Immunoregulatory effects of sinomenine on the T-bet/GATA-3 ratio and Th1/Th2 cytokine balance in the treatment of mesangial proliferative nephritis

Sinomenine has been used to treat autoimmune diseases for centuries. However, the mechanism underlying its therapeutic effects remains unknown. Increasing recognition of the importance of the Th1/Th2 imbalance in nephritis has raised the questions of whether there is a Th1/Th2 imbalance in patients with mesangial proliferative nephritis (MsPGN) and whether sinomenine can modulate the Th1/Th2 imbalance. In this study, 25 MsPGN patients were treated with sinomenine and followed for 3 months. The expression of T-bet and GATA-3 mRNA in peripheral blood mononuclear cells (PBMCs) and the serum levels of interferon-gamma (IFN-gamma), interleukin (IL)-4, and IL-10 were studied at month 0, month 1, and month 3. The intra-renal expression of T-bet and GATA-3 was studied via immunohistochemistry. Results reveal that PBMCs from MsPGN patients expressed high levels of T-bet mRNA and low levels of GATA-3 mRNA, and the T-bet/GATA-3 ratio in MsPGN patients was significantly higher than that in healthy donors. Meanwhile, MsPGN patients were found to have simultaneously elevated IFN-gamma values and decreased IL-10 values. Immunohistochemistry revealed increased T-bet and decreased GATA-3 expression in renal tissues from MsPGN patients. Moreover, sinomenine was found to cause a decrease in T-bet mRNA expression, resulting in a drop in the T-bet/GATA-3 ratio. Sinomenine was also found to elicit a decrease in the serum levels of IFN-gamma. These results suggest that a shift toward the Th1 pathway of Th cell activation occurs in MsPGN patients, and that sinomenine has the potential to counter this shift in the Th1/Th2 balance and thereby produce therapeutic effects. (C) 2009 Published by Elsevier B.V.