Effects of taurocholic acid on immunoregulation in mice

Context: Currently, there is a dramatically growing interest in Chinese traditional medicines, especially in the therapy of inflammatory diseases. Taurocholic acid (TCA), as a kind of natural bioactive substance of animal bile acid, has medicinal applications to treat a wide range of inflammatory diseases.

Objective: The study was designed to evaluate the effects of TCA on cytokine secretion, such as TNF-α and IL-1β and on the ratio of CD4(+)/CD8(+), which is beneficial for understanding the mechanism of TCA on immunoregulation preliminarily, and also will benefit our further research.

Materials and methods: The gene and protein expressions of TNF-α and IL-1β were measured by real time RT-PCR and ELISA in serum, spleen and lymphocytes respectively. The ratio of CD4(+)/CD8(+) in peripheral blood and lymphocytes was measured by flow cytometry.

Results: Our present study has shown that lipopolysaccharide (LPS) and cyclosporin A (CsA) could increase or decrease the gene and protein expressions of TNF-α and IL-1β respectively. TCA (0.25g/kg, 0.125g/kg) could recover the suppressed expressions of TNF-α and IL-1β and increase the ratio of CD4(+)/CD8(+). In vitro, TCA (15μg/mL) could inhibit the increased production of TNF-α and IL-1β; TCA (0.15μg/mL-15μg/mL) could inhibit the increased gene expressions of IL-1β and TNF-α. TCA (0.15μg/mL) could recover the suppressed expressions of TNF-α and IL-1β.

Conclusion: The function of immunoregulation of TCA may be accomplished through modulating the gene and protein expressions of TNF-α and IL-1β and elevating CD4(+)/CD8(+) T-cell ratio.