Infiltration of Mast Cells in Rat Colon Is a Consequence of Ischemia/Reperfusion

Intestinal ischemia as well as mastocytosis occur in patients with inflammatory bowel disease and irritable bowel syndrome. Our aim was to clarify how ischemia with reperfusion (I/R) affects the structure, enteric neurons, and immune cells in the colon. Rats were subjected to colon ischemia for 1 h and reperfused for 1 day up to 20 weeks; sham-operated rats were used as controls. No structural remodeling of the intestinal segment was detected after I/R. The number and distribution of eosinophils were not affected by I/R. Local areas containing numerous mast cells were detected in the muscle layers, the serosa, and in and around the myenteric ganglia 4–20 weeks post ischemia. It was notable that myenteric ganglionic formations within mast-cell-rich areas virtually lacked neurons. Mast cells were rarely found in controls. In conclusion, I/R of the colon attracts mast cells, and death of myenteric neurons occurs in such locations.     

Activation of phosphorylating-p38 mitogen-activated protein kinase and its relationship with localization of intestinal stem cells in rats after ischemia-reperfusion injury

AIM: To investigate the expression of phosphorylating p38 mitogen-activated protein kinase (MAPK) in rat small intestine after ischemia-reperfusion (I/R) insult and its relationship with the localization of intestinal stem cells. METHODS: Forty-eight Wistar rats were divided randomly into three groups, namely intestinal ischemia-reperfusion group (R), intestinal ischemia group (I) and sham-operated control group (C). In group I, the animals were killed 45 minutes after superior mesenteric artery (SMA) occlusion, while in group R the rats sustained SMA occlusion for 45 minutes and reperfusion for 2, 6, 12 or 24 hours respectively. In sham-operated control group, SMA was separated, but without occlusion. The activity of plasma diamine oxidase (DAO) was determined. Intestinal tissue samples were also taken for histological analysis and immunohistochemical analysis of MAPK p38 detection and intestinal stem cell localization. RESULTS: The changes in histological structure and plasma DAO levels indicated that the intestinal barrier was damaged after intestinal I/R injury. In group C and I, each crypt contained 5-6 p38 MAPK positive cells, which were mainly located in the lower region of the crypts. This was consistent with the distribution of intestinal stem cells. The presence of positive cells in crypts increased with the time of reperfusion and reached its peak at 12 hours after reperfusion (35.6 %). CONCLUSION: After intestinal I/R injury, the expression of phosphorylating-p38 MAPK in small intestine increased with the duration of reperfusion, and its distribution coincided with that of intestinal stem cells and their daughter cells, indicating that phosphorylating-p38 might be a possible marker of intestinal stem cells.     

Effects of Ischemia and Reperfusion on Subpopulations of Rat Enteric Neurons Expressing the P2X7 Receptor

Background

Intestinal ischemia followed by reperfusion (I/R) may occur following intestinal obstruction. In rats, I/R in the small intestine leads to structural changes accompanied by neuronal death.

Aim

To analyze the impact of I/R injury on different neuronal populations in the myenteric plexus of rat ileum.

Methods

The ileal artery was occluded for 35 min and animals were euthanized 6, 24, and 72 h, and 1 week later. Immunohistochemistry was performed with antibodies against the P2X7 receptor as well as nitric oxide synthase (NOS), calbindin, calretinin, choline acetyltransferase (ChAT), or the pan-neuronal marker anti-HuC/D.

Results

Double immunolabeling demonstrated that 100 % of NOS-, calbindin-, calretinin-, and ChAT-immunoreactive neurons in all groups expressed the P2X7 receptor. Following I/R, neuronal density decreased by 22.6 % in P2X7 receptor-immunoreactive neurons, and decreased by 46.7, 38, 39.8, 21.7, and 20 % in NOS-, calbindin-, calretinin-, ChAT-, and HuC/D-immunoreactive neurons, respectively, at 6, 24, and 72 h and 1 week following injury compared to the control and sham groups. We also observed a 14 % increase in the neuronal cell body profile area of the NOS-immunoreactive neurons at 6 and 24 h post-I/R and a 14 % increase in ChAT-immunoreactive neurons at 1 week following I/R. However, the average size of the calretinin-immunoreactive neurons was reduced by 12 % at 6 h post-I/R and increased by 8 % at 24 h post-I/R.

