生长抑素对瘦素诱导肝星状细胞的活化增殖、PTP1B表达及JAK2-STAT3通路的影响

Effect of somatostatin on leptin-induced activation,proliferation,PTP1B expression and JAK2-STAT3 signaling of hepatic stellate cells

目的研究生长抑素对瘦素诱导大鼠肝星状细胞(HSC)的活化增殖、蛋白酪氨酸磷酸酶1B(PTP1B)表达及JAK2-STAT3通路的影响,探讨生长抑素抗肝纤维化的相关机制。方法以重组大鼠瘦素作用于HSC-T6细胞(100 ng/ml),同时加入各浓度的生长抑素(10-6、10-7、10-8、10-9、10-10mol/L)。在处理24 h后,采用CCK-8法检测HSC增殖的变化,免疫细胞化学检测p-JAK2及p-STAT3蛋白表达,RT-PCR法检测α-平滑肌肌动蛋白(α-SMA)和PTP1B的mRNA表达。结果 CCK-8法显示生长抑素可通过剂量依赖方式抑制瘦素诱导的HSC-T6细胞增殖(P<0.05);免疫细胞化学检测显示,生长抑素组HSC-T6细胞质p-JAK2及细胞核内p-STAT3蛋白表达明显低于瘦素对照组(P<0.05);RT-PCR法检测生长抑素干预组HSCα-SMA mRNA的表达较瘦素对照组及空白对照组明显降低(P<0.05),而PTP1B的mRNA表达量升高(P<0.05)。结论生长抑素能上调PTP1B的表达,阻断瘦素在HSC内JAK2-STAT3信号通路的转导,并且抑制瘦素诱导HSC的活化与增殖。

Objective To investigate the effect of somatostatin on leptin-induced activation, proliferation, PTP1B expression and JAK2-STAT3 signaling of rat hepatic stellate cells （ HSC-T6 ） . Methods HSC-T6 cells were trea-ted with recombinant rat leptin （100 ng/ml） and various concentrations of somatostatin （10 -6,10 -7,10 -8,10 -9, 10 -10 mol/L）. After incubation for 24 h, the cell proliferation rates of the groups were determined by CCK-8. Im-munocytochemical staining assay was applied to evaluate phosphorylation of Janus kinase 2 （ JAK2 ） and protein ex-pression of signal transducers and activators of transcription 3 （ STAT3 ） . The mRNA expression of α-SMA and PTP1B was evaluated by RT-PCR. Results With CCK-8, somatostatin could promote leptin-induced proliferation of hepatic stellate cells in a dose-adependent manner （ P〈0.05 ） . The expressions of cytoplasmic p-JAK2 and nu-cleic p-STAT3 after somatostatin intervention were significantly lower than that of the leptin control group （ P 〈0.05）. Compared with the group with leptin,α-SMA mRNA of somatostatin group was significantly down-regulated after the treatment （ P〈0.05 ） , while PTP1 B mRNA expression was significantly increased （ P〈0.05 ） . Conclu-sion Somatostatin up-regulates PTP1B expression, inhibits JAK2-STAT3 signal transduction in HSC and the cell activation and proliferation induced by leptin.