Elsevier

Laboratory Investigation

Volume 92, Issue 10, October 2012, Pages 1440-1450
Laboratory Investigation

Research Article
Atorvastatin inhibits proliferation and apoptosis, but induces senescence in hepatic myofibroblasts and thereby attenuates hepatic fibrosis in rats

https://doi.org/10.1038/labinvest.2012.106Get rights and content
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Abstract

Hepatic myofibroblasts (MFB) show increased proliferation, migration and collagen production, which are crucial for hepatic fibrogenesis. Atorvastatin treatment inhibits proliferation, apoptosis and cytokine production of MFB in bile duct-ligated (BDL) rats in vivo. Here, we have further investigated the underlying mechanisms. Primary rat hepatic stellate cells (HSC) were isolated and culture-activated to hepatic MFB. Following 3 days of incubation with atorvastatin (10−4, 10−5 and 10−6 M), transcription levels of profibrotic cytokines (transforming growth factor-β1, connective tissue growth factor and TIMP1) and procollagen Ia were analyzed by real time PCR. Proliferation was investigated by 5'-bromo-2'-deoxyuridine assays. α-Smooth muscle actin protein expression was examined by western blotting. Fluorescence-activated cell sorting analysis of Annexin V and propidium iodide were used to measure apoptosis. Furthermore, p21 western blotting and β-galactosidase staining were investigated in MFB as senescence markers. Subsequently, hepatic expression of desmin and senescence markers were analyzed in the livers of rats receiving atorvastatin (15 mg/kg*d) for 1 week starting 3 and 5 weeks after BDL. Atorvastatin inhibited the activation of HSC to MFB and decreased cytokine and collagen production in MFB in vitro. In addition, proliferation, cytokine and collagen production of MFB were reduced by atorvastatin. Atorvastatin initiated apoptosis at 10−4 M and attenuated it at 10−5 M. Atorvastatin induced p21 protein expression and β-galactosidase staining of MFB in vitro and in vivo. Atorvastatin elicits similiar effects on MFB as previously seen in vivo: it decreases MFB turnover and fibrogenesis. We suggest that a further mechanism explaining these effects is senescence of cells.

Keywords

cytokines
fibrogenesis
hepatic stellate cells
HMG-CoA reductase inhibitor
myofibroblasts
senescence

Cited by (0)

Atorvastatin prevents liver fibrosis and is also a beneficial treatment for established fibrosis. The mechanisms are twofold: the prevention of hepatic stellate cell (HSC) activation, and decreased cytokine and collagen production in previously activated HSCs. Furthermore, atorvastatin decreases turnover and induces senescence of activated HSCs and hepatic myofibroblasts in injured livers.