ACTA1 and Hepatic fibrosis: This work proposes a new protocol for the induction of advanced liver fibrosis in rats by 24 doses of 200 mg/kg thioacetamide, which in our work produces low mortality and uses conventional tests and markers (METAVIR test, α-SMA, CD68, collagen type I, ALT, alkaline phosphatase, and others) to establish the stage of the disease and the regression of the fibrosis.