Objective:To observe the effects of ischemic postconditioning (I-postC)on the lung injury after limb ischemia reperfusion (LIR)in the rats,and to investigate the protective effect and the possible mechanisms. Methods:24 Wistar rats were randomly divided into control group, ischemia-reperfusion group (IR group)and I-postC group (n=8 ). Referring to routine method in our department, the model rats which underwent 4 h ischemia and 4 h reperfusion of hind limbs were made.In control group,the rubber band around the limb was loose and the blood flow was not blocked. In I-postC group, before reperfusion, ischemia 5 min and reperfusion 5 min were performed in the rats,repeated for 3 times and then perfusion 4 h was taken,The blood and lung tissue from every rat were taken accurately. The percentages of CD1 8 positive cells in peripheral blood,the levels of soluble intercellular adhesion molecule-1 (sICAM-1)and P-selectin in plasma,the myeloperoxidase (MPO)activities in lung tissue,the levels of intercellular adhesion molecule-1 (ICAM-1)and P-selectin in lung tissue of the rats in various groups were detected. The partial pressure of oxygen (PaO2 ) and partial pressure of carbon dioxide (PaCO2 )were measured.The morphological changes of lung tissue under light and electron microscopes were observed.Results:Compared with control group,the percentage of CD18 positive cells and the levels of sICAM-1 and P-selectin of the rats in IR groups were increased (P<0.01);PaO2 and PaCO2 were decreased significantly;the MPO activity in lung tissue was also significantly increased (P<0.01).The HE staining results showed lung interstitial vascular dilation, congestion, PMN infiltration, the increased gap blood vessel, alveolar septal thickening,alveolar exudation, bronchial epithelial cell shedding and necrosis of the rats in IR group. Compared with IR group,the values of biochemical indicators mentioned above were decreased obviously (P<0.01);PaO2 and PaCO2 were increased significantly (P<0.01);the activities of inflammatory factors in plasma and lung tissue were decreased (P < 0.01 ); the pathological changes of lung damage were improved significantly. Conclusion:I-postC can reduce the lung injury after LIR in the rats,and the mechanism may be related to inhibiting the inflammatory reaction.

Objective To observe the effects of ischemic postconditioning (I-postC) on lung injury after limb ischemia reperfusion (LIR) in rats, and to investigate the protective effect and the mechanisms. Methods Twenty-four Wistar rats were divided into three groups:control group (group Control), ischemia-reperfusion group (group IR) and ischemic postcondi?tioning group (group I-postC). Referring to routine method in our department, the model rats underwent 4-hour ischemia and 4-hour reperfusion of hind limbs were made. In group Control, the rubber band around the limb was loose,which did not block the blood flow. Rats in group I-postC were given repeated 3 times of 5 min ischemia-5 min reperfusion, and then did perfusion 4 h before reperfusion. The blood and lung samples were collected for detecting arterial gas of partial pressure of oxygen [p(O2)] and partial pressure of carbon dioxide [p(CO2)]. The plasma and lung tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD) and xanthine oxidase (XOD) were detected. The morphological changes of lung tissue were ob?served under light microscope and electron microscope. Results It was found that after suffering from ischemia-reperfu?sion, levels of p(O2) and p(CO2) decreased significantly. The activity of SOD in plasma and lung tissues decreased, but XOD and MDA increased significantly (P<0.05). With microscope, lung interstitial vascular dilation, infiltration of neutrophils, the width of the alveolar space, alveolar septal thickening and alveolar exudate were found. Compared with IR group, it was found that p(O2) and p(CO2) increased significantly in group I-postC. The activity of SOD in plasma and lung tissues in?creased, but XOD and MDA decreased significantly(P<0.05). The mild damage of pathological changes were found. Conclu?sion Ischemic postconditioning can reduce the lung injury after limb ischemia reperfusion in rats, which may be related to the inhibition of lipid peroxidation.

AIM To evaluate the possible role of endogenous nitric oxide (NO) in the development of lung injury after hind limbs ischemia reperfusion (LIR), and the effect of taurine on endogenous NO on the model of lung injury following LIR. METHODS Wistar rats were divided into three groups: control group, ischemia reperfusion group (IR) and taurine+IR (Tau+IR). The changes of PaO 2 ,PaCO 2,lung index (LI) and lung permeability index (LPI) were observed. The content of malondialdehyde (MDA), NO and endothelin (ET) in both plasma and the lung as well as the content of nitric oxide synthase (NOS) and taurine in the lung were detected. The immunohistochemical method was used to detect level in the expression of NOS protein. RESULTS Taurine improved the pulmonary respiratory following LIR significantly, lightened lung edema, decreased the content of ET in both plasma and lung tissue, increased the content of NO in both plasma and lung tissue and promoted the level in the expression of NOS protein. CONCLUSION Using taurine may lighten lung injury following LIR and this protective effect may due to increasing the content of endogeneous NO and decreasing the level of ET.

