Glomerular expression of endothelial nitric oxide synthase in deoxycorticosterone acetate-salt-treated rats

1. In the present study, we investigated the relationship between chronic v olume loading and glomerular endothelial nitric oxide synthase (eNOS) expre ssion. Immunohistochemical expression of eNOS in glomeruli was semiquantifi ed by graded scores of staining intensity. Each glomerulus was isolated by microdissection and mRNA expression was detected by reverse transcription-p olymerase chain reaction (RT-PCR) in desoxycorticosterone acetate (DOCA)-sa lt-treated rats. 2. Glomerular expansion and dilatation of tubules were the main histologica l findings and glomerular and vascular injury scores were significantly hig her in the DOCA-salt-treated group than in the control group. Endothelial N OS staining in glomeruli in DOCA-salt-treated animals was 81.4% lower than in control animals. Endothelial NOS mRNA was also detected at a very low ra te in the kidney of treated rats compared with control rats (22/80 vs 74/80 glomeruli, respectively). 3. These results suggest that eNOS protein and mRNA expression in glomeruli was reduced by DOCA-salt loading. Chronic volume loading may damage the gl omerulus and this may be mediated, at least in part, by disruption of eNOS.