加压素对缺氧血管平滑肌细胞蛋白激酶C亚型表达的调节及其机制

目的 探讨精氨酸血管加压素(AVP)对