mild inflammatory changes (p < 0.05). The apoptotic percentage was found to be 37.1 +/- 9.4 in the sucralfate-treated group (group 1), whereas it was 45.4 +/- 3.9 in the untreated group (group 2) (p < 0.05). The sham group had a completely normal intestinal architecture. CONCLUSIONS: The present study shows that 1) the experimental model of I/R-induced intestinal injury induces enterocyte apoptosis; 2) sucralfate decreases enterocyte apoptosis in the experimental model of I/R-induced intestinal injury which may play a key role in the pathophysiological events leading to failure of the intrinsic gut barrier defense mechanisms.     

雌激素对青春期雌性大鼠肠缺血再灌注损伤的保护作用

目的：探讨雌激素对肠缺血再灌注损伤的影响。方法：取雌性青春期大鼠，分为卵巢切除组（20只）、对照组（10只）、雌二醇组（10只），大剂量雌二醇组（20只）。观察肠缺血30min再灌注60min后肠粘膜损伤程度(Chiu氏评分法），测定血清雌二醇，NO2^－／NO3^-和丙二醛水平。结果：雌二醇组和大剂量雌二醇组的Chiu氏评分法和丙二醛低于卵巢切除组，而NO2^-／NO3^－高于卵巢切除组。雌二醇Chiu氏评分法呈负相关，与NO2^-／NO3^3－呈正相关，结论：雌激素对青春期雌性大鼠肠缺血再灌注损伤有一定的保护作用。     

肺表面活性物质治疗大鼠

目的 了解外源性肺表面活性物质（PS）对小肠缺血再灌注所致肺损伤的治疗效果。方法 正常雄性SD大鼠27只,腹腔麻醉后随机分为3组（n ＝9）,A组：钳夹肠系膜上动脉10s作为对照;B组：阻断动脉1h后,去除阻断,形成再灌注2h;C组：模型制作同B组。PC以100mg/kg气道滴入。所有动物再机械通气2h。监测动脉血气（PaO2)1肺顺应性（Cdyn）和气道阻力（R）和病理改变。结果 血气分析B组PaO2进行性降低（B组与A组比较,P＜0．05）,C组PS治疗后PaO2较为稳定,不表现为进行性下降,120min时较病变组差异有显著性意义（C组与组比较,P＜0．05）,肺功能表现为B组Cdyn降低、R升高,治疗后Cdyn稳定,120min时略有升高（C组与B组比较,P＜0．05）,病理观察：B组肺水肿、间质出血、炎性细胞浸润及部分肺不张,C组治疗后病变减轻。结论 外源性肺表面活性物质在这种模型的肺损伤治疗中可明显改善肺功能。     

Intestinal ischemia reperfusion injury and multisystem organ failure

Intestinal ischemia-reperfusion is a common pathway for many diseases in infants, children, and adults, and this may lead to multiple organ dysfunction syndrome and death. While several studies have investigated reperfusion injury in cardiac, cerebral, and hepatic disease, limited work has been published on intestinal ischemia-reperfusion and its multiorgan effects.The authors have developed models of intestinal ischemia-reperfusion in rats and have demonstrated that intestinal reperfusion causes liver energy failure at normothermia. This is followed by 100% mortality within 4 hours of reperfusion. Moderate hypothermia (32 degrees C to 33 degrees C) induced throughout ischemia and reperfusion prevents liver energy failure, intestinal damage, and neutrophil infiltration in the lungs. Moderate hypothermia in this model of intestinal ischemia and reperfusion prevents mortality. Further studies are needed to establish whether therapeutic hypothermia is a useful intervention in the treatment of infants and children with intestinal injuries caused by ischemia and reperfusion.     

Amelioration of ischemia-reperfusion injury in rat intestine by pentoxifylline-mediated inhibition of xanthine oxidase.

