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Pharmacological characterization of perivascular adipose tissue (PVAT)-derived hydrogen sulphide (H2S) in gestational hypertension in rats


Hypertensive disorders of pregnancy are characterized by an increase in systemic blood pressure. Preeclampsia is considered the most severe of these disorders and is usually accompanied by proteinuria and other clinical symptoms after the 20th gestational week. Perivascular adipose tissue (PVAT) may participate in the control of vascular tone through the release of vasoactive substances, including hydrogen sulphide (H2S). H2S is endogenously synthesized by the enzyme cystathionine-gamma-lyase (CSE) and it has been shown that H2S levels are reduced in preeclampsia. Our objective is to evaluate the involvement of PVAT-derived H2S in vascular modulation during gestational hypertension. Pregnant rats will be divided into two groups: normal pregnancy (Norm-Preg) and hypertensive pregnancy (HTN-Preg). Gestational hypertension will be induced by "DOCA-Sal" model, which consists of deoxycorticosterone acetate (DOCA) administration with concomitant replacement of drinking water by saline. Systolic blood pressure will be measured by tail cuff plethysmography on days distributed during pregnancy, in a total of eight measurements. On the 20th gestational day, rats will be killed with isoflurane overdose. The thoracic aorta will be removed and used in vascular reactivity experiments to construction, where concentration-response curves to evaluate the effect of PVAT on vascular contractility to phenylephrine, the vasodilatory effect of H2S derived from PVAT, and to investigate the involvement of the dependent potassium channels of ATP (KATP) on the signaling of H2S derived from PVAT. The abdominal aorta and PVAT will be stored for molecular analyzes of Western Blot (to evaluate the protein expression of CSE), of real-time polymerase chain reaction (qPCR, to evaluate the gene expression of CSE by reverse transcriptase, RT) and immunohistochemistry in order to immuno-localize the CSE enzyme. The endogenous production of H2S will be evaluated in the aorta and PVAT through the technique of formation of lead sulphide. Angiogenesis will be evaluated with ELISA kits targeting angiogenic and anti-angiogenic factors. (AU)