褪黑素对大鼠肝脏缺血再灌注损伤的影响

目的探讨褪黑素（MT）保护大鼠肝缺血再灌注损伤的机制。方法采取大鼠第一肝门阻断的缺血再灌注模型,将健康雄性SD大鼠64只随机分为两组：对照组和MT组,观察每组动物的病理切片,分别检测血浆丙氨酸氨基转移酶（ALT）、乳酸脱氢酶（LDH）及肝组织匀浆中丙二醛（MDA）、超氧化物歧化酶（SOD）、一氧化氮（NO）的含量,免疫组化测定诱导型NO合酶（iNOS）的表达。结果肝脏缺血再灌注后,有明显的病理损伤改变。MT组再灌注2 h、4 h血清ALT、LDH、肝组织匀浆中MDA和SOD含量与对照组相比均明显降低（均P〈0.01）,MT组iN-OS表达明显低于对照组（P〈0.01）。结论自由基产生过多是肝脏缺血再灌注损伤初期的主要原因,给予MT预处理可通过调节iNOS和SOD来降低MDA、NO水平,从而减轻肝脏损伤。

Effect of Melatonin on Hepatic Ischemia and Reperfusion Injury in Rats

Objective To investigate the effect of melatonin（MT） on hepatic ischemia and reperfusion in rats.Methods Sixty four healthy male SD rats were randomly divided into MT pretreatment group and control group.Serum alanine aminotransferase（ALT）,lactate dehydrogenase（LDH） were determined at the different times.Liver tissues were taken for determination of malondialdehyde（MDA）levels,superoxide dismutase（SOD）and nitrite oxide（NO）.Expression of inductive NO synthase（iNOS）were evaluated immunohistochemistry.Results There was histologic evidence of liver injury.At 2h,4h of reperfusion,ALT,LDH,MDA and NO in the control group increased compared with MT pretreatment group（P0.01）.Moreover,iNOS staining was attenuated in control group compared with MT pretreatment group（P0.01）.Conclusions Reactive oxygen species are contributed to pathologic procedure of hepatic ischemia and reperfusion.MT pretreatment can reduce liver injury through reducing production of MDA and NO and decreasing iNOS expression.