Conclusions

This work demonstrates that I/R is associated with a significant loss of different subpopulations of neurons in the myenteric plexus accompanied by morphological changes, all of which may underlie conditions related to intestinal motility disorder.     

Acid fibroblast growth factor reduces rat intestinal mucosal damage caused by ischemia-reperfusion insult

AIM: To detect the effects of acid fibroblast growth factor (aFGF) on apoptosis and proliferation of intestinal epithelial cells in differentiation or proliferation status to explore the protective mechanisms of aFGF. METHODS: Wistar rats were randomly divided into sham-operated control group (C, n= 6), intestinal ischemia group (I,n = 6), aFGF treatment group (A, n= 48) and intestinal ischemia-reperfusion group (R,n= 48). Apoptosis of intestinal mucosal cells was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) technique. Proliferating cell nuclear antigen (PCNA) protein expression and distribution were detected with immunohistochemical method. Plasma levels of D-lactate were determined with modified Brandts method. RESULTS: In A group, administration of exogenous aFGF could improve intestinal histological structure and decrease plasma D-lactate levels at 2-12 h after the reperfusion compared with R group. The apoptotic rates and PCNA protein expressions were not increased until 2 h after reperfusion and were maximal at 12 h. After reperfusion for 2-12 h, the apoptotic rates were gradually augmented along the length of jejunal crypt-villus units. Administration of aFGF could significantly reduce the apoptotic response at 2-12 h after reperfusion (P<0.05). Apoptosis rates in villus and crypt epithelial cells in A group at 12 h after reperfusion were (62.5±5.5)% and (73.2±18.6)% of those in R group, respectively. Treatment of aFGF could apparently induce protein expression of PCNA in intestinal mucosal cells of A group compared with R group during 2-12 h after reperfusion (P<0.05). There were approximately 1.3- and 1.5-times increments of PCNA expression levels in villus and crypt cells in A group at 12 h after reperfusion compared with R group, respectively. CONCLUSION: Intestinal I/R insult could lead to histological structure change and apoptotic rate increment. The protective effects of aFGF against ischemia/reperfusion in rat intestinal mucosa might be partially due to its ability to inhibit ischemia/reperfusion-induced apoptosis and to promote cell proliferation of crypt cells and villus epithelial cells.     

Oligoneuronal Hypoganglionosis in Patients with Idiopathic Slow-Transit Constipation

PURPOSE: Several alterations of the enteric nervous system have been described as an underlying neuropathologic correlate in patients with idiopathic slow-transit constipation. To obtain comprehensive data on the structural components of the intramural nerve plexus, the colonic enteric nervous system was investigated in patients with slow-transit constipation and compared with controls by means of a quantitative morphometric analysis. METHODS: Resected specimens were obtained from ten patients with slow-transit constipation and ten controls (nonobstructive neoplasias) and processed for immunohistochemistry with the neuronal marker Protein Gene Product 9.5. The morphometric analysis was performed separately for the myenteric plexus and submucous plexus compartments and included the quantification of ganglia, neurons, glial cells, and nerve fibers. RESULTS: In patients with slow-transit constipation, the total ganglionic area and neuronal number per intestinal length as well as the mean neuron count per ganglion were significantly decreased within the myenteric plexus and external submucous plexus. The ratio of glial cells to neurons was significantly increased in myenteric ganglia but not in submucous ganglia. On statistical analysis, the histopathologic criteria (submucous giant ganglia and hypertrophic nerve fibers) of intestinal neuronal dysplasia previously described in patients with slow-transit constipation were not completely fulfilled. CONCLUSION: The colonic motor dysfunction in slow-transit constipation is associated with quantitative alterations of the enteric nervous system. The underlying defect is characterized morphologically by oligoneuronal hypoganglionosis. Because the neuropathologic alterations primarily affect the myenteric plexus and external submucous plexus, superficial submucous biopsies are not suitable to detect these innervational disorders.     