BACKGROUND: Intestinal ischemia-reperfusion (IR) injury results in cell destruction, which may be mediated by the generation of reactive oxygen species, potentially toxic metabolites of xanthine oxidase. Pentoxifylline (PTX) possesses a variety of biochemical and antioxidant properties that can improve capillary flow and tissue oxygenation. Because of these combined effects, it has been hypothesized that pentoxifylline would protect against intestinal IR. METHODS: Young adult rats were randomly assigned to one of four experimental groups: IR/Placebo (n = 12) in which superior and inferior mesenteric arteries were clamped for 45 minutes and then reopened; IR/PTX (n = 11) in which IR was induced as in the Placebo group, but with 25 mg/kg PTX at 0, 30, and 60 minutes; No IR/Placebo (n = 12); and No IR/PTX (n = 6) in which placebo and PTX were applied with no IR. Blood and intestinal samples were taken for serial thiobarbituric acid-reducing substances (TBARS; index of lipid peroxidation), for xanthine oxidase-xanthine dehydrogenase ratios, glutathione, myeloperoxidase, and histopathology. RESULTS: Animals in the IR/PTX group had lower TBARS and the least severe histopathologic injury. Xanthine oxidasexanthine dehydrogenase ratios were elevated only in IR/ Placebo (0.67+/-0.22 vs. 0.45+/-0.14 in IR/PTX; 0.42+/-0.22 in No IR/Placebo; and 0.40+/-0.11 in No IR/PTX; p = 0.0009). Reduced glutathione was diminished in IR/PTX animals (38.9 +/-1.35 vs. 46.1+/-7.0 in IR/Placebo; 41.1+/-2.5 in No IR/ Placebo; 43.6+/-1.0 in No IR/PTX; p = 0.048). No differences were recorded in myeloperoxidase levels among groups. CONCLUSIONS: Pentoxifylline ameliorates histopathologic signs of injury and decreases lipid peroxidation (TBARS). Normal xanthine oxidase-xanthine dehydrogenase ratios in the treated compared with IR-only animals imply that the protective effect of PTX is at least partially mediated through inhibition of xanthine oxidase.     

Effect of simvastatin on intestinal recovery following gut ischemia–reperfusion injury in a rat

Background

Pleiotropic (lipid lowering-independent) effects of statins are attributed to their antiinflammatory, antioxidant, and/or vascular actions. Extensive studies in various experimental models have established that pretreatment with simvastatin significantly protects heart and kidney injured by ischemia–reperfusion (IR). The purpose of the present study was to examine the effect of simvastatin on intestinal recovery and enterocyte turnover after intestinal IR injury in rats.

Methods

Male Sprague–Dawley rats were divided into three experimental groups: (1) sham rats underwent laparotomy, (2) IR-rats underwent occlusion of both superior mesenteric artery and portal vein for 30 min followed by 48 h of reperfusion, and (3) IR-SIM rats underwent IR and were treated with oral simvastatin (10 mg/kg) given by gavage immediately before and 24 h after operation. Intestinal structural changes, Park’s injury score, enterocyte proliferation and enterocyte apoptosis were determined 24 h following IR. A non-parametric Kruskal–Wallis ANOVA test was used for statistical analysis with P less than 0.05 considered statistically significant.

Results

Treatment with simvastatin resulted in a significant increase in bowel and mucosal weight in ileum, villus height and crypt depth in jejunum and ileum compared to IR animals. IR-SIM rats had also a significantly lower intestinal injury score as well as lower apoptotic index in jejunum and ileum compared to IR animals.

Conclusions

Treatment with simvastatin prevents gut mucosal damage and inhibits programmed cell death following intestinal IR in a rat.     

