| PrefaceLiver transplantation has become an important and effective method for treating terminal liver diseases, liver neoplasms and some congenital hepatic illnesses. Whereas ischemia - reperfusion injury (I/R I) , whose mechanism is not completely demonstrated, is one of the main causes responsible for liver transplantation failure. Melatonin ( Mel) is a kind of nerve incretion secreted by pineal gland cells. Its becoming one of the research hotspots owning to the complex physiological and pharmacological effects on multiple systems and organs. Domestic reports about Mel on liver I/R I are rare. In this study, in order to clarify the influence and mechanism of Mel on I/R I in rats, I/R I models were set up, samples according to different time after reperfusion were collected, hepatic enzyme series ( ALT, AST, AKP ) in serum, anti - oxidase series ( SOD, GSH. px ) and terminal productions of lipid peroxidation ( LPO) in liver tissue were determined. Meanwhile, hematoxylin - eosin ( H. E ) and imrnunohistochemical staining were employed to observe the morphologic change under light microscope as well as liver nuclei and organ cells under electron microscope. Mechanism of the protective effects of Mel on liver I/R I was discussed in sub - cellular level and evidence that Mel would beapplied clinically to liver surgery was provided as a result.Material and Method1. Material150 male Wistar rats weighing 190 - 210 grams, aging 6 -7weeks were divided into three groups at random: Mel exposure group, alcohol solvent control group and saline control group. According to Kobayashi, we blocked up the left branches of portal vein, hepatic artery, hepatic duct for 60 min and then opened them to establish liver I/R I models in rats. In each group, samples were collected in 0. 5h, Ih, 6. Oh, 12. Oh, 24. Oh after reperfusion respectively. One gram of Mel was purchased from Sigma company and was stored in low temperature after being dissolved by alcohol and saline. 20mg/ kg of Mel was injected IP in rats 30 min before experimentation. The duplicate concentration of alcohol and the same volume of saline were injected in control groups as substitution.2. Method1) Measurement of hepatic enzyme series (ALT, AST, AKP) in serum by auto biochemical analyzer.2) Measurement of anti - oxidase series (SOD, GSH. px) and terminal productions of lipid peroxidationin (MDA) in liver tissue.3 ) Pathological examination of I/R I liver tissue.4 ) Immunohistochemical straining of ICAM -1.5 ) Observation of hepatic cells under electron microscope.6) Statistics: Data was expressed as X S. Statistics analysis was performed with One - Way analysis of variation ( ANOVA) and SNK test with the help of software SPSS 11.0Result1. Hepatic enzyme series in serum in rats;1. 1 The level of ALT measured in various time after reperfusion in Mel group was totally significantly lower than that in alcohol and saline control groups corresponding ( p <0.05).1.2 The level of AST measured in 6. Oh and 12. Oh after reperfusion in Mel group was significantly lower than that in alcohol and saline control groups corresponding( p <0. 05).1. 3 The level of AKP measured in 24. Oh after reperfusion in Mel group was significantly lower than that in alcohol and saline control groups corresponding( p < 0.05 ) .The difference of the above three enzymes corresponding between the two control groups was not significant.2. Measurement of anti - oxidase series and terminal productions of lipid peroxidationin in liver tissue.2. 1 The level of MDA measured in 6. Oh, 12. Oh, 24. Oh after reperfusion in Mel group was significantly higher than that in alcohol and saline control groups corresponding( p <0. 05).2. 2 The level of SOD measured in 12. Oh, 24. Oh after reperfusion in Mel group was significantly higher than that in alcohol and saline control groups corresponding( p <0.05).2.3 The level of GSH. px measured in 12. Oh, 24. Oh after reperfusion in Mel group was significantly higher than that in alcohol and...
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