Nitric oxide (NO) donor 3-morpholinosydnonimine antagonizes cyclosporin A-induced contraction in two in vitro glomerular models.

Cyclosporin A induces in vivo a severe nephrotoxicity characterized by a large decrease in renal hemodynamics. The aim of this study is to establish the ability of the known NO donor 3-morpholinosydnonimine (SIN-1) to prevent the cyclosporin A-induced contraction by using rat isolated glomeruli and cultured glomerular mesangial cells. Isolated rat glomeruli are obtained from the renal superficial cortex by a sieving method. Mesangial cells are cultured in RPMI 1640 with 15% fetal calf serum. The planar surface area (PSA) of either isolated glomeruli or mesangial cells is assessed using an image analyzer. Each glomerulus or mesangial cell serves as its own control through calculation of the area before any drug incubation and after incubation for 10, 20 and 30 min either in control solution or in control solution with cyclosporin A alone or cyclosporin A and SIN-1. Cyclosporin A (10(-6) mol/L) induces an important time-dependent contraction of either glomerulus or mesangial cell. When pretreated with different concentrations of SIN-1 (10(-4) to 10(-9) mol/L), only a slight size decrease is noted. In conclusion, a direct constrictive effect of cyclosporin A in isolated glomeruli and mesangial cells can be prevented by the NO donor SIN-1, suggesting an important involvement of the nitric oxide pathway in the cyclosporin A-induced nephrotoxicity.