Induction of proliferation and activation of rat hepatic stellate cells via high glucose and high insulin

OBJECTIVE: To further investigate the occurrence mechanism of diabetic hepatic fibrosis through observing the effects of insulin and glucose in different concentrations on hepatic stellate cell (HSC) proliferation, and mRNA expressions of transforming growth factor-beta 1 (TGF-beta 1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in rats, so as to provide a theoretical and experimental basis for the occurrence, prevention and treatment of diabetic hepatic fibrosis (HF). MATERIALS AND METHODS: The HSCs in rats were cultured in vitro with high glucose alone and high glucose + high insulin as the stimulating factors and mannitol as the high osmotic pressure control. After the above 10 groups of HSC were cultured for some time, the absorbance value of each group was determined using the Cell Counting Kit-8 (CCK-8) to clarify the number of proliferative HSC. Moreover, the count per minute (Cpm) of DNA in HSC was detected via the 3H-thymidine incorporation (3H-TDR incorporation) to clear the proliferation status of HSC. Finally, the mRNA expressions of TGF-beta 1 and TIMP-1 in HSC in each group were detected via Real-time fluorescence quantitative polymerase chain reaction (RT-FQ-PCR). RESULTS: Both HSC proliferation and DNA synthesis were increased in a glucose concentration-dependent manner, while the HSC proliferation and DNA synthesis in glucose groups with insulin were significantly higher than those in glucose groups without insulin (p<0.05). The DNA synthesis in insulin + mannitol group was higher than that in insulin + normal glucose group. The mRNA level in TGF-beta 1 in glucose groups with insulin was decreased, but that in TIMP-1 was increased. CONCLUSIONS: Both high glucose and high insulin can induce the HSC proliferation, and high insulin can further activate HSC and promote the progression of hepatic fibrosis course.