Objective:To observe the inhibitory effect of ischemic postconditioning (I-postC) on the apoptosis of renal cells after limb ischemia reperfusion(LIR) in the rats, and to investigate the possible mechanisms. Methods:Thirty SD rats were randomly divided control group, ischemia-reperfusion group(IR group) and I-postC group(n=10).4 h ischemia and 4 h reperfusion with the rubber band in two hind limbs of the rats were performed to establish the models.In control group, the rubber band around the limb was loose and the blood flow was not blocked.As for I-postC group, before perfusion, 5 min ischemia and 5 min reperfusion were performed in the rats and repeated 3 times named I-post C.The levels of blood creatinine (Cr), blood urea nitrogen(BUN) and C-reactive protein (CRP) in plasma of the rats in various groups were measured by automatic biochemistry analyzer.The expressions of Bcl-2 protein and Bax protein in renal were detected by immunohistochemical method,and its quantitative results were observed with automatic image analysis system and the ratio of Bcl-2/Bax was calculated.The apoptotic cells in kidney tissue were determined by terminal-deoxynucleotidy1 transferase-mediated d-UTP nick end labeling (TUNEL) under laser scanning confocal microscope(LSCM).The ultrastructures of kidney tissue were observed under electron microscope.Results:Compared with control group, the levels of Cr,BUN and CRP in plasma of the rats in IR group and I-postC group were increased(P<0.05 or P<0.01);compared with IR group, the levels of Cr, BUN and CRP in plasma of the rats in I-postC group were decreased(P<0.01).Compared with control group,the expression levels Bax and Bcl-2 in kidney tissue of the rats in IR group and I-postC group were significantly increased (P<0.05 or P<0.01),and the ratios of Bcl-2/Bax were reduced(P<0.05);compared with IR group,the expression level of Bax in kidney tissue of the rats in I-postC group was decreased (P<0.05),the expression level of Bcl-2 was increased(P<0.01),and the ratio of Bcl-2/Bax was increased(P<0.05).Under laser confocal microscope,the number of apoptotic cells in kidney tissue of the rats in IR group was increased compared with control group;the number of apoptotic cells in I-postC group was decreased compared with IR group.Under transmission electron microscope,the changes in IR group were found as follows: renal proximal convoluted tubule epithelial cell nucleus vacuoles,increased lysosome and dense particle deposition, some mitochondria crest fracture or fuzzy;irregular and fusion, glomerular podocyte protuberance,mitochondrial cristae fracture and reducetion with vacuoles, rough endoplasmic reticulum expansion;the damage levels of renal tubular epithelial cells and glomerulus in I-postC group were improved compared with IR group.Conclusion: Limb ischemia reperfusion can induce the apoptosis of renal cells, I-postC can inhibit the apoptosis of renal cells,and it would be helpful to improve the kidney function.

AIM: To investingate the potential role of apoptosis in the development of acute lung injury(ALI) following limbs ischemia-reperfusion(LIR) in rats and the effects of raurine. METHODS: The model of LIB injury in rats was made. By using TUNEL, electrophoresis, reverse-transcription polymerase chain reaction(RT-PCR) and immunohistochemistry techniques, pulmonary apoptosis, Fas/FasL expressions and Ca~(2+), reactive oxygen species (ROS),the ratio of DNA double chain in tissue were detected in different groups.RESULTS: The rapid appearance of apoptosis in alveolar epithelial cells and pulmonary vascular endothelial cells were observed after LIR in rats. The ratio of DNA double chain decreased and tissue Ca~(2+) increased. The expression of Fas/FasL mRNA and protein was up-regulated in lung tissue of rats after LIR, which was related to the elevation of alveolar epithelial cells and pulmonary vascular endothelial cell apoptosis. Taurine decreased alveolar epithelial cell and pulmonary vascular endothelial cell apoptosis not by down-regulating expression of Fas/FasL system. CONCLUSIONS: These results suggest that the excessive apoptosis and Fas/FasL system expression may play a role in the pathogensis of ALI following LIB in rats, and taurine decreases alveolar epithelial cell and pulmonary vascular endothelial cell apoptosis.

