Objective
This study investigated the immunoregulatory and protective roles of Yinchenhao decoction, a compound of Chinese herbal medicine, in a mouse model of concanavalin A (ConA)-induced chronic liver injury.
Methods
Female BalB/c mice were randomly divided into 4 groups: normal control, ConA model, ConA model treated with Yinchenhao decoction (400 mg/kg, orally), and ConA model treated with dexamethasone (0.5 mg/kg, orally). All treatments were given once a day for 28 d. Except of the normal control, mice received tail vein injection of ConA (10 mg/kg) on days 7, 14, 21, and 28, at 1 h after treatment with Yinchenhao decoction or dexamethasone or saline to induce chronic liver injury.
Results
Repeated ConA injection induced chronic liver injury, which was evidenced by inflammatory cell infiltration and necrosis, increased serum alanine aminotranferease activities, decreased albumin levels, and an imbalanced expression of immunoregulatory genes in the liver tissues including significantly enhanced interferon-γ, interleukin-4, monocyte chemotactic protein-1, and cluster of differentiation 163 mRNA levels, and reduced tumor necrosis factor-α and interleukin-6 mRNA levels. Treatment with Yinchenhao decoction significantly reversed the ConA-induced changes in immunoregulatory gene expression in the liver tissues, reduced serum alanine aminotranferease activity, enhanced serum albumin level, and attenuated the extent of liver inflammation and necrosis. Furthermore, Yinchenhao decoction did not result in hepatocyte degeneration and spleen weight loss that were observed in mice received long-term treatment with dexamethasone.
Conclusion
Yinchenhao decoction treatment protected liver against the ConA-induced chronic liver damage and improved liver function, which were associated with the modulation of gene expression related to immune/inflammatory response.

Key words: Concanavalin A, Liver injury, Chronic, Hepatitis, Chronic, Drug-induced, Cytokines, Immune, Liver protection, Yinchenhao decoction, Mice