TGFB1 and Hepatic fibrosis: The team of Okuno showed that RA enhanced ECM production and exacerbated liver fibrosis by inducing the activation of TGF-β1, and the used dose in their study was greatly higher compared with the doses used in other studies [63–64], further demonstrating the unsuccessful application of RA in the treatment of liver fibrosis due to the hepatotoxicity caused by higher dose of RA.