OBJECTIVETo study the regulattory effect of Astragalus membranaceus on immune disturbance of the rats with IgA nephropathy.

METHODSRats IgA nephropathy (IgAN) model was duplicated by oral feeding of bovine serum albumin (BSA), subcutaneous injection of carbon tetrachloride (CCl4) and injection of lipopolysaccharide (LSP) into vena caudalis. The rats were divided into three groups randomly for the normal, IgAN model group and the group treated with Astragalus membranaceus (treatment group). The treatment group was given the Astragalus membranaceus granules via intragastric administratsion, the normal group and the IgAN model group were given the equal amount of aqua destillata by gastric perfusion. The rats were examined for albuminuria, hematuria and pathological changes of renal tissue and the distribution of TGF-beta and interleukin-5 in renal tissue was determined by immunohistochemistry and the IFN-gamma and IL-4 of cytokine of Th1 and Th2 types were detected in rats IgA nephropathy model by sandwich enzyme linked immunosorbent assay (ELISA).

RESULTS(1) The hematuria in rats with IgA nephropathy significantly increased compared with normal control group and Astragalus treatment group (P < 0.05). There was significant increase in albuminuria in rats with IgA nephropathy, compared with normal control group and astragalus treatment group (P < 0.01). (2) The pathological change of glomerular mesangium, renal tubules and renal interstitia became serious in rats IgA nephropathy model when compared with normal control group and astragalus treatment group. Immumofluorescence showed renal IgA density in rats IgA nephropathy model was significantly higher than that in the normal control group (P < 0.001) and astragalus treatment group (P < 0.001). (3) The result of immuno histochemistry showed that there was only weak expression of TGF-beta and interleukin 5 in normal renal tissue. The expression of TGF-beta and interleukin 5 in IgA nephropathy model was significantly stronger than those in normal control group (P < 0.05) and astragalus treatment group (P < 0.05). (4) The serum IL-4 levels were (33.74 +/- 7.52) pg/ml in rats IgA nephropathy model, significantly higher than that in normal control group (2.36 +/- 0.85) pg/ml and astragalus treatment group (3.24 +/- 1.13) pg/ml. The IFN-gamma level in serum of rats IgA nephropathy model was (18.79 +/- 3.80) pg/ml, which was significantly higher than that in normal control group (46.53 +/- 5.56) pg/ml and astragalus treatment group (41.28 +/- 2.95) pg/ml.

CONCLUSIONSThe astragalus could lower the level of hematuria and 24 hours-albuminuria of the IgAN model, and amelioratse the change of the renal pathology and reduce the deposit of IgA in glomerular mesangium. The possible mechanism of the effect is that astragalus could regulate the derangement of Th1, Th2, accordingly could improve the level of IL-4 and IFN-gamma in the serum and diminish the expression of cytokine Th2 TGF-beta1 and IL-5 of the renal tissue, and thereby could postpone the development of IgAN.