白藜芦醇对大鼠肠缺血再灌注损伤的保护作用

目的 探讨白藜芦醇(resveratro1,RES)对实验性大鼠肠缺血再灌注肠黏膜损伤的保护作用.方法 24只成年雄性SD大鼠随机分为假手术组(SO)、缺血再灌注损伤组(I/R)、RES治疗组.SO组仅分离肠系膜上动脉(SMA)根部而不夹闭.肠缺血再灌注损伤组(I/R)和RES治疗组均用无损伤血管夹夹闭SMA根部后分别立即经阴茎背静脉注射生理盐水、RES(20 mg/kg),45 min之后放松血管夹形成再灌注.各组大鼠均于制模后6 h采集标本.检测血清和回肠组织中的超氧化物歧化酶(SOD)和丙二醛(MDA)的含量,TUNEL法检测肠黏膜上皮细胞凋亡率,并观察肠黏膜病理变化.结果 小肠缺血再灌注后,血清及小肠组织中反映氧化损伤程度的MDA明显升高,SOD则明显减少,小肠黏膜上皮细胞凋亡,应用RES后能显著改善上述改变.结论 白藜芦醇对肠缺血再灌注损伤具有保护作用,其机制可能与通过抗氧化作用及抑制肠黏膜上皮细胞凋亡有关.

Abstract：

Objective To study the protective effects of resveratrol (RES) on intestinal ischemia-reperfusion injury in rats.Methods Twenty-four SD rats were randomly divided into the sham operation group,intestinal ischemia-reperfusion injury (I/R) group and resveratrol treated (RES) group.The intestinal ischemia injury was induced by superior mesenteric artery occlusion for 45 minutes,and then the blood supply to the intestine was restored to cause reperfusion injury.After 6 hours' reperfusion,the rats were sacrificed and intestine was collected.Of the RES group,the rats were subjected to I/R injury,and treated with 20 mg/kg resveratrol by intravenous injection immediately after the mesenteric artery was clamped.Superoxide Dismutase (SOD) and Malonaldehyde (MDA) levels in serum and intestine were measured.Apoptotic intestinal epithelial cells were detected by TUNEL methods.The histological injury of the intestine was also examined.Results Compared with the sham operated rats,MDA levels in the serum and intestine as well as the apoptotic epithelial cells were significantly increased in the rats subjected to I/R (MDA in serum and intestine 4.63±0.53 vs 1.32±0.40;8.60± 0.98 vs 4.13±0.86,P＜0.01;apoptotic index 66.63 ± 1.71 vs 46.72 ± 1.50,P＜0.01 ).However,the SOD levels in the serum and intestine were decreased (49.21±4.38 vs 86.65±6.14;351.03 ± 21.46 vs 468.93 ± 16.21,P＜0.01).In the rats subjected to I/R injury but received resveratrol treatment,the epithelial cells apoptosis and MDA levels in serum and intestine were decreased,and SOD levels in serum and intestine increased (P＜0.05).Conclusions Resveratrol protects intestine from ischemia-reperfusion injury in rats.     

Effect of taurine on intestinal recovery following intestinal ischemia-reperfusion injury in a rat

Purpose

Taurine (TAU) is a sulfur-containing amino acid that is involved in a diverse array of biological and physiological functions, including bile salt conjugation, osmoregulation, membrane stabilization, calcium modulation, anti-oxidation, and immunomodulation. Several studies have established that treatment with TAU significantly protects cerebral, cardiac and testicular injury from ischemia–reperfusion (IR). The purpose of the present study was to examine the effect of TAU on intestinal recovery and enterocyte turnover after intestinal IR injury in rats.

Methods

Male Sprague–Dawley rats were divided into four experimental groups: (1) Sham rats that underwent laparotomy, (2) Sham-TAU rats that underwent laparotomy and were treated with intraperitoneal (IP) TAU (250 mg/kg); (3) IR-rats that underwent occlusion of both superior mesenteric artery and portal vein for 30 min followed by 48 h of reperfusion, and (4) IR-TAU rats that underwent IR and were treated with IP TAU (250 mg/kg) immediately before abdominal closure. Intestinal structural changes, Park’s injury score, enterocyte proliferation and enterocyte apoptosis were determined 24 h following IR. The expression of Bax, Bcl-2, p-ERK and caspase-3 in the intestinal mucosa was determined using Western blot and immunohistochemistry.

