RESUMO
OBJECTIVE To study the effects of Phellodendron amurense polysaccharides （PAP） on improving gouty nephropathy （GN） in rats， and to investigate its mechanism primarily by interfering the p38 mitogen-activated protein kinase （p38 MAPK）/nuclear factor-κB（NF-κB）/tumor necrosis factor-α（TNF-α）. METHODS Sixty rats were randomly divided into normal group （water）， model group （water）， allopurinol group （positive control， 20 mg/kg）， PAP high-dose， medium-dose and low-dose groups （100， 50， 25 mg/kg， by raw material） after being stratified by body weight， with 10 rats in each group. Except for the normal group， the other groups were induced to construct GN model by giving 1 500 mg/kg potassium oxazinate and 100 mg/kg adenine intragastrically for 14 days. After modeling， the rats in each group were given relevant medicine/water intragastrically， once a day， for consecutive 28 days. After the last medication， the levels of biochemical parameters related to renal function [uric acid， creatinine （Cr）， blood urea nitrogen （BUN）， xanthine oxidase （XOD）] were detected in rats， and the histopathological changes in the rat kidney were observed. The protein expressions of monocyte chemoattractant protein-1（MCP-1），TNF-α and interleukin-6（IL-6） as well as the phosphorylation levels of p38 MAPK and NF-κB p65 protein were determined in renal tissue of rats. RESULTS Compared with the normal group， the model group suffered from the dilatation of renal tubules， structural damage to glomeruli， accompanied by inflammatory infiltration and fibrosis； the contents of uric acid， Cr， BUN and XOD， the protein expressions of MCP-1，TNF-α and IL-6 and the phosphorylation levels of p38 MAPK and NF-κB p65 protein were all increased significantly （P＜0.05 or P＜0.01）. Compared with the model group， the pathological symptoms of renal tissue in rats had been improved to varying degrees in different dose groups of PAP； the contents of uric acid， Cr， BUN and XOD， protein expressions of MCP-1， TNF-α and IL-6， the phosphorylation levels of p38 MAPK and NF-κB p65 protein in PAP high-dose and PAP medium-dose groups were all decreased significantly （P＜0.05 or P＜0.01）. CONCLUSIONS PAP exhibits an anti-GN effect， the mechanism of which may be associated with inhibiting the p38 MAPK/NF-κB/TNF-α signaling pathway.