Endothelin Induced Vascular Smooth Muscle Contraction Weakened And Endothelin Receptor

Part ⅠThe correlation between late pregnancy and contraction weakness of vascular smooth muscle cells in aorta of ratObjective:to investigate the correlation between late pregnancy and contraction weakness of vascular smooth muscle cells in aorta.Methods:vascular smooth muscle cells were isolated from aorta of late pregnancy, virgin and middle pregnancy.then stimulated them with adrenergic receptor agonist phenylephrine(PHE),membrane depolarization thing potassium chlorid(KCl) and endothelin(ET) respectively to observe and record the contraction of these VSMCs.Results:VSMC s were isolated successfully from all tree groups.Stimulation from PHE,KCl and ET all could cause VSMCs contract.Compare to the virgin and middle pregnancy groups, contraction intensity of VSMCs from late pregnancy was lower in all three experiments.conclusion:Compare to the virgin and middle pregnancy groups, contraction intensity of VSMC induced by ET was weaker in the rats of late pregnancy. Part ⅡThe correlation between endothelin receptor and contraction weakness of VSMC in aorta of late pregnancy ratObjective:to investigate the contraction change of VSMC in late pregnancy rat which induced by ET after ETAR and ETBR were blocked respectively.Methodes:VSMCs were isolated from aorta of late pregnancy, virgin and middle pregnancy,pretreated them with ETAR and ETBR blockers respectively or simultaneously and then stimulated with ET-1, observed the difference of VSMC contraction between three groups.Results:pretreated the VSMCs with ETAR and ETBR blockers respectively and then stimulated with ET-1, VSMC contraction reduced in varying degree in all three groups. Compare to the virgin and middle pregnancy groups, contraction intensity of VSMC from late pregnancy was lower in both groups. While we blocked ETAR and ETBR simultaneously then stimulated with ET-1,three groups of rat aorta VSMCs were no significant contraction.Conclusion:Combined with either ETAR or ETBR seperately,ET could induce VSMC contract.Compare to virgin and middle pregnancy groups,the VSMC contraction in late pregnant rat was relatively weaker in both groups. Part IIIETAR and ETBR distribution changes of VSMC and vascular wall in rat aorta during late pregnancyObjective:To explore ETAR and ETBR distribution changes of vascular wall and VSMC in rat aorta during late pregnancy.Methods:Observe morpholigical changs of aorta and distribution diversification of ETAR and ETBR in the aorta and VSMC during late pregnancy involving H&E staining,immunohistocheniical staining and immunlfluorecence staining.Results:H&E staining of aorta showd a typical cytoplasmic and extracellular matrix components red and nuclei blue change. Compared to the virgin and middle pregnancy groups,there were not significant change in late pregnancy group.But the ratio of endometrial,medial and adventitia to vascular wall was changed.The medial/total thickness increased and adventitia/total thickness decreased in late pregnancy group.With ETAR and ETBR as the first antibody respectively, immunohistochemical staining to aorte slides of all three groups showed brown. It mainly concentrated in the medial with ETAR as the first antibody.Compared to the virgin and middle pregnancy groups,the staining of aorta slides in late pregnant rat was lighter. While we stained with ETBR as the first antibody, the aorta slides showed brown in both endometrial and medial,but mainly in medial. Compared to the virgin and middle pregnancy groups, staining of aorta slides in late pregnancy showed deeper in endometrial while lighter in medial.Immunlfluorecence staining with ETAR and ETBR as the first antibody respectively,we observed VSMCs were stained in all three groups. Compared to the virgin and middle pregnancy groups, VSMC staining in late pregnancy showed weaker in either ETAR or ETBR groups. Conclusion:Compared to the virgin and middle pregnancy rats, the number and distribution of ETAR and ETBR have both undergone a change during late pregnancy.