Objective: To investigate the effect of the serum of rats fed with Shenkang pill in regulating monocyte chemoattractant protein 1 (MCP-1) expression induced by advanced oxidation protein products (AOPP) in mouse podocyte clone 5 (MPC5) and explore the underlying mechanism.
Methods: MPC5 cultured in vitro were incubated for different time lengths in the presence of different concentrations of serum of rats medicated with Shenkang pill, and the cell proliferation was assessed using MTT assay. In MPC5 treated with AOPP prior to exposure to the rat serum, the changes in the protein expressions of p38MAPK and IκBα were examined with Western blotting, NF-κB p65 nuclear translocation was analyzed with immunofluorescence assay, and MCP-1 expression in the supernatant was determined using ELISA kits.
Results: The medicated rat serum time- and concentration-dependently promoted the proliferation of MPC5, with the optimal serum concentration of 5% and incubation time of 24 h. AOPP significantly increased MCP-1 expression in the cell supernatant in a time-and concentration-dependent manner; pretreatment with SB203580 (a p38 inhibitor) or parthenolide (a NF-κB inhibitor) significantly decreased MCP-1 expression, and treatment with the medicated serum significantly decreased AOPP-induced MCP-1 expression. AOPP concentration-dependently increased the protein expression of P-p38 but decreased that of IκBα. Both the medicated serum and SB203580 increased IκBα protein in AOPP-induced cells, but the effect was more obvious with the medicated serum. The medicated serum also decreased NF-κB p65 nuclear translocation in AOPP-induced MPC5.
Conclusion: Shenkang pill-medicated serum can decrease AOPP-induced expression of MPC-1 in MPC5 by regulating p38MAPK/NF-κB to mediate its anti-inflammatory effect. This finding provides a new theoretical basis for the application of Shenkang pill to treat diabetic nephropathy.