BACKGROUND: Limb ischemia reperfusion (LIR) as a stressor leads to gastric mucosal injury, and then results in the occurrence of stress ulcer.OBJECTIVE: To observe the effects of LIR on gastric mucosal injury, investigate part of the mechanism, and the role of several transient limb ischemia in the occurrence of gastric mucosal injury.DESIGN: A randomized grouping design and controlled animal experiment.SETTING: Department of Pathophysiology of North China Coal Medical College.MATERIALS: The experiment was carried out in the pathophysiological laboratory of North China Coal Medical College from January to June 2002. Fifty-four healthy adult male Wistar rats were randomly divided into three groups with 18 rats in each group. Ischemia reperfusion (I/R) group: The rats were duplicated into models according to the Rosenthal method that under superficial anesthesia with ether, the roots of both hindlimbs were ligated by wrapping with rubber strap, blood flow was blocked for 4 hours and then recovered to perfusion for 4 hours, and finally killed by bleeding from abdominal aorta. Ischemic preconditioning group: Before model establishment, blood flow of both hindlimbs was blocked for 5 minutes, and then recovered to perfusion for 5 minutes, which was repeated for four times, and the following operations were the same as those in the I/R group. Control group: The operations were the same as those in the I/R group,but both hindlimbs were ligated at relaxation without blocking the blood flow.METHODS: Sections of gastric mucosa were prepared, and then observed under light microscope and electron microscope, and the index of gastric mucosal injury was determined according to the Guth standard. The colorimetric assay was performed with 721 spectrophotometer at 650 nm, and the amount of gastric combining mucus was calculated.Meanwhile, the blood flow of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus, content of nitric oxide in plasma and gastric tissue and activity of nitric oxide synthase (NOS) in gastric mucosa were determined.MAIN OUTCOME MEASURES: Index of gastric mucosal injury, amount of gastric combining mucus, blood flow of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus, contents of nitric oxide in plasma and gastric tissue and NOS activity in gastric mucosa.RESULTS: All the 54 rats were involved in the analysis of results. ① In the I/R group, gastric mucosal injury was serious, edema, hyperemia, erosion and disintegration of gland of mucosal glands were observed, infiltration of inflammatory cells (formation of ulcer) was observed in basal and inferior mucosa. In the ischemic preconditioning group, the gastric mucosa was complete, and the damaged severity was milder than that in the I/R group; Under electron microscope, the organell structures of gastric parietal and chief cells were incomplete and destroyed. The cell injuries in the ischemic preconditioning group were milder than those in the I/R group (index of injury: 18.00±10.71, 34.00±15.01, P＜ 0.01). ② The blood flow and combining mucosal amount of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus in the ischemic preconditioning group and I/R group were all obviously lower than those in the control group [(2.12±0.56), (10.84±2.56), (25.52±2.97) mL/(kg·h); (2.01±0.91), (2.79±0.73), (3.99±0.87) mg;(7.68±1.95), (9.74±1.04), (11.98±1.98) mg/g; (3.83±1.18), (5.42±0.47), (5.76±1.21) mg/g, P ＜ 0.05, 0.01], those the above indexes were all higher in the ischemic preconditioning group than in the I/R group. ③ The contents of nitric oxide in plasma and gastric tissue and NOS activity in gastric mucosa in the ischemic preconditioning group and I/R group were significantly lower than those in the control group [(250.0±5.6), (270.0±11.3), (210.0±7.4) μmol/L; (9.34±0.67), (11.34±1.00), (7.50±0.67) μ kat/g, P ＜ 0.01], those were also signficantly higher in the ischemic preconditioning group than in the I/R group.CONCLUSION: As a stressor, LIR can lead to gastric mucosal injury, and cause stress ulcer.Ischemic preconditioning can alleviate the gastric mucosal injury following LIR

Objective To investigate the effect of mitochondrial fission on the function of pancreatic β cells.Methods INS-1 stable cell lines allowing inducible expression of either wild-type dynamin-related protein 1 (Drp-1 WT)or its dominant-negative mutant(Drp-1 K38A)were used.The effect of mitochondrial fission on the function of pancreatic β cells were investigated under different concentrations of glucose.Results There were increased mitochondrial fission and disintegration of the mitochondrial reticulum into multiple punctiform organelles in Drp-1 WT cells induced with doxycycline under high glucose condition.Insulin secretion(P<0.01),mitochondrial membrane potential(P<0.05),and ATP content(P<0.05)were decreased and cytochrome C expression was increased after the expression of Drp-1 WT under high glucose condition while these changes were markedly mild in Drp-1 K38A expression cells.Conclusion The increased mitochondrial fission inhibits pancreatic β cell function.

