Explore The Molecular Mechanisms Of Somatostatin Inhibites The Proliferation And Extracellular Matrix Secretion Of Hepatic Stellate Cells Induced By Leptin

Objective: To investigate the influence of somatostatin on the proliferation and the matrix protein secretion of hepatic stellate cells(HSCs) induced by leptin;explore the regulatory effect of somatostatin on intracellular protein tyrosine enzyme 1 B(PTP1B)and the phosphorylation of protein JAK2/STAT3.Methods: Culture human hepatic stellate cell line(LX‐2)the effect of different concentrations(10‐6,10‐7,10‐8,10‐9mol/L) of somatostatin on the proliferation of activatied LX‐2 cells induced by leptin was detected with MTT assay.According to the outcome of MTT, select the appropriate concentration of somatostatin. LX‐2 cells were divided into ①.control group, ②.100 ng/ml leptin group, ③.100 ng/ml leptin+10‐6mol/L somatostatin group and ④.100 ng/ml leptin+10‐7mol/L somatostatin group. After 24 hours, the PTP1 B m RNA, TIMP‐1 m RNA,type I collagen m RNA were detected by RT‐PCR assay.Western blot analysis was applied to evaluate the protein expression of PTP1 B and the phosphorylation of Janus kinase2(JAK2) and signal transducers and activators of transcription 3(STAT3).And enzyme‐linked immunosorbent assay was used to detect production of I collagen in culture medium.Results:1. Somatostatin could promote leptin‐induced proliferation of LX‐2 cells in a dose‐adependent manner( P < 0.05); The highest inhibition ratio(29.29%) was the concentration of 10‐6mol/L in the group.2. ①. RT‐PCR: somatostatin can improve PTP1 B m RNA expression(P < 0.05) of activatied LX‐2 cells, and the higher does of somatostatin increased more obviouslycompared to the lower does(P < 0.05), somatostatin can reduce TIMP‐1 m RNA(P <0.05), but there is no difference between the two somatostatin groups(P >0.05).somatostatin can reduce type I collagen m RNA(P < 0.05) expression, and the higher does of somatostatin reduced more obviously compared to the lower does(P <0.05), ②. Western blot: somatostatin can improve PTP1 B protein(P < 0.05) and make the JAK2/STAT3 protein dephosphorylated(P < 0.05), at the same time, the higher somatostatin group reduce these factors more obviously than the low somatostatin group(P < 0.05), the higher concentration of somatostatin can increase PTP1 B obviously than the lower somatostatin group(P < 0.05). ③.ELISA: leptin can improve the expression of type I collagen protein obviously(P < 0.05),at the same time,somatostatin can reduce this factor(P < 0.05), and the higher concentration of somatostatin can reduce this obviously than the lower somatostatin group(P < 0.05).Conclusion:1. Somatostatin could suppress the proliferation of leptin‐induced LX‐2 in a dose‐adependent manner.2. Somatostatin up‐regulates PTP1 B expression, inhibits proliferation, JAK2/STAT3 signal transduction and reduces TIMP‐1, I collagen expression in actived LX‐2 cells induced by leptin.