Reciprocal Changes of Renal Neuronal Nitric Oxide Synthase-α and -β Associated With Renal Progression in a Neonatal 5/6 Nephrectomized Rat Model

Abstract

Nitric oxide (NO) deficiency contributes to chronic kidney disease progression. NO deficiency could occur for many reasons, one of which is decreased NO synthase (NOS) abundance and/or activity. Methods: In these experiments, we studied two groups of male Sprague Dawley rats given sham or surgical excision of both poles of the left kidney (at 2 days of age) followed by sham or surgical removal of the right kidney at 10 days. Rats were sacrificed at 9 weeks of age and the kidneys examined for abundance of neuronal NOS (nNOS)-α and -β, endothelial NOS, arginase II, argininosuccinate synthase and lysate, protein arginine methyltransferase 1, dimethylarginine dimethylamino-hydrolase 1 and 2, as well as renal pathology. Results: The 5/6 nephrectomy (NX) group showed renal dysfunction, severe rapidly progressing glomerulosclerosis, and hypertension. Renal cortical nNOSα abundance was significantly reduced, whereas nNOSβ abundance was increased in the 5/6 NX group versus sham. Renal endothelial NOS was unchanged. Next, renal protein arginine methyltransferase 1 abundance was higher, whereas dimethylarginine dimethylamino-hydrolase 2 expression was lower in the 5/6 NX group versus sham. Renal arginase II, argininosuccinate synthase, and argininosuccinate lysate abundances were significantly decreased in 5/6 NX rats than those in sham. Conclusion: The neonatal kidney is very susceptible to 5/6 NX-induced injury, and, as in adults, reciprocal changes in the nNOSα and nNOSβ in renal cortex occur during progression of chronic kidney disease and may contribute to the injury.

Keywords

• chronic kidney disease
• neuronal nitric oxide synthase
• remnant kidney