Results

Treatment with TAU resulted in a significant decrease in Park’s injury score compared to IR animals. IR-TAU rats also demonstrated a significant increase in mucosal weight in jejunum and ileum, villus height in jejunum and ileum and crypt depth in ileum compared to IR animals. IR-TAU rats also experienced significantly lower apoptotic indices in jejunum and ileum which was accompanied by a higher Bcl-2/Bax ratio compared to IR animals.

Conclusions

Treatment with taurine prevents gut mucosal damage and inhibits intestinal epithelial cell apoptosis following intestinal IR in a rat.

     

Effects of antenatal steroids on ischemic brain injury in near-term ovine fetuses

BACKGROUND: Hypoxia/ischemia in utero can result in brain damage to the fetus and newborn. Antenatal steroids are a routine part of the management of women who develop premature labor. Pretreatment of young postnatal rats with dexamethasone before hypoxic/ischemic insults has been reported to attenuate brain injury. However, the effects of antenatal steroids on ischemic brain injury in fetuses have not been investigated. OBJECTIVE: We examined the effects of maternally administered antenatal corticosteroids on ischemic brain injury in near-term ovine fetuses. METHODS: Chronically instrumented fetuses at 122 days of gestation were studied 12 h after the last of four 4 mg dexamethasone, or placebo injections were given over 48 h to the ewes. Groups were dexamethasone/ischemic, placebo/ischemic and sham-treated control. Fetuses were exposed to 30 min of carotid occlusion (ischemia) or no occlusion (control) and 72 h of reperfusion. Whole brain coronal sections stained with Luxol fast blue-hematoxylin-eosin were scored for white matter and cerebral cortical lesions. Both areas received pathological scores of 0 to 5 reflecting the degree of injury (0=0%, 1=1-10%, 2=11-50%, 3=51-90%, 4=91-99% and 5=100%). Bilateral carotid blood flow also was measured before, during and after brain ischemia in the dexamethasone/ischemic and placebo/ischemic groups. RESULTS: White matter (WM) and cerebral cortical scores did not differ between the dexamethasone/ischemic and placebo/ischemic (WM: 3.0+/-1.9 and 2.9+/-1.7; cortex: 3.1+/-1.7 and 2.6+/-1.8, mean+/-S.D.) groups. White matter and cerebral cortical scores were higher in the dexamethasone/ischemic (WM: 3.0+/-1.9, P<0.02; cortex: 3.1+/-1.7, P<0.005) and placebo/ischemic (WM: 2.9+/-1.7, P<0.006; cortex: 2.6+/-1.8, P<0.007) than control (WM: 0.2+/-0.4; cortex: 0.2+/-0.4) group. Carotid blood flow was relatively higher (P<0.05) after 24, 48 and 72 h of reperfusion in the dexamethasone/ischemic than placebo/ischemic group. CONCLUSIONS: We conclude that maternal pretreatment with antenatal dexamethasone did not attenuate ischemic brain injury in the fetus, and that carotid blood flow was higher during reperfusion in fetuses of dexamethasone than placebo-treated ewes, most likely secondary to decreases in arterial oxygen tension.     

Pentoxifylline attenuates ischemia/reperfusion injury to the small intestine in the rat

There is a large body of evidence that neutrophils may play an important role in the mucosal injury that follows ischemia of the intestine. Pentoxifylline (PTF), a methylxanthine derivative, prevents leukocyte adherence to vascular endothelium and restores intestinal blood flow following hemorrhagic shock and sepsis. The purpose of this study was to evaluate the protective properties of PTF in an ischemia-reperfusion model of the intestine and whether its action is mediated through tissue neutrophils as assessed by myeloperoxidase (MPO) determination. Intestinal ischemia of either 1 or 2 h was induced in rats by clamping the superior mesenteric artery, followed by a 17-min reperfusion period. PTF (25 mg/kg) or saline solution was injected IP 10 min prior to ischemia. Multiple bowel samples were harvested at the end of the reperfusion period and evaluated for histology and tissue MPO. PTF significantly changed the resultant histologic damage to the intestinal mucosa exerted by prolonged ischemia of 1 and 2 h duration, although the beneficial effect of PTF in this animal model was independent of the number of tissue neutrophils as assessed by tissue MPO levels. Pretreatment with PTF can thus reduce the histologic damage caused by prolonged ischemia to the intestine.     