Rapid mitogen－activated protein kinase by basic fibroblast growth factor in rat intestine after ischemia／reperfusion injury

AIM: Previous studies showed that exogenous basic fibroblast growth factor (bFGF or FGF-2) could improve physiological dysfunction after intestinal ischemia/ reperfusion (I/R) injury. However, the mechanisms of this protective effect of bFGF are still unclear. The present study was to detect the effect of bFGF on the activities of mitogen-activated protein kinase (MAPK) signaling pathway in rat intestine after I/R injury, and to investigate the protective mechanisms of bFGF on intestinal ischemia injury. METHODS: Rat intestinal I/R injury was produced by clamping the superior mesenteric artery (SMA) for 45 minutes and followed by reperfusion for 48 hours. Seventy-eight Wistar rats were used and divided randomly into sham-operated group (A), normal saline control group (B), bFGF antibody pre-treated group (C), and bFGF treated group (D). In group A, SMA was separated without occlusion. In groups B, C and D, SMA was separated and occluded for 45 minutes, then, released for reperfusion for 48 hours. After the animals were sacrificed, blood and tissue samples were taken from the intestine 45 minutes after ischemia in group A and 2, 6, 24, and 48 hours after reperfusion in the other groups. Phosphorylated forms of p42/p44 MAPK, p38 MAPK and stress activated protein kinase/C-Jun N-terminal kinase (SAPK/JNK) were measured by immunohistochemistry. Plasma levels of D-lactate were examined and histological changes were observed under the light microscope. RESULTS: Intestinal I/R injury induced the expression of p42/p44 MAPK, p38 MAPK, and SAPK/JNK pathways and exogenous bFGF stimulated the early activation of p42/p44 MAPK and p38 MAPK pathways. The expression of phosphorylated forms of p42/p44 MAPK was primarily localized in the nuclei of crypt cells and in the cytoplasm and nuclei of villus cells. The positive expression of p38 MAPK was localized mainly in the nuclei of crypt cells, very few in villus cells. The activities of p42/p44 MAPK and p38 MAPK peaked 6 hours after reperfusion in groups B and C, while SAPK/JNK peaked 24 hours after reperfusion. The activities of p42/p44 MAPK and p38 MAPK peaked 2 hours after reperfusion in group D and those of SAPK/JNK were not changed in group B. D-lactate levels and HE staining showed that the intestinal barrier was damaged severely 6 hours after reperfusion; however, histological structures were much improved 48 hours after reperfusion in group D than in the other groups. CONCLUSION: The results indicate that intestinal I/R injury stimulates the activities of MAPK pathways, and that p42/p44 MAPK and p38MAPK activities are necessary for the protective effect of exogenous bFGF on intestinal I/R injury. The protective effect of bFGF on intestinal dysfunction may be mediated by the early activation of p42/p44 MAPK and p38 MAPK signaling pathways.     

Rapid mitogen-activated protein kinase by basic fibroblast growth factor in rat intestin after ischemia/reperfusion injury

AIM: Previous studies showed that exogenous basic fibroblast growth factor (bFGF or FGF-2) could improve physiological dysfunction after intestinal ischemia/reperfusion (I/R) injury. However, the mechanisms of this protective effect of bFGF are still unclear. The present study was to detect the effect of bFGF on the activities of mitogen-activated protein kinase (MlAPK) signaling pathway in rat intestine after I/R injury, and to investigate the protective mechanisms of bFGF on intestinal ischemia injury. METttODS: Rat intestinal I/R injury was produced by clamping the superior mesenteric artery (SMA) for 45minutes and followed by repeffusion for 48 hours. Seventyeight Wistar rats were used and divided randomly into sham-operated group (A), normal saline control group (B),bFGF antibody pre-treated group (C), and bFGF treated group (D). Tn group A, SMA was separated without occlusion. In groups B, C and D, SMA was separated and occluded for 45 minutes, then, released for reperfusion for 48 hours. After the animals were sacrificed, blood and tissue samples were taken from the intestine 45 minutes after ischemia in group A and 2, 6, 24, and 48 hours after reperfusion in the other groups. Phosphorylated forms of p42/p44 MAPK, p38 MAPK and stress activated protein kinase/C-Jun N-terminal kinase (SAPK/JNK) were measured by immunohistochemistry. Plasma levels of D-lactate were examined and histological changes were observed under the light microscope. RESULTS: Intestinal I/R injury induced the expression of p42/p44 MAPK, p38 MAPK, and SAPK/JNK pathways and exogenous bFGF stimulated the early activation of p42/p44 MAPK and p38 MlAPK pathways. The expression of phosphorylated forms of p42/p44 MAPK was primarily localized in the nuclei of crypt cells and in the cytoplasm and nuclei of villus cells. The positive expression of p38MAPK was localized mainly in the nuclei of crypt cells, very few in villus cells. The activities of p42/p44 MAPK and p38MAPK peaked 6 hours after reperfusion in groups B and C,while SAPK/JNK peaked 24 hours after reperfusion. The activities of p42/p44 MAPK and p38 MAPK peaked 2 hours after reperfusion in group D and those of SAPK/JNK were not changed in group B. D-lactate levels and HE staining showed that the intestinal barrier was damaged severely 6hours after reperfusion; however, histological structures were much improved 48 hours after reperfusion in group D than in the other groups. CONCLUSION: The results indicate that intestinal I/R injury stimulates the activities of MAPK pathways, and that p42/p44 MAPK and p38MAPK activities are necessary for the protective effect of exogenous bFGF on intestinal I/R injury.The protective effect of bFGF on intestinal dysfunction may be mediated by the early activation of p42/p44 MAPK and p38 MAPK signaling pathways.     

