Effect Of GPER On The Relaxation And Contraction Function Of Renal Interlobular Artery After RIRI In Rats And Its Mechanism

Objective: To investigate the effect of G protein-coupled estrogen receptor(GPER)on the relaxation and contraction function of renal interlobular artery after Ischemia Reperfusion Injure(IRI)in SD rats and its mechanism.Methods: In this study,normal female Sprague-Dawley rats were used to establish an ovariectomy(OVX)model.Two weeks later,ovariectomized female rats were divided into OVX group,OVX+IR group,OVX+IR+G1(GPER agonist)group.OVX+IR+G1+G15(GPER blocker)group,OVX+IR+G1+L-NAME(nitric oxide synthase inhibitor)group.The right kidney was excised and the left kidney pedicle was clamped with a non-invasive arterial clip to prepare a rat kidney ischemia-reperfusion injury model.Blood samples were taken from the abdominal aorta to determine serum creatinine(SCr)and urea nitrogen(BUN)levels,and renal function was measured.Renal tissue sections were subjected to terminal deoxynucleotidyl transferase-mediated deoxynucleotide uridine nick end labeling(TUNEL staining)and hematoxylin-eosin(HE)and Paller-style scoring to evaluate renal tissue and The degree of damage to the interlobular artery.The inter-renal artery was isolated in vitro,and the contraction and relaxation activities of each group of inter-coronary arteries were detected by in vitro microvascular pressure diameter measurement technique.Immunofluorescence technique was used to observe the localization and expression of GPER and e NOS in the inter-renal artery.The expression levels of GPER and e NOS protein in each group of inter-coronary arteries were detected by Western Blot.The content of nitric oxide(NO)in the serum of each group was determined by nitrate reductase method.Results:(1)TUNEL staining showed a significant increase in renal tubular epithelial cell apoptosis after renal ischemia-reperfusion(P<0.01);(2)significant levels of serum creatinine(SCr)and blood urea nitrogen(BUN)after renal ischemia-reperfusion injury Increased(P<0.01),glomerular shrinkage deformation,renal tubular epithelial cell structure was destroyed,Paler-type score showed increased renal tissue damage(P<0.01).At the same time,the structure of the interlobular artery was significantly damaged.Intervention of G1 can significantly reduce serum BUN and SCr levels after ischemia-reperfusion injury(P<0.01),and can maintain the morphology and structure of renal tissue and inter-renal artery endothelial cells intact,G15 and L-NAME partially reverse G1 The effect(P<0.01);(3)After renal ischemia-reperfusion injury,the renal artery arterial contraction rate and vasoconstriction rate were significantly decreased(P<0.01).After G1 intervention,the contraction rate and contraction rate of blood vessels were increased(P<0.01),and G15 and L-NAME partially reversed this effect after intervention(P<0.01).(4)Immunofluorescence technique showed that GPER was expressed in renal intervascular arterial smooth muscle cells and endothelial cells,and the fluorescence intensity of GPER increased after ischemia-reperfusion,and the fluorescence intensity of e NOS decreased(P<0.01).(5)Western blot results showed that GPER protein expression increased after ischemia-reperfusion injury(P<0.01),and e NOS protein expression decreased significantly(P<0.01).After G1 intervention,the expression of GPER protein did not change significantly,while the content of e NOS increased significantly(P<0.01).(6)After ischemia-reperfusion,the content of nitric oxide in serum decreased,and the level of G1 increased after intervention(P<0.01).G15 and L-NAME reversed the effect of G1 to different degrees(P<0.01).Conclusion: GPER is expressed on the inter-renal artery and the expression of GPER is increased after ischemia-reperfusion injury.Activation of GPER can significantly improve renal function after renal ischemia-reperfusion,reduce renal tissue damage,improve structural changes of renal interlobular artery endothelial cells,and enhance the relaxation and contraction of renal interlobular artery.Simultaneous activation of GPER can increase the expression of e NOS on the inter-renal artery and increase the content of nitric oxide in serum.The results showed that activation of GPER can improve the function of renal interlobular artery by increasing NO content,thereby preventing renal ischemia-reperfusion injury.