Objective To observe changes of the pancreas after limb ischemia reperfusion, and the protective effect of taurine (Tau) postconditioning. Methods Twenty-four male SD rats were randomly divided into control group (Control), limb ischemia reperfusion (LIR) group, and taurine postconditioning (Tau) group (n=8 for each group). Plasma contents of xanthine oxidase (XOD), malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD), pancreatic amylase (AMS), pancreatic lipase (LPS) and trypsin were detected in three groups. Morphological changes of the pancreas were observed using optical microscopy. The expressions of anti-C/enhancer-binding protein homologous protein (CHOP) in pancreas were analyzed by immunohistochemistry assay. TUNEL staining was performed to estimate the apoptosis of pancre-atic cells. Results Compared with the control group and Tau group, plasma contents of MDA, XOD, ROS, AMS, LPS, and trypsin were significantly increased in LIR group, but the level of SOD was significantly lower in LIR group ( P<0.05). HE staining showed that acinar structure was disrupted , pancreatic lobule gap widened, stromal vascular dilatation and conges-tion were observed in LIR group. The perivascular infiltration of inflammatory cells appeared, islet cells were damaged with irregular islet. The immunohistochemical analysis showed the increased expression of CHOP in pancreas in LIR group than that of Tau group. And the pancreatic apoptosis was enhanced in LIR group detected by TUNEL staining. Conclusion Tau-rine postconditioning can ameliorate pancreatic injury following limb ischemia reperfusion, which may be related to the inhi-bition of oxidative stress, down-regulation of CHOP expression, thereby reducing endoplasmic reticulum stress-induced apoptosis.

Objective To investigate the influence and mechanism of erythropoietin (EPO) in renal blood flow after limb ischemia reperfusion (LIR). Methods Thirty male SD rats were randomly divided into control group, LIR group and EPO+LIR group with ten in each group. The values of renal blood flow, plasma creatinine (Cr), urea nitrogen (BUN) content in plasma, kidney tissue wet to dry ratio (W/D), nitric oxide (NO), nitric oxide synthase (NOS) and endothelin-1 (ET-1) in re-nal tissue were detected in three groups. The immunohistochemistry assay was used to detect the expression of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) in renal tissue. The morphological changes of renal tissue were observed with light microscope. Results The renal blood flow was significantly decreased, while the val-ues of Cr, BUN, W/D, NO, ET-1, NOS, expressions of ICAM-1 and VCAM-1 was significantly increased in LIR group than those of control group (P<0.05). Broaden interstitial and infiltration of inflammatory cells were observed in the renal tissue under light microscope. In the EPO+LIR group, the renal blood flow increased, the values of Cr, BUN, W/D, NO, ET-1 and NOS, expressions of ICAM-1 and VCAM-1 decreased significantly compared with those of LIR group (P<0.05). The patho-logical changes were alleviated in EPO+LIR group. Conclusion EPO can improve renal function, increase renal blood flow in rats after LIR. The mechanism may be related to the decreased edema, changed renal vasomotor function and decreased in-flammation.

Aim To investigate the effect of L-arginine(L-Arg) on myocardium in rat which suffered from limb ischemia-reperfusion.Methods Models of limb ischemia reperfusion were made by tourniquet methods.L-Arg(150 mg?kg-1) were intravascularly injected before reperfusion.Contents of malondialdehyde(MDA),myeloperoxidase(MPO) and tumour necrosis factor(TNF-?) in myocardium were measured.Levels of creatine kinase(CK),creatine kinase MB isoenzyme(CK-MB) and nitric oxide(NO) in plasma were deter-mined.The mean arterial pressure(MAP,left venteicular systolic pressure(LVSP),maximal rise rate of left venteicular pressure(dp/dtmax)and the maximal fall rate of left venteicular pressure(-dp/dtmax)were monitored.Morphologic changes of myocardium were evaluated after reperfusion.Results After rats' limbs suffering from ischemia-reperfusion,levels of MDA,MPO and TNF-? in myocardium,CK,CK-MB and NO in plasma increased differently(P