ABSTRACT
The aim of this study was to investigate the molecular mechanisms underlying the protective effects of hypoxia-inducible factor (HIF) signaling pathway activation in cardiomyocytes under anoxia-reoxygenation (A/R) injury. In this study, rat neonatal cardiomyocytes were pretreated with anti-Hif3A/Hif-3α siRNA or HIF-prolyl hydroxylase inhibitor prior to A/R injury. Our results showed that both HIF3A silencing and HIF-prolyl hydroxylase inhibition effectively increased the cell viability during A/R, led to changes in mRNA expression of HIF1-target genes, and reduced the loss of mitochondrial membrane potential (Δψm). Furthermore, application of anti-Hif3a siRNA led to an increase in mRNA expression of Epo, Igf1, Slc2a1/Glut-1, and Slc2a4/Glut-4. Similar results were observed with HIF-prolyl hydroxylase inhibition, which additionally upregulated the mRNA expression of Epor, Tert, and Pdk1. Hif3a RNA-interference and application of HIF-prolyl hydroxylase inhibitor during A/R modelling led to an increase of Δψm on 11.5 and 11.9â¯mV respectively, compared to the control groups. Thus, Hif3a RNA interference and HIF-prolyl hydroxylase inhibition protect cardiomyocytes against A/R injury via the HIF signaling pathway.
Subject(s)
Cell Hypoxia/genetics , Dioxygenases/antagonists & inhibitors , Myocytes, Cardiac/drug effects , RNA Interference , Transcription Factors/genetics , Animals , Cell Survival/drug effects , Gene Expression/genetics , Gene Silencing/drug effects , Membrane Potential, Mitochondrial/drug effects , Myocytes, Cardiac/enzymology , RNA, Small Interfering/pharmacology , Rats , Rats, WistarABSTRACT
Pial arteries of different diameter were studied in intact rats and after 6-month modeling of chronic tobacco smoking in rats. Expression of tachykinin NK1 receptors in pial arteries was studied by biomicroscopy and immunohistochemical methods. Chronic tobacco smoking induced considerable reorganizations of the arterial bed. The intensity of changes depended on the diameter of vessels. In small pial vessels that directly participate in the blood supply to the brain, pronounced vasodilatation and enhanced expression of NK1 receptors in the endothelium mediating the effects of substance P were observed; the number of these vessels also increased. The intensity of the response to tobacco smoke components decreased with increasing vessel diameter.
Subject(s)
Cerebral Arteries/drug effects , Nicotiana/toxicity , Receptors, Tachykinin/genetics , Substance P/genetics , Vascular Remodeling/drug effects , Animals , Cerebral Arteries/metabolism , Cerebral Arteries/pathology , Gene Expression , Humans , Immunohistochemistry , Male , Models, Animal , Rats, Wistar , Receptors, Tachykinin/metabolism , Substance P/biosynthesis , Tobacco Smoking/physiopathology , Vasodilation/drug effectsABSTRACT
We studied vasomotor responses of aortic endothelium in a rat model of chronic smoking. It was found that long-term exposure to tobacco smoke (inhalation) impaired vasomotor function of the aortic endothelium leading to insufficient vasodilator activity and enhanced vasoconstriction. After the cessation of inhalations, vasomotor disturbances were not only preserved, but also exacerbated because of increased pathological endothelium-independent vasoconstriction.
