Improved anti-fibrotic effects by combined treat- ments of simvastatin and NS-398 in experimental liver fibrosis models

Abstract

Background/Aims: Efficient anti-fibrotic therapies are required for the treatment of liver cirrhosis. Hydroxymethylglu-taryl-coenzyme A reductase inhibitors (statins) and cyclooxygenase-2 (COX-2) inhibitors have been reported to have anti -fi-brotic effects. Here, we investigated whether combined treatment with a statin and a COX-2 inhibitor has synergistic anti -fi-brotic effects. Methods: The effects of treatment strategies incorporating both simvastatin and a COX-2 inhibitor, NS-398, were inves-tigated using an immortalized human hepatic stellate cell line (LX-2) and a hepatic fibrosis mouse model developed using thioacetamide (TAA) in drinking water. Cellular proliferation was investigated via 5-bromo-2-deoxyuridine uptake. Pro-and anti-apoptotic factors were investigated through Western blotting and real-time polymerase chain reaction analysis. Results: The evaluation of the anti-proliferative effects on LX-2 cells showed that the observed effects were more pro-nounced with combination therapy than with single-drug therapy. Moreover, hepatic fibrosis and collagen deposition de-creased significantly in TAA-treated mice in response to the combined treatment strategy. The mechanisms underlying the anti-fibrotic effects of the combination therapy were investigated. The effects of the combination therapy were correlated with increased expression levels of extracellular signal-regulated kinase 1/2 signaling molecules, upregulation of the Bax/Bcl-2 signaling pathway, inhibition of the transforming growth factor-13 signaling pathway, and inhibition of tissue inhibitor of matrix metalloproteinases 1 and 2. Conclusions: The combination of simvastatin and NS-398 resulted in a synergistic anti-fibrotic effect through multiple pathways. These findings offer a theoretical insight into the possible clinical application of this strategy for the treatment of advanced liver diseases with hepatic fibrosis.