Abstract: Objective To investigate the effect of miR-200a mimic on transforming growth factor β1-mediated activation and collagen secretion of rat pancreatic stellate cells. Methods PSCs were isolated and cultured from pancreatic tissue and identified by desmin, GFAP and α-SMA immunofluorescence staining. PSCs of 2nd generation were divided into control group, TGF-β1 group, TGF-β1+miR-NC group and TGF-β1+miR-200a mimic group. The levels of a-SMA and collagen I protein were measured by Western blot and immunofluorescence staining. The mRNA levels of a-SMA and collagenⅠ and the expression of miR-200a were detected by quantitative real-time PCR. Results TGF-β1 can stimulate the activation of PSCs and promote collagen synthesis in time-dependment manner (P<0.05). After transfection of the mimic, treating with the same concentration of TGF-β1, the expressions of protein and mRNA of both a-SMA and collagen I decreased significantly (P<0.01). Conclusion Over-expression of miR-200a significantly attenuates a-SMA activity and further affects the collagen synthesis of TGF-β1-dependent activation of PSCs. The mechanisms may inhibit the biological effects of TGF-β1.

Key words: TGF-β1, PSCs, miR-200a, fibrosis