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Objective To observe the effects of intermittent hypoxic preconditioning on the expression of apoptosis-related EPO after 70％ hepatectomy combined with ischemia-reperfusion injury.Methods One hundred and twenty healthy SD rats of clean grade,simple random divided into 3 groups:Sham operation group of 40 rats ; Pure major hepatic resection group was 40 (Major hepatectomy,MH),namely in the hepatic portal blocking liver resection of the left and middle lobes,hepatic portal blocking 20 min ; intermittent hypoxia preconditioning group 40 (Intermittent hypoxia preconditioning,IHP group).Results MH group,S group,IHP group,EPO level in three experimental groups in postoperative residual liver tissue in rats with significant difference (P ＜ 0.05),Intermittent hypoxia preconditioning group of residual liver EPO content was significantly higher than that of simple hepatic resection group 40.Conclusion Intermittent hypoxia preconditioning can promote the expression of residual liver after hepatectomy in EPO.
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Objective To explore the impact and significance of hypoxia preconditioning on the expression of cytochrome C and caspase 3 protein in rats after hepatic resection.Methods A hepatectomy model was used to study the ischemia reperfusion injury in hepatic resection.Sprague-Dawley rats were randomly divided into the following three groups:normal control (NC) group,hepatic resection(HR) group,and hypoxia preconditioning (HP) group,there were twenty four rats in each group.HP Group was given an 10％ oxygen-mixed gas for 90 minutes before the operation.At 1,6,12 and 24 hours after the operation,the rats were killed and the following tests were conducted:(1) Liver tissue was sampled to observe the expression of cytochrome C and caspase 3 protein; (2) blood was drawn to conduct a chemical examination; (3) Liver tissue and morphology was observed by transmission electron microscopy.Results The serum levels of ALT and AST in HP group were significantly lower than that of HR group (P＜0.05) at 1,6,12 and 24 hours after the hepatic resection.In each time,liver function of the HP group was significantly better than the HR group; The expression of cytochrome C and caspase 3 protein was decreased significantly in HP group at each measurement point.Hepatic cells in HR group showed typical apoptosis signs under transmission electron microscopy (TEM),but no apoptosis was found in HP group.Conclusion HP has marked inhibition to apoptosis by down-regulating the expression of Cyt C and Caspase-3protein and protection to chondrosomes after a hepatic resection.
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Objective To investigate the effects of intermittent hypoxic preconditioning on residual liver regeneration after parital hepatectomy in rats.Methods Fifty-four Sprague-Dawley rats were randomly divided into 3 groups (each group contained eighteen animals):sham operation group (SO group),parital hepatectomy group (PH group)and intermittent hypoxic preconditioning group (IHP group).The rats in PH group underwent the left and middle lobectomy of liver(70％ hepatectomy).The rats in IHP group were exposed to hypoxic environment of 10％ oxygen for 1 h/d.And after a week,the rats underwent parital hepatectomy.Six rats in each group were sacrificed respectively on postoperative day 1,3 and 5 (POD 1,3 and 5).The resected liver and the regenerated liver were weighed to calculate liver regeneration degree and regeneration index.The values of alaninea minotransferase (ALT) and aspartate aminotransferase (AST) in the inferior vena venous blood were examined by automatic biochemical analyzer.The positive ratio of hepatocellular proliferating cell nuclear antigen (PCNA) in the residual liver was investigated immunohistochemically.Results The degree and index of liver regeneration in IHP group were respectively higher than those in PH group on POD 1 and 3(P ＜0.05),but there were no statistical differences between the two groups on POD 5.The levels of ALT and AST in PH and IHP group began to decline after surgery,but they remined higher than those in SO group.Moreover,the ALT and AST levels in IHP group were significantly lower than those in PH group on POD 1 (P ＜0.05).The positive ratios of hepatocellular PCNA were respectively higher than those in SO and PH group on POD 1,3 and 5 (P ＜ 0.05).Conclusions To some extent,preoperative intermittent hypoxic preconditioning could prevent hepatocellular damage after parital hepatectomy,what is more,it also could promote the remnant liver regeneration.But the mechanism still needs to be studied furter.