Effects of exogenous glucose on brain ischemia in ovine fetuses

We examined the effects of prolonged moderate hyperglycemia with and without an additional rapid glucose injection on ischemic brain injury in the fetus. Twenty-five ewes (117-124 d of gestation) were assigned to one of four groups: 1) glucose-infused fetuses exposed to 30 min of carotid artery occlusion followed by 48 h of reperfusion (I/R-Glu, n = 8); 2) glucose-infused plus rapid glucose injection given 100 min before 30 min of occlusion followed by 48 h of reperfusion (I/R-GluR, n = 4); 3) placebo-infused exposed to 30 min of occlusion and 48 h of reperfusion (I/R-PL, n = 8); and 4) glucose-infused sham occlusion and 48 h of sham reperfusion (control, n = 5). After baseline measurements, fetuses were infused with glucose (9-16 mg/kg/min) for 48 h before and after carotid occlusion or sham treatment. The I/R-PL group received 0.9% NaCl. Brain pathologic outcome was determined. Serial sections stained with Luxol fast blue-hematoxylin and eosin were scored for white matter, cerebral cortical, and hippocampal lesions. These areas received graded pathologic scores of 0 to 5, reflecting the amount of injury, where 0 = 0%, 1 = 1-25%, 2 = 26-50%, 3 = 51-75%, 4 = 76-95%, and 5 = 96-100% of the area damaged. Comparisons of the pathologic scores for cerebral cortex (CC), white matter (WM), and hippocampus (H) demonstrated that the I/R-GluR (CC: 4.56 +/- 0.11, WM: 4.50 +/- 0.11, H: 3.44 +/- 0.48, mean +/- SEM) had more (p < 0.05) damage than the I/R-Glu (CC: 2.46 +/- 0.47, WM: 1.97 +/- 0.37, H: 1.81 +/- 0.36) and control (CC: 1.12 +/- 0.13, WM: 0.82 +/- 0.34, H: 0.80 +/- 0.34) groups. The pathologic scores in the I/R-Glu were (p < 0.05) greater than the control, but not the I/R-PL (CC: 2.12 +/- 0.35, WM: 2.20 +/- 0.44, H: 1.59 +/- 0.41) group. We conclude that exposure to prolonged moderate hyperglycemia before ischemia and during reperfusion does not affect the extent of brain injury, but exposure to an additional acute increase in plasma glucose concentration before ischemia is extremely detrimental to the fetal brain.     

Resveratrol reduces ischemia reperfusion injury after experimental testicular torsion.

The aim of the study was to evaluate the effects of resveratrol on testicular ischemia reperfusion injury. Forty Wistar albino rats were divided into 4 groups. Torsions (ischemia) were created by rotating the right testis 720 degrees in a clockwise direction for 4 hours in all groups except the control group. In the torsion group after 4 hours' ischemia bilateral orchiectomy was performed. In the detorsion group, saline was injected by an intraperitoneal route, 30 min before detorsion (reperfusion). In the resveratrol group, 30 mg/kg resveratrol was injected by an intraperitoneal route, 30 min before detorsion. In the detorsion and resveratrol groups, the bilateral testes were removed after 20 hours of detorsion. In all groups, the tissue levels of malondialdehyde (MDA) and glutathione (GSH) and histological changes were determined. In rats treated with resveratrol, MDA levels (138 +/- 25 nmol/mg protein) were significantly decreased compared with torsion (426 +/- 178 nmol/mg protein) and detorsion (370 +/- 76 nmol/mg protein) groups (p < 0.05). GSH levels (6.54 +/- 0.8 micromol/g wet tissue) were significantly increased compared with torsion (4.61 +/- 0.4 micromol/g wet tissue) and detorsion groups (5.24 +/- 0.9 micromol/g wet tissue) (p < 0.05). The mean testicular tissue injury score in the resveratrol group was significantly lower than in torsion and detorsion groups (p < 0.05). The present study demonstrates that intraperitoneal administration of resveratrol in rats may protect testis against injury associated with reperfusion.     

