雌二醇对大鼠肝缺血再灌注损伤NOS表达的影响

Influence of estradiol on expression of nitric oxide synthase following hepatic ischemia reperfusion injury in rats

目的探讨雌激素对大鼠肝缺血再灌注损伤(HIRI)中诱生型一氧化氮合酶(iNOS)和内皮型一氧化氮合酶(eNOS)表达的影响及其作用机制。方法将48只Wistar大鼠分为4组:A组,雄性组;B组,卵巢去势组(OVX组);C组,雌性对照组(假手术组);D组,给予17β-雌二醇的卵巢去势组(OVX+E2组)。建立原位大鼠HIRI模型,观察大鼠肝缺血再灌注40min后6,12,24 h大鼠的血清雌二醇(E2)水平变化,同时采集肝组织标本,利用免疫组化方法观察肝细胞胞质一氧化氮合酶(NOS)表达情况。结果①各时点A组与B组E2水平较低,两组间比较无统计学差异(P>0.05)。C组E2水平增高,D组E2水平最高。A组与B组组间比较无差异,其余各组间比较均有显著差异(P<0.05)。②再灌注6 h各组肝细胞、枯否细胞均少许表达iNOS,肝窦内皮细胞均表达eNOS,再灌注12-24 h iNOS表达明显升高,eNOS表达明显降低;各时点NOS表达A组与B组比较、C组与D组比较无统计学差异(P>0.05),其余各组间比较均有显著差异(P<0.05)。结论大鼠HIRI后雌激素促进eNOS表达,抑制iNOS表达,可能是其减轻HIRI作用的机制之一。

Objective To investigate the influence of estrogen on the expression of inducible nitric oxide synthase （iNOS） and endothelial nitric oxide synthase （eNOS） in hepatocytes following rat hepatic ischemia-reperfusion injury （HIRI）, and to explore its mechanism to provide an experimental basis for treating HIRI. Methods Forty-eight rats were divided into 4 groups： male group （group A）; OVX group（group B）; female control group （false operative group, group C）; OVX ＋ E2 group（group D）. The rat models with HIRI were established. Changes of serum estradiol in blood serum of the rats were observed at hours 6, 12 and 24 after hepatic ischemia-reperfusion. Meanwhile, the expression of NOS in hepatocytes was detected with immunohistochemistry method. Results OThe estradiol levels of groups A and B were low at indicated times, and there was no significant difference between both （P 〉0.05）. The estradiol level in group C increased,and in group D it was the highest. There was significant difference between all the groups except between groups A and B （P〈0.05）. ②There was a little expression of iNOS in hepatocytes and Kupffer＇ s cell （KC） in each group at hour 6 after reperfusion, but there was expression of eNOS in hepatic sinusoidal endothelial cell （SEC）. The expression of iNOS increased significantly,but that of eNOS decreased significantly after 12 - 24 h reperfusion. There was significant difference between groups （ P 〈 0. 05 ） , but not between groups A and B,and between groups C and D （ P 〉0. 05 ） . Conclusion Estrogen promotes eNOS expression, inhibits iNOS expression after hepatic ischemia-reperfusion injury in rats. This may be one of mechanisms in which estrogen exerts liver-protection in hepatic ischemia-reperfusion injury in rats.