老龄大鼠脑缺血再灌注损伤与明胶酶系基因表达的关系

目的研究老龄大鼠脑缺血再灌注不同时期微血管基底膜损伤与明胶酶系基因表达的关系。方法制备SD雄性大鼠局灶性脑缺血再灌注模型,将56只青年大鼠分为青年假手术组、青年模型组,56只老龄大鼠分为老龄假手术组、老龄模型组,其中青年与老龄模型组又分缺血3h和再灌注6、12、24h,3、6天时间点。观察脑微血管结构基底膜病理形态变化和明胶酶系的基因表达变化。结果老龄假手术组大鼠脑皮质微血管结构基本正常,老龄模型组与同时间点青年模型组比较病理损伤较重。随再灌注时间的延长,基质金属蛋白酶-2(MMP-2)mRNA表达递增,基质金属蛋白酶-9(MMP-9)mRNA和金属蛋白酶组织抑制-1(TIMP-1)mRNA表达呈先增强后降低趋势。与青年模型组相同时间点比较,老龄模型组MMP-2、MMP-9mRNA表达水平增强;TIMP-1mRNA仅在再灌注24h表达水平降低,差异均有显著性。结论随着增龄,大鼠脑微血管基底膜损伤改变与MMPmRNA、TIMPmRNA的变化有关。老龄大鼠较青年大鼠病理损伤严重。     

Melatonin reduces torsion-detorsion injury in rat ovary: biochemical and histopathologic evaluation

This experimental study was designed to determine the effects of melatonin on the levels of malondialdehyde (MDA), reduced glutathione (GSH), xanthine oxidase (XO) after adnexial torsion/detorsion (ischemia/reperfusion, I/R) of the ovaries of in rats. Forty adult albino rats were divided into five groups: sham operation, torsion, I/R plus saline, I/R plus melatonin and torsion plus melatonin. Rats in the sham-operated group underwent a surgical procedure similar to the other groups but the adnexa was not occluded. Rats in the torsion group were killed after adnexal torsion for 3 hr. Melatonin and saline were injected intraperitoneally (10 mg/kg) 30 min before detorsion to the I/R plus melatonin group and I/R plus saline group respectively. After 3 hr of ovarian detorsion, the rats were killed and ovaries were removed. Melatonin was injected intraperitoneally (10 mg/kg) 30 min before torsion to the torsion plus melatonin group. After 3 hr of ovarian torsion, the rats were killed and ovaries were harvested. The tissue levels of MDA, GSH and XO were measured. MDA and XO levels in the I/R plus saline group increased significantly when compared with torsion and sham-operated groups (P < 0.001). MDA and XO levels in the I/R plus melatonin group were lower than I/R plus saline and differences between the two groups were statistically significant (P < 0.001). GSH levels in the I/R plus saline group decreased significantly when compared with ischemia and sham-operated groups (P < 0.001). GSH levels in the I/R plus melatonin treated rats were significantly higher than I/R plus saline and ischemia groups (P < 0.001). The tissue levels of XO, MDA and GSH were similar between ischemia and ischemia plus melatonin groups. Morphologically, polymorphonuclear neutrophil infiltration and vascular dilatation were obvious in the I/R-damaged ovaries, and the changes also partially reversed by melatonin. This study demonstrates that melatonin protects the ovaries against oxidative damage associated with reperfusion following an ischemic insult.     

