Anti-hypertensive And Vasodilatory Effects Of Qingda Granules By Suppression Of The PI3K/AKT Pathway

Objective:The purpose of this study is to investigate the pharmacological effect of Qingda Granules?QDG?optimized by Qingxuan Jiangya Decoction?QXJYD?on vascular tension and the regulation of ion channel and PI3K/AKT signaling pathway.The present study will provide experimental basis for clinical antihypertensive treatment of QDG.Methods:1.The isolated rat thoracic aortic rings were in the resting state or pre-contracted with norepinephrine?NE?or potassium chloride?KCl?,followed by different concentrations of QXJYD and QDG treatment,respectively.And then the vasorelaxation effect of QXJYD and QDG on the rings was observed.2.The blood pressures of 12 male Spontaneously Hypertensive rats?SHR?and 6 Wistar Kyoto?WKY?rats were measured by tail-cuff plethysmograph method using CODA?non-invasive blood pressure system.The vascular elasticity of the rat thoracic aortic rings were detected after QDG treatment for 8 weeks.3.The vasorelaxation effects of QDG on vasoconstriction of aortic rings induced by NE,KCl and angiotensin??Ang??was observed by using the isolated rat thoracic aortic rings to establish isolated vascular circulation perfusion model.To estimate the role of the endothelium in QDG-mediated vasorelaxation in the rat thoracic aortic rings,the aortic rings with and without the endothelium precontracted with NE?1?M?were incubated with QDG.The relationship between QDG-induced vasorelaxation and K⁺/Ca²⁺channel was investigated by the pretreatment of aortic rings with or without K⁺/Ca²⁺channel inhibitor before constriction with NE.4.In Ca²⁺-free Kreb's solution,the vasorelaxation of QDG on the contraction of vascular rings induced by different concentrations of CaCl₂ after KCl and NE stimulation was investigated.The effect of QDG on intracellular and extracellular calcium of A7r5cell-pretreated with KClorNE was inversigated by the laser scanning confocal microscope.5.Western-blot were used to determine the expression of PI3K?AKT and p-AKT on rat thoracic aortic rings after QDG treatment.Result:1.QDG and QXJYD treatment significantly induced the vasorelaxation of thoracic aortic rings precontracted with KCl and NE.2.After treatment with QDG for 8 weeks,the elevation of SBP,DBP,MAP in SHRs was significantly attenuated and the vascular elasticity was profoundly increased in SHRs.3.QDG treatment increased the relaxation of isolated thoracic aortic rings precontra cted with NE,KCl and Ang?in an endothelium-independent manner,which was attenuated by treatment with verapamil,but not by treatment with TEA,4-AP,Gli,or BaCl₂.4.QDG pretreatment attenuated the CaCl₂-induced constriction of isolated thoracic aortic rings in K⁺-or NE-containing Ca²⁺-free solutions.In addition,QDG pretreatment significantly inhibited the influx of Ca²⁺in A7r5 cells induced by a K⁺-or NE-containing Ca²⁺solution.5.QDG treatment decreased the levels of PI3K and p-AKT,but had no effect on levels of total AKT protein in isolated thoracic aortic rings.Conclusions:QDG and QXJYD treatment significantly induced the vasorelaxation of thoracic aortic rings.QDG treatment attenuated elevated blood pressure and protected the vascular elasticity.By inhibiting the influx of Ca²⁺and the activation of PI3K/AKT singal pathway might be the underlying mechanisms of QDG treatment on anti-hypertension and vasorelaxation of QDG on thoracic aortic rings.