Hepatic fibrosis represents a process of healing and scarring in response to chronic liver injury. Interleukin-10 (IL-10) is a cytokine that downregulates the proinflammatory response and has a modulatory effect on hepatic fibrogenesis. The aim of this study was to investigate whether IL-10 gene therapy possesses anti-hepatic fibrogenesis in mice. Liver fibrosis was induced by long-term thioacetamide administration in mice. Human IL-10 expression plasmid was delivered via electroporation after liver fibrosis established. IL-10 gene therapy reversed hepatic fibrosis and prevented cell apoptosis in a thioacetamide-treated liver. RT-PCR revealed IL-10 gene therapy to reduce liver transforming growth factor-beta 1, tumor necrosis factor-alpha, collagen alpha 1, cell adhesion molecule, and tissue inhibitors of metalloproteinase mRNA upregulation. Following gene transfer, the activation of alpha-smooth muscle actin and cyclooxygenase-2 was significantly attenuated. In brief, IL-10 gene therapy might be an effective therapeutic reagent for liver fibrosis with potential future clinical applications. (c) 2005 Elsevier Inc. All rights reserved.