OBJECTIVETo investigate the effects of astragalus on tubulointerstitial lesions in rats with IgA nephropathy (IgAN) and to explore the possible mechanism.

METHODSTwenty-eight Sprague-Dawley rats were randomly assigned to three groups. The rat model of IgA nephropathy was induced by intragastric administration of bovine serum albumin and injections of LPS and CC14. Six weeks later, the rats with IgAN were randomly treated with oral astragalus (3 g/kg/d, for 6 weeks) or normal saline. Normal control rats which were not subjected to IgAN were treated with normal saline. The number of urinary erythrocytes and urinary protein and B-D-N-Acetyl glucosaminidase (NAG) contents were determined by Pan-automatic biochemistry analyzing meter. Expression of monocyte chemotactic protein-1 (MCP-1) and nuclear factor-kappa B (NF-kappaB) in tubulointerstitial tissues were analyzed by immunohistochemistry. A semiquantitative score was used to evaluate the degree of renal pathologic lesions.

RESULTSThe number of urinary erythrocytes (74.02+/-16.58 / microL vs 383.23+/-4.94 /microL) and urinary protein (13.88+/-4.94 vs 59.82+/-14.73 mg/L) and NAG contents (2.84+/-0.31 vs 5.24+/-0.80 U/L) in the astragalus-treated IgAN rats decreased remarkably compared with those in the IgAN rats without astragalus treatment (P<0.01). Expression of the NF-kappaB and MCP-1 in the renal tissues in the IgAN rats without astragalus treatment was significantly higher than that in the astragalus-treated IgAN rats and normal control rats (P<0.01). There were significant differences in the scores of renal pathologic lesions between the IgAN rats with or without astragalus treatment (6.03+/-0.46 vs 10.57+/-1.23; P<0.01).

CONCLUSIONSAstragalus can decrease the number of urinary erythrocytes and urinary protein and NAG contents, and relieves tubulointerstitial lesions, possibly through the down-regulation of NF-kappaB and MCP-1 expression in rats with IgAN.