Comparative analysis of adenosine triphosphate-magnesium chloride and allopurinol following small-bowel ischemia

The intestinal lesions caused by ischemia and reperfusion may lead to grave sequelae. To study the efficacy of adenosine triphosphate magnesium chloride (ATP-MgCl₂) and allopurinol (ALLO) in protecting the small bowel from ischemia, rabbits in two groups, 1 (n = 7) and 2 (n = 7), were pretreated with either 1 ml saline or ATP-MgCl₂ just prior to intestinal ischemia and reperfusion. Group 3 (n = 7) animals recieved enteral ALLO daily for 3 days before the experiment. Using Oldham and Thompson's grading system, histologic specimens were evaluated blindly for evidence of ischemic-reperfusion injury. The histologic injury scores in group 2 were significantly lower than those in groups 1 and 3 (P <0.05 and 0.02, respectively) after 2 h of ischemia. Following 30 min of reperfusion, histologic injury scores rose significantly in group 1 (P <0.05), decreased in group 2 (P <0.005), and showed no significant changes in group 3 (P >0.50). We conclude that: (1) pretreatment with ALLO can prevent reperfusion injury of the small intestine; and (2) ATP-MgCl₂ administration can reduce 2-h ischemic intestinal damage, reverse reperfusion-induced cellular injury, and improve the recovery of ischemic bowel during the reperfusion phase. Correspondence to: X.-p. Liao     

The effects of milrinone on hemodynamics in an experimental septic shock model.

OBJECTIVE: To investigate the specific hemodynamic effects of the phosphodiesterase inhibitor milrinone in a rabbit model of septic shock in the absence of any other treatment. DESIGN: A prospective, controlled, interventional study. Animal Model: Fourteen sedated New Zealand rabbits. SETTING: Research laboratory of a health sciences university. INTERVENTIONS: Rabbits were anesthetized and vascular catheters inserted in femoral artery and jugular vein. After a stabilization period and the recording of baseline measurements (H0), all animals received a 10-mL infusion of Pseudomonas aeruginosa. Two hours later (H2rabbits were randomly assigned to receive 5% dextrose (control group) or milrinone (milrinone group). MEASUREMENTS AND MAIN RESULTS: Mean arterial blood pressure (MAP) was monitored continuously, and a cardiac index (CI) was determined every 30 mins by a transpulmonary thermodilution technique using an integrated monitoring device (PICCO). No differences were detected between the two groups after stabilization (H0) or before the treatment (H2) for either CI (mL/min(-1)/kg(-1)) or MAP (mm Hg). CI decreased progressively in the control group during the following 4 hrs, but not in the treated group (at H6: 122 +/- 4 vs. 207 +/- 16 mL/min(-1)/kg(-1); p < .05). No drop of MAP occurred after milrinone infusion. A comparison of the treated and control group reveals that milrinone improved tissue perfusion as evidenced by measurements of central venous saturation (at H4: 0.59 +/- 0.05 vs. 0.71 +/- 0.03, p = .04), lactacidemia (at H6: 10.3 +/- 2.4 vs. 3.9 +/- 0.9 mmol/L, p = .03), creatinemia (at H6: 95 +/- 11 vs. 60 +/- 5 micromol/L, p = .02) and survival (at H6: 5 vs. 7, not significant). CONCLUSION: Milrinone improves cardiac output and tissue perfusion in a rabbit model involving severe septic shock.