Role of complement activation and mast cell degranulation in the pathogenesis of rapid intestinal ischemia/reperfusion injury in rats

The aim of this study is to define the putative role of complement activation and mucosal mast cell (MMC) degranulation in the pathogenesis of rapid ischemia-reperfusion (I/R) injury. We prepared complement activity-depleted rats by the administration of the anti-complementary agent K-76COONa. To assess the role of MMC degranulation, we used the MMC stabilizer MAR-99 and genetically mast cell-deficient Ws/Ws rats. Autoperfused segments of the jejunum were exposed to 60 min of ischemia, followed by 60 min reperfusion. The epithelial permeability was assessed by (51)Cr-EDTA clearance rate, and the number of MMC was immunohistochemically assessed. I/R treatment induced a marked increase in mucosal permeability and MMC degranulation. The treatment with K-76COONa and MAR-99 significantly attenuated these changes. Furthermore, in Ws/Ws rats the increase in mucosal permeability and MMC degranulation was significantly attenuated. These findings indicate the role of complement activation and MMC activation in the pathogenesis of rapid intestinal I/R injury. A regulation of the complement activation and MMC degranulation may be one of the clinical strategies for prevention of I/R-induced mucosal injury.     

Endogenous erythropoietin system in non-hematopoietic lineage cells plays a protective role in myocardial ischemia/reperfusion

OBJECTIVE: Recent studies suggested that erythropoietin (Epo) receptors (EpoR) are expressed not only in the hematopoietic lineage cells but also in the heart and that the administration of recombinant human Epo elicits protective effects in myocardial ischemia and reperfusion (I/R). We tested our hypothesis that endogenous Epo signals mediated by EpoR expressed in the non-hematopoietic lineage cells play a protective role against myocardial I/R injury. METHODS: Transgene-rescued EpoR null mutant mice (RES), which express EpoR exclusively in the hematopoietic lineage cells, were subjected to 30 min left coronary artery occlusion followed by reperfusion. RESULTS: Hematocrit, heart rate, blood pressure, heart weight, and echocardiographic parameters were comparable between wild-type mice (WT) and RES under the baseline condition. After 24 h of reperfusion, the infarct size in RES with I/R (RES/MI) was larger than that in WT/MI. Caspase-3 activity and number of TUNEL-positive cardiomyocytes in the ischemic area were increased in RES/MI compared with WT/MI. The extents of p38 and JNK phosphorylations in the ischemic area were significantly increased in WT/MI, but not in RES/MI as compared with corresponding sham-operated mice. Plasma Epo concentration in RES/MI did not differ from that in sham-operated RES, while that in WT/MI was peaked at 24 h post I/R. Additionally, left ventricular (LV) end-diastolic diameter was increased and LV fractional shortening tended to be reduced in the RES/MI compared with WT/MI at 21 days after I/R. CONCLUSIONS: These results suggest that the endogenous Epo-EpoR system in the non-hematopoietic lineage cells plays an important protective role against myocardial I/R injury.     

Inhibition of p38 mitogen-activated protein kinase may decrease intestinal epithelial cell apoptosis and improve intestinal epithelial barrier function after ischemia- reperfusion injury

AIM: To investigate the role of p38 mitogen-activated protein kinase in rat small intestine after ischemia-reperfusion (I/R) insult and the relationship between activation of p38 MAPK and apoptotic cell death of intestine. METHODS: Ninety Wistar rats were divided randomly into three groups, namely sham-operated group (C), I/R vehicle group (R) and SB203580 pre-treated group (S). In groups R and S, the superior mesenteric artery (SMA) was separated and occluded for 45 min, then released for reperfusion for 0.25, 0.5, 1, 2, 6, 12 and 24 h. In group C, SMA was separated without occlusion. Plasma D-lactate levels were examined and histological changes were observed under a light microscope. The activity of p38 MAPK was determined by Western immunoblotting and apoptotic cells were detected by the terminal deoxynucleotidyl transferase (TdT)-mediated dUDP-biotin nick end labeling (TUNEL). RESULTS: Intestinal ischemia followed by reperfusion activated p38 MAPK, and the maximal level of activation (7.3-fold vs sham-operated group) was reached 30 min after I/R. Treatment with SB 203580, a p38 MAPK inhibitor, reduced intestinal apoptosis (26.72±3.39% vs62.50±3.08% in I/R vehicle, P<0.01) and decreased plasma D-lactate level (0.78±0.15 mmol/L in I/R vehicle vs0.42±0.17 mmol/L in SB-treated group) and improved post-ischemic intestinal histological damage. CONCLUSION: p38 MAPK plays a crucial role in the signal transduction pathway mediating post-ischemic intestinal apoptosis, and inhibition of p38 MAPK may attenuate ischemia-reperfusion injury.     

