Effect of Hypoxia on the Activation and Visfatin Expression in Rat Hepatic Stellate Cells

Abstract

To investigate the effect of hypoxia on the visfatin and the expression of smooth muscle-actin (α-SMA) and hypoxia-inducible factor-1α (HIF-1α) in rat hepatic stellate cells (HSCs). Methods Rat primary HSCs were isolated from SD rats by in situ perfusion of collagenase and pronase and single-step Nycodenz density gradient centrifugation, and then cultured and activated. Completely activated primary HSCs were exposed to hypoxic conditions (37 ℃, 5% CO2, 1% O2,94%N2), or normoxic conditions (37 ℃, 5% CO2, 21% O2,74% N2), for 3, 6, 12 or 24 h respectively. The expression of α-SMA, the marker of HSC activation, and visfatin were assessed by Real time-PCR and Western blot. The Expression of HIF-1α was detected by Real time-PCR. Results HIF-1α mRNA in rat HSCs was induced after exposed to hypoxia for 3 h, and maintained elevated status up to 24 h. HSCs exposed to 1% O2 hypoxic conditions for 6 h increased α-SMA mRNA and protein expression. Visfatin mRNA expression was up-regulated after subjected to hypoxia for 12 h, and protein level was elevated after 6 h hypoxia. A positive linear correlation existed between α-SMA and visfatin expression in responsible to hypoxia 〔r=0.991 (genes) and r=0.968 (proteins),P<0.05〕. Conclusion Microcirculation impairment could significantly induce α-SMA and visfatin expression in rat HSCs, which might potentate the activation process of HSCs.

Keywords: Hepatic stellate cells, Hypoxia-inducible factor-1α, Visfatin α-smooth muscle actin