Italian Journal of Anatomy and Embryology - contenuto non piu disponibile

Moderate hyperoxia alters alveolar and vascular lung morphogenesis. Nitric oxide (NO) and matrix metalloproteinases (MMP) have a crucial role in the homeostasis of the matrix and bronchoalveolar structure and may be regulated abnormally by exposure to hyperoxia. Disruption of vascular endothelial growth factor (VEGF)-NO signaling impairs vascular growth and contributes to hyperoxia-induced vascular disease in bronchopulmonary dysplasia (BPD). We hypothesize that L-citrulline, by raising the serum levels of L-arginine and enhancing endogenous NO synthesis, might attenuate hyperoxia-induced lung injury in an experimental model of BPD. Neonatal rats (1 day old) were exposed to 60% oxygen or room air for 14 days and administered L-citrulline or a vehicle (sham). Lung morphometry were performed; Serum was tested for arginine level; Matrix metalloproteinases2 (MMP2) gene expression, VEGF gene and protein expression and endothelial NO synthase (eNOS) protein expression were compared. Mean linear intercept was higher in the hyperoxia and sham groups when compared with the room air (RA) and L-citr+hyperoxia treated group (p