Protective effect of modified Huangqi Chifeng decoction(加味黄芪赤风汤)on immunoglobulin A nephropathy through toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-kappa B signaling pathway

OBJECTIVE:To examine the nephroprotective mechanism of modified Huangqi Chifeng decoction(加味黄芪赤风汤,MHCD)in immunoglobulin A nephropathy(IgAN)rats.METHODS:To establish the IgAN rat model,the bovine serum albumin,lipopolysaccharide,and carbon tetrachloride 4 method was employed.The rats were then randomly assigned to the control,model,telmisartan,and high-,medium-,and low-dose MHCD groups,and were administered the respective treatments via intragastric administration for 8 weeks.The levels of 24-h urinary protein,serum creatinine(CRE),and blood urea nitrogen(BUN)were measured in each group.Pathological alterations were detected.IgA deposition was visualized through the use of immunofluorescence staining.The ultrastructure of the kidney was observed using a transmission electron microscope.The expression levels of interleukin-6(IL-6),monocyte chemoattractant protein-1(MCP-1),and transforming growth factor-β1(TGF-β1)were examined by immunohistochemistry and quantitative polymerase chain reaction.Levels of toll-like receptor 4(TLR4),myeloid differentiation factor 88(MyD88),and nuclear factor-kappa B(NF-κB)P65,were examined by immunohistochemistry,Western blotting,and quantitative polymerase chain reaction.RESULTS:The 24-h urine protein level in each group increased significantly at week 6,and worsen from then on.But this process can be reversed by treatments of telmisartan,and high-,medium-,and low-dose of MHCD,and these treatments did not affect renal function.Telmisartan,and high-,and medium-dose of MHCD reduced IgA deposition.Renal histopathology demonstrated the protective effect of high-,medium-,and low-dose of MHCD against kidney injury.The expression levels of MCP-1,IL-6,and TGF-β1 in kidney tissues were downregulated by low,medium and high doses of MHCD treatment.Additionally,treatment of low,medium and high doses of MHCD decreased the protein and mRNA levels of TLR4,MyD88,and NF-κB.CONCLUSIONS:MHCD exerted nephroprotective effects on IgAN rats,and MHCD regulated the expressions of key targets in TLR4/MyD88/NF-κB signaling pathway,thereby alleviating renal inflammation by inhibiting MCP-1,IL-6 expressions,and ameliorating renal fibrosis by inhibiting TGF-β1 expression.