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Objective To observe the effects of intermittent hypoxic preconditioning on the expression of apoptosis-related Bcl-2 and Bax protein after 70％ hepatectomy combined with ischemia-reperfusion injury.Methods A total of fifty-four SD rats were randomly divided into three groups (n =18).Partial hepatectomy hroup (PH Group):Rats underwent the left and middle lobectomy of liver(70％ hepatectomy).Ischemia reperfusion group (IR group):The left and middle lobes of liver were resected during the occlusion of the hepatoduodenal ligament for 20 minutes.Residual liver underwent the process of ischemia-reperfusion.Intermittent hypoxia preconditioning group (IHP group):rats were exposed to hypoxic environment of 10％ oxygen for 1 h/d.After 7 consecutive days,the left and middle lobes of liver were resected under the portal triad clamping.At 12,24 and 48 hours after the operation,the rats were killed and detected.The serum levels of ALT and AST were determined by automatic biochemical analyzer.The expression of Bcl-2 and Bax protein in liver tissue were measured by immunohistochemistry.Results At each time point after surgery,the serum levels of ALT and AST in IR group and IHP group were higher than that of PH group,and IHP group were lower than in IR group.Compared with IR group,the expression of Bcl2 protein significantly increased and Bax protein expression significantly decreased in IHP group.All these differences were statistically significant (P ＜ 0.05).Conclusions Intermittent hypoxic preconditioning might protect residual liver against ischemia reperfusion injury,through increasing the expression of Bcl-2 protein and reducing the expression of Bcl-2 protein to decrease liver cell apoptosis.
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Objective To investigate the effect of Heat shock protein 70 induced by hypoxic precondition on apoptosis of the remnant livers after the hepatectomy of transplanted hepatic cancer models in SD rants and it's possible mechanisms.Methods Sixty SD rats of transplanted hepatic cancer models were divided into group A (sham operation group),group B (IR + hepatectomy group),and group C (hypoxia precondition + IR + hepatectomy group),with 20 rats in each group.C group was given 10％ oxygen atmosphere for 90 minutes before operation,In 15 minutes of hepatic vascular occlusion with pringle method,Left lateral of liver which tumor was located was resected.At 1,8,12,24 hours after operation,Five rats of each group were killed respectively,then the remnant liver tissues were sampled to measured the hepatocytes apoptosis rate with flow cytometry,expression of heat shock protein 70 (HSP70) and Bax were detected by Western blotting.The serum AST and ALT activities were measured by an automatic analyzer.The histological changes of the hepatocytes were also observed by optical microscopy.All the data were statistically analyzed.Results (1) Compared with A and B group,the HSP70 expression increased obviously in C group at each time point (all P ＜ 0.05).The protein showed a weak expression in group A and B group,while the index had no significant differences between two groups (P ＞ 0.05).(2) In B group compared with A group,the expression of Bax and the hepatocytes apoptosis rate were significantly increased (all P ＜ 0.01 or P ＜0.05).However,amplitudes of the above changes in C group were significantly lower than those of B group (all P ＜ 0.05).(3)The liver function was improved in group HP.The pathological examination showed that the liver tissues in A group were general normal and in C group were showed mild changes,but in B group presented evident pathological changes.Conclusions HP can protect against ischemia-reperfusion injury after the hepatectomy of transplanted hepatic cancer models in SD rants,one of possible mechanisms is that HP can induce HSP70 expression at great intensity,which may decrease expression of Bax protein and the apoptosis of hepatocytes.
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Hypoxic preconditioning improves organism in stress response such as operation.This dissertation expound the effects of hypoxic preconditioning on hepatic carcinoma after hepatic resection.Hypoxic preconditioning protect remainder hepatocyte from ischemia reperfusion injury in the remaining liver by regulating HIF-1,nuclear factor-kappa B and being kind to our mitochondria; remote-ectopic hypoxic preconditioning and cross-pluripotential hypoxic preconditioning preserve residual liver.Hypoxic preconditioning can relieve liver from ischemia reperfusion injury after hepatocellular carcinoma hepatectomy,but no clear evidence demonstrate it improve residual liver regeneration.This need further experimental study.
