EXPRESSION OF INDUCIBLE NITRIC-OXIDE SYNTHASE AND APOPTOSIS IN HUMAN LUPUS NEPHRITIS

To understand the expression of inducible nitric oxide synthase (iNOS) and its possible association with apoptosis in human lupus nephritis, 48 renal tissue samples from patients with lupus nephritis were inves tigated immunohistochemically and by the terminal-deoxynucleotidyl-tra nsferase-mediated dUTP nick end labeling method for the detection of i NOS and apoptosis, respectively. Modulation of apoptosis by p53 and Bc l-2 was also evaluated. This study showed immunohistochemical evidence of iNOS expression, predominantly in the glomerular and tubulointerst itial cells of class-IV lupus nephritis. The frequency of iNOS+ glomer uli was significantly correlated with that of apoptosis+ glomeruli, an d the frequency of the latter was also significantly correlated with t hat of the glomeruli showing p53 overexpression. Bcl-2 was predominant ly expressed in the cellular and fibrocellular crescents. This study s uggests that induction of iNOS, and thus nitric oxide production, play s a role in the occurrence of apoptosis in the glomeruli of lupus neph ritis; and the occurrence of apoptosis might in part be modulated by p 53 and Bcl-2-related pathways. The expression of Bcl-2 in predominantl y cellular and fibrocellular crescents suggests that Bcl-2 may partici pate in persistent proliferation of the crescentic cells.