Roles of nitric oxide and nitric oxide synthases in tissue damage of obstructed ureters in rats

Abstract

Objective To investigate the roles of nitric oxide (NO) and NO synthases [endothelial constitutive NO synthase (eNOS) and inducible NO synthase (iNOS)] in the pathogenesis of ureteric damage during the course of obstructive uropathy. Material and methods The expression of nitrotyrosine, eNOS and iNOS was studied in 54 Sprague–Dawley rats using immunohistochemistry with concurrent immunohistochemical staining. Results Hypertrophy and fibrotic changes of the smooth muscle of the obstructed ureters were noticed after ureteric ligation. The expression of iNOS, eNOS and nitrotyrosine in the smooth muscle layer was noticed from Days 7, 10 and 14 after ligation, respectively, increased until Day 21 post-ligation and then decreased. The expression of nitrotyrosine in the smooth muscle layer was significantly correlated with the expression of iNOS and eNOS (r=0.9698 and 0.9683, respectively; p<0.0001 for both). Conclusion NO and NO synthases may play important roles in tissue damage of the smooth muscle layer in obstructed ureters.

• Nitric oxide
• nitric oxide synthases
• nitrotyrosine
• obstructive uropathy
• ureter