Intrauterine growth restriction does not lead to pronounced changes in the regulation of arterial contractile responses in rats in the early postnatal period

Intrauterine growth retardation (IUGR) is one of the most common pathologies of pregnancy. As a result of this pathology, the functioning of many systems, including the cardiovascular system, is disrupted. In adult animals who have suffered IUGR, the contribution of procontractile mechanisms regulating vascular tone (for example, the Rho-kinase signaling pathway) increases, and the contribution of anticontractile mechanisms (for example, endothelial NO), on the contrary, decreases, which can lead to vasospasm and impaired blood supply to organs. Since NO and Rho-kinase have a pronounced vasomotor role in early postnatal ontogenesis, the purpose of this work was to assess the influence of IUGR on the contribution of these mechanisms to the regulation of arterial contractile responses in early postnatal ontogenesis. IUGR was modeled by limiting the amount of food consumed by females (by 50%) from the 11th day of pregnancy until birth. In offspring aged 11 - 12 days, the reactions of the isolated saphenous artery were studied in isometric mode, and the content of mRNA and proteins of interest in this artery was also assessed. IUGR did not lead to a change in the reactivity of the arteries of the offspring to the α1-adrenergic receptor agonist methoxamine. The increase in contractile responses to methoxamine in the presence of the NO-synthase inhibitor L-NNA, as well as the expression levels of eNOS (mRNA and protein) and arginase-2 (mRNA) were not changed in the arteries of IUGR rats, while the sensitivity of the arteries to the exogenous NO donor DEA /NO was higher in IUGR compared to control rat pups. Despite the relatively low content of RhoA and Rho-kinase II proteins in the arterial tissue of rat pups from the IUGR group, the decrease in contractile responses under the influence of the Rho-kinase inhibitor Y27632 was equally pronounced in the arteries of rat pups from two experimental groups. Thus, IUGR, caused by maternal nutritional restriction during pregnancy, does not lead to pronounced changes in the regulation of systemic vascular tone in the early postnatal period.