Modulation of liver oxidant-antioxidant system by ischemic preconditioning during ischemia／reperfusion injury in rats

AIM: To investigate effects of ischemic pre-conditioning on the liver endogenous oxidant-antioxidant system during ischemia/reperfusion injury. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into sham-operated (Sham), ischemia/ reperfusion (I/R), ischemic pre-conditioning plus ischemia/ reperfusion (IPC) groups. Serum ALT, AST and hyaluronic acid levels were assayed and pathologic alterations observed. Liver malondialdehyde (MDA) contents, endogenous antioxidant enzymes, superoxidase dismutase (SOD), catalase (CAT), gultathionine peroxidase (GSH-Px) activities, neutrophils accumulation marker, myeloperoxidase (MPO) activities were measured respectively. RESULTS: Compared with I/R group, sinusoidal endothelial cells as well as hepatocytes damages, as assessed biochemically and histochemically, were improved significantly in IPC group; neutrophils infiltration was also markedly reduced. In IPC group, liver peroxidation, as measured by MDA contents, was significantly decreased when compared with I/R group; endogenous antioxidant enzymes, SOD, CAT and GSH-Px activities were markedly higher than that in I/R group. CONCLUSION: Ischemic pre-conditioning exerts protective effects on both hepatic sinusoidal endothelial cells and hepatocytes during liver I/R injury. Its mechanisms may involve dimunition of neutrophils infiltration and modulation of the imbalance of endogenous oxidant-antioxidant system in the organism.     

Ketamine and the Myenteric Plexus in Intestinal Ischemia/Reperfusion Injury

Background and Aims  

Intestinal ischemia/reperfusion (I/R) is a common clinical entity with severe consequences. We studied the effects of ketamine and the participation of the myenteric plexus in I/R injury.     

Differential changes in intrinsic innervation and interstitial cells of Cajal in small bowel atresia in newborns

AIM: To investigate morphological changes of the enteric nervous system (ENS) and the interstitial cells of Cajal (ICCs) in small bowel atresia.METHODS: Resected small bowel specimens from affected patients (n = 7) were divided into three parts (proximal, atretic, distal). Standard histology and enzyme immunohistochemistry anti-S100, anti-protein gene product (PGP) 9.5, anti-neurofilament (NF), antic-kit-receptor (CD117) was carried out on conventional paraffin sections of the proximal and distal part. RESULTS: The neuronal and glial markers (PGP 9.5, NF, S-100) were expressed in hypertrophied ganglia and nerve fibres within the myenteric and submucosal plexuses. Furthermore, the submucous plexus contained typical giant ganglia. The innervation pattern of the proximal bowel resembled intestinal neuronal dysplasia. The density of myenteric ICCs was clearly reduced in the proximal bowel, whereas a moderate number of muscular ICCs were found. The anti-CD117 immunore- action revealed additional numerous mast cells. The distal bowel demonstrated normal morphology and density of the ENS, the ICCs and the mast cells.CONCLUSION: The proximal and distal bowel in small bowel atresia revealed clear changes in morphology and density of the ENS and ICCs.     

Rat Small Intestinal Goblet Cell Kinetics in the Process of Restitution of Surface Epithelium Subjected to Ischemia–Reperfusion Injury

Repair of superficial damage to gastrointestinal mucosa occurs by a process called restitution. Goblet cells reside throughout the length of the intestine and are responsible for the production of mucus. However, a kinetic analysis of goblet cell dynamics of small intestine in restitution has hitherto not been reported. The aim of the present study was to investigate the role of goblet cells in the process of restitution of rat small intestine subjected to ischemia and ischemia–reperfusion injury, and therefore intestinal epithelium from rats subjected to both ischemia and ischemia–reperfusion was studied. Detachment of enterocytes was observed after 5-min of reperfusion. After 20–30 minutes of reperfusion, the denuded villous tips were covered with goblet cells. Within 75 min of reperfusion the epithelium restitution was complete. On the other hand, restitution was not observed in ischemia group. These data suggest that goblet cells may play an important role in restitution after ischemia–reperfusion injury.     

