Intrauterine Growth Restriction Does not Change the Regulation of Arterial Contractile Responses in Rats during Early Postnatal Period

Intrauterine growth restriction (IUGR) is one of the mostcommon pathologies of pregnancy. Due to this pathology, the functioningof many systems, including the cardiovascular, is impaired. In adult animals,who have suffered IUGR, the contribution of procontractile mechanismsof vascular tone regulation (e.g., Rho-kinase signaling pathway)increases, while that of anticontractile mechanisms (e.g., endothelialNO), on the contrary, decreases, which can lead to vasospasm andimpaired blood supply to the organs. Since NO and Rho-kinase playa pronounced vasomotor role in early postnatal ontogenesis, thiswork was aimed to assess the effect of IUGR on the contributionof these mechanisms to the regulation of arterial contractile responsesduring the early postnatal period in rats. IUGR was modeled by restrictingthe amount of food calories consumed by females (by 50%) since day11 of pregnancy until parturition. In rat offspring aged 11–12 days,we studied the responses of the isolated saphenous artery in isometricmode and evaluated the content of mRNA and proteins of interestin this artery. IUGR did not alter the offspring arterial reactivityto the α1-adrenergic receptor agonist methoxamine. The increasein vasocontractile responses to methoxamine in the presence of theendothelial nitric oxide synthase (eNOS) inhibitor L-NNA, as wellas the expression levels of eNOS (mRNA and protein) and arginase-2 (mRNA),did not change in the arteries of IUGR rat pups, whereas the arterialsensitivity to the exogenous NO donor DEA/NO was higher in IUGRvs. Control rat pups. Despite relatively low levels of RhoA andRho-kinase II proteins in the arterial tissue of IUGR rat pups,the decrease in contractile responses, elicited by the Rho-kinaseinhibitor Y27632, was equally pronounced in the arteries of rat pupsfrom both IUGR and Control groups. Thus, IUGR, caused by maternalnutritional restriction during pregnancy, causes no pronounced changesin the regulation of systemic vascular tone during the early postnatalperiod.