小干扰RNA沉默瘦素揭示了瘦素在大鼠肝纤维化中的作用

Silencing leptin with short interfering RNA reveals the role of leptin in rat firrosis

目的观察靶向瘦素(leptin)小干扰RNA(interference,siRNA)真核细胞表达质粒对大鼠肝纤维化的影响。方法采用已构建的重组Leptin-siRNA真核细胞表达质粒,用脂质体包埋法通过腹腔注射将其导入大鼠肝纤维化模型体内。通过HE染色观察肝脏病理形态学变化;Western Blot检测leptin、I型胶原和STAT3蛋白表达变化;半定量RT-PCR检测leptin mRNA表达。结果与正常对照组相比,肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)肝纤维化程度较重,纤维化评分多为Ⅳ级(P<0.01),同时肝脏leptin、I型胶原和STAT3含量明显上升(P<0.05);而与肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)比,leptin-siRNA质粒转染组(The CCl4(+)L)肝纤维化程度减轻,纤维化程度多为Ⅰ-Ⅱ级,肝脏leptin、I型胶原和STAT3表达均显著抑制(P<0.05)。正常对照组和leptin-siRNA质粒组(The CCl4(+)L)在组织学及leptin、I型胶原和STAT3基因转录和表达水平无统计学差异(P>0.05)。结论 leptin-siRNA表达质粒降低I型胶原和STAT3含量、抑制leptin表达,阻抑肝纤维化;Leptin有望成为肝纤维化基因治疗的新靶位点。

Obj ective To observe the effects of leptin-siRNA expression plasmids on rat liver fibro-sis.Methods The constructed leptin-siRNA expression plasmids were injected into the abdominal cavity of rat liver fibrosis models by encapsulation with Lipofectmine 2000.The pathological grade was observed by HE staining.Leptin,collagen I and STAT3 were detected by Western blot.The mRNA expression of lep-tin was assessed by semi-RT-PCR .Results The fibrosis model CCl4 and CCl4(+)K groups showed severe fibrosis,including septal fibrosis,extensive bridging,and fatty degeneration.The expressions of leptin, collagen type I and STAT3 in mRNA and protein were also elevated in the livers from these groups(P<0. 05).Compared with the CCl4 and CCl4(+)K groups,the CCl4(+)L group showed good preservation of liver lobular architeture and only mild bridging fibrosis,accompanied by decreased expression of leptin, collagen type I and STAT3 in mRNA and protein(P<0.05).Semi-quantitative analysis of the fibrosis stage indicated that most rats in the model,CCl4 and CCl4(+)K groups were of S5.In contrast,most rats (93%)in the CCl4(+)L group were of stages S1 and S2.There was no significant difference between the normal control and CCl4(+)L groups(P>0.05).Conclusion The leptin-siRNA plasmid can decrease collagen I and STAT3,inhibit leptin,and attenuate hepatic fibrosis.Leptin may become a new gene thera-py target of liver fibrosis.