PPARβ/δ induced HSC proliferation in fibrotic mouse liver. A) Mouse liver sections were double-immunostained with antibodies against Ki67 (proliferation marker, red) and α-SMA(activated HSC marker, green). Nuclei were stained with DAPI (blue). Mice were treated with CCl4 or CCl4/GW501516 for 6 weeks. Sections are representative of 6 mice in each treatment group. Scale bar: 100 μm. B) qRT-PCR analysis shows Desmin and α-SMA mRNA expression after 6 weeks of the indicated treatments in wild type and PPARβ/δ KO mice. Results are means ± SEM of triplicate experiments (n=6). * = p<0.05, Student's t-test.