褪黑素对大鼠肝缺血再灌注损伤的保护作用

Protective effects of melatonin on hepatic ischemia reperfusion injury in rats

目的观察褪黑素（Mel）对大鼠肝组织Caspase-3表达的影响及对肝缺血再灌注损伤的保护作用。方法将72只Wistar大鼠，随机分为褪黑素处理3、6、12、24h组（Mel组），同样乙醇溶媒对照组（Alc组）和生理盐水对照组（NS组）也分别按3、6、12、24h各自分为4组，总共为12组。建立肝缺血再灌注损伤模型，于不同时点测定血清肝组织生化酶：ALT、AKP、对肝组织进行Caspase-3免疫组织化学染色。结果ALT在再灌注后各时点Mel组均显著低于Alc及Ns对照组（P〈0．05），AKP在再灌注后6、12、24h，Mel组显著低于Alc及NS对照组（P〈0．05），Mel组再灌注后各时点的Caspase-3染色阳性细胞率均显著低于对照组（Alc组和NS组，P〈0．05），以上各项指标在各时点Alc组与NS组比较差异无统计学意义（P〉0．05）。结论Mel能够减轻大鼠肝缺血再灌注损伤时的肝功能损害，抑制肝细胞Caspase-3的表达，减少肝细胞凋亡，对大鼠肝脏缺血再灌注损伤具有保护作用。

Objective To investigate the protective effects of melatonin （Mel） on hepatic ische- mia-reperfusion injury in rats. Methods Seventy-two healthy male Wistar rats （6-7 weeks old ） were randomly divided into 12 groups：Mel exposured group （Mel） ,alcohol solvent control group （Alc） and saline control group （NS） ,and each of them into 4 subgroups of 3,6,12 and 24 h after treatment. The partial hepatic ischemia-reperfusion injury models were established, and the enzyme levels in serum were deter- mined：including alanine aminotransferase （ALT） and alkaline phosphatase （AKP）. The expression of caspase-3 was detected in liver tissues by immunohistochemical stain, and the apoptosis of the hepatic cells by electron microscopy. Results The levels of ALT in Mel group were significantly lower than in Ale and NS groups （ P 〈 0.05 ）. The levels of AKP in Mel group determined at 6th, 12th and 24th h were significantly lower than in Alc and NS groups （ P 〈 0.05 ）. The expression of caspase-3 in Mel group was markedly lower than in Alc and NS groups （ P 〈 0.05 ）. There were no significant differences in the above results between Ale and NS groups. More apoptotic cells were observed in Acl and NS group than in Mel group. Conclusion Mel can reduce the hepatic injury due to the ischemia-reperfusion in rats,inhibit the expression of caspase-3 ,and alleviate the apoptosis of the hepatic cells. Mel can protect the ischema-reper- fusion injury of hepatic cells.