The Role Of Mast Cell Infiltration In Renal Interstitial Fibrosis In An Animal Model With Protein-overload Nephropathy

Objective: To investigate the correlation of number of mast cells in kidney with renal interstitial fibrosis , expression of TGF-β1 and SCF in an animal model with protein-overload nephropathy.Methods: Uninephrectomized SD rats were randomly divided into the model group (intraperitoneal injections of bovine serum albumin) and the control group (intraperitoneal injections of equal volume of saline). Each group consisted of 30 rats. Twenty-four-hour urine samples were measured weekly. 10 rats from the model and the control group each were sacrificed at the 3rd, 7th and 11th week after injection. The intensity of mast cell infiltration was examined by toluidine blue (TB) staining and immunohistochemistry using a monoclonal anti-MC chymase antibody. The expression of TGF-β1 and SCF was measured by immunohistochemistry, using a monoclonal mouse anti-rat TGF-β1 antibody and a polyclonal rabbit anti-rat SCF antibody. Clinical data of these SD rats at the time of sacrifice were collected.Results:1 . In BSA-injected rats, obvious proteinuria and hypoproteinemia were observed. The renal function was normal. There was pronounced renal interstitial fibrosis and inflammatory cell infiltration.2．Renal injury was accompanied by mast cell infiltration, in close proximity to areas of interstitial fibrosis. With aggravation of interstitial lesions degree, the number of chymase-postitive mast cells and TB-positive mast cells had increased (P < 0．05) .3．Immunostainable SCF and TGF-β1 was detected in the tubulointerstitium (tubular cells, peritubular capillaries, and the renal interstitium) and a few intercapillary cells and glomerular parietal epithelial cell. Mast cells were obviously correlated with interstitial fibrosis and the expression of TGF-β1 and SCF(all P < 0．01) .Conclusion:1．Increased infiltration of mast cells correlates with the degree of interstitial fibrosis in protein-overload nephropathy.2．Mast cells may come to kidney by chemotactic actions of SCF and contribute to the development of renal fibrosis induced by proteinuria through secreting chymase and increasing the expression of TGF-β1．...