缝隙连接及其连接蛋白对血管加压素诱导的失血性休克大鼠血管收缩的作用研究

Roles of Gap Junctions and Its Connexins in Vasopressin–induced Vasoconstriction After Hemorrhagic Shock

目的观察缝隙连接(gap junction,GJ)及其组成亚单位连接蛋白(connexin,Cx)在血管加压素(arginine vasopressin,AVP)诱导失血性休克大鼠血管收缩中的作用。方法采用失血性休克大鼠模型和缺氧培养血管平滑肌细胞(vascular smooth muscle cells,VSMC),观察GJ阻断剂甘珀酸和辛醇以及各Cx亚型反义寡核苷酸(antisense oligodeoxynucleotide,AODN)对AVP诱导的血管收缩反应的影响,随后进一步观察参与AVP作用的Cx37和Cx43对AVP调节休克血管钙敏感性和缺氧VSMC内钙离子浓度的影响。结果 GJ阻断剂甘珀酸和辛醇明显抑制了AVP诱导的休克血管的收缩反应。在所有血管中表达的连接蛋白中,Cx37AODN和Cx43AODN明显抑制了AVP的血管收缩作用。进一步结果显示,不是Cx37AODN,而是Cx43AODN可拮抗AVP升高休克血管钙敏感性的作用。此外,AVP处理和干扰Cx37及Cx43对缺氧VSMC内钙离子浓度无明显影响。结论 GJ在休克后AVP介导的血管收缩调节中有重要作用,Cx37和Cx43参与了这一过程,其中Cx43可能通过影响AVP介导的血管钙敏感性调节途径来发挥作用,而Cx37可能通过其他机制参与AVP的血管调节作用。

OBJECTIVE To investigate the role of gap junctions（GJ） and the GJ channel protein connexins（Cxs） in arginine vasopressin（AVP）-induced vasoconstriction after hemorrhagic shock. METHODS With a rat model of hemorrhagicshock and hypoxia-treated vascular smooth muscle cells（VSMCs）, the effects of GJ blockers carbenoxolone（CBX） and octanol, and the antisense oligodeoxynucleotides（AODNs） of Cxs on the AVP-mediated contractile response of superior mesenteric arteries（SMAs） after shock, and the effects of Cx37 and Cx43 on AVP-regulating the calcium sensitivity of SMAs after shock and intracellular calcium concentration in VSMCs after hypoxia were observed. RESULTS GJ blockers CBX and octanol significantly decreased the contractile response of SMAs to AVP after shock. Among all connexins that expressed in vessels, the AODNs of Cx37 and Cx43 significantly inhibited the vascular contractile effect of AVP after shock. Furthermore, Cx43 AODN, but not Cx37 AODN, significantly antagonized the AVP-induced increase of the calcium sensitivity of SMAs after shock. In addition, AVP treated or silencing of Cx37 and Cx43 had no significant influences on the intracellular calcium concentration in hypoxic VSMCs. CONCLUSION GJ plays an important role in AVP-mediated vascular contractile effect after hemorrhagic shock. Cx43 and Cx37 are the main isoforms of connexin involved. Cx43 plays effect mainly through AVP-mediated calcium sensitization pathway, while Cx37 may be through other mechanisms.