氨氯地平对钙调磷酸酶在心肌细胞凋亡中的作用

目的研究缺血再灌注(I/R)时氨氯地平对心肌细胞凋亡的影响及钙调磷酸酶的变化。方法结扎Wistar大鼠左冠状动脉前降支,缺血30 min复灌3 h,建立大鼠在体I/R动物模型。18只大鼠按是否给予氨氯地平干预分为3组(每组6只):假手术组、I/R组、I/R+氨氯地平组(术前7 d连续灌胃给氨氯地平10mg.kg-1.d-1)。用流式细胞术检测细胞凋亡率,RT-PCR法检测CaNmRNA表达。结果I/R组CaNmRNA的表达水平高于假手术组,同时心肌细胞凋亡率明显增加;氨氯地平组心肌细胞CaNmRNA的表达水平比I/R组明显下降(0.73±0.02vs.0.91±0.02,P<0.05),心肌细胞凋亡率也明显降低(6.33±0.77vs.17.30±1.01,P<0.05)。结论钙调磷酸酶有促进心肌细胞凋亡的作用。氨氯地平可能通过增加细胞膜及肌浆网上钙泵的表达有效减轻心肌细胞内的钙超载,降低CaN的活性抑制心肌细胞凋亡,对I/R心肌细胞具有保护作用。     

硫化氢对大鼠肠缺血再灌注后回肠收缩活性的保护作用

背景：肠缺血再灌注（I/R）在临床中较为常见,并可引起严重的并发症,目前仍缺乏有效的治疗药物。目的：研究硫化氢（H2S）对大鼠肠I/R后离体回肠收缩活性的影响及其机制。方法：24只Sprague-Dawley大鼠随机分为正常组、假手术组、I/R组（I1 h/R4 h）、H2S组（再灌注前20 min腹腔内注射硫氢化钠10μmol/kg）。记录离体回肠自发收缩频率和曲线下面积（AUC）,观察离体回肠对KCl（30 mmol/L）、乙酰胆碱（Ach）（10-5mol/L）、电场刺激（EFS）（30 V,10 Hz,1.00 ms,10 s）的反应。以免疫荧光染色检测肠肌间神经丛中Hu、胆碱乙酰转移酶（ChAT）阳性神经元表达。结果：与假手术组相比,I/R组和H2S组大鼠离体回肠自发收缩频率、对KCl和Ach的反应无明显改变。I/R组自发收缩AUC和对EFS的反应明显下降（P〈0.05）,Hu、ChAT阳性神经元表达均明显降低（P〈0.05）;给予H2S干预后,上述指标均明显升高（P〈0.05）。结论：H2S对大鼠肠I/R后回肠收缩活性可产生保护作用,其机制可能是减轻了肠神经元尤其是兴奋性神经元的损伤。     

Ketotifen abrogates local and systemic consequences of rat intestinal ischemia-reperfusion injury

BACKGROUND: Mast cell-derived vasoactive and pro-inflammatory mediators, particularly histamine, might contribute to local tissue damage and multiorgan dysfunction induced by intestinal ischemia/reperfusion (I/R). The purpose of the present study was to evaluate the effects of the mast cell stabilizer, ketotifen, on leukocyte adhesion within, and tissue leakage from the mucosal villous microcirculation after intestinal I/R. METHODS: Superior mesenteric arteries of untreated and ketotifen-pretreated (1 mg/kg orally twice daily for 3 days, and 90 min prior to ischemia) Piebald-Viral-Glaxo (PVG) rats were clamped for 30 min (n = 12 per group; sham operated controls n = 12). Mucosal surfaces of exteriorized ileal segments were visualized, and leukocyte adherence in, and macromolecular leakage (MML) from individual villi were followed for 2 h after clamp removal using in vivo microscopy. Blood pressure and heart rate were monitored, and lung tissue damage was assessed by histology. RESULTS: Ten untreated animals subjected to intestinal I/R failed to survive the reperfusion period, leukocyte adhesion (P < 0.001) and MML (P < 0.001) were increased at all time-points and blood flow stasis eventually ensued. In contrast, all ketotifen-pretreated I/R animals survived the duration of the study. Ketotifen abrogated I/R-induced leukocyte adherence within the villus mucosal capillaries and supplying arterioles and largely prevented pulmonary injury, yet surprisingly had no effect on intestinal vascular leakage. CONCLUSIONS: This is the first study to demonstrate that ketotifen is a powerful inhibitor of I/R-induced leukocyte adhesion and can prevent localized and reduce remote organ damage after intestinal I/R injury. However, its effects are manifested in the absence of any influence on intestinal I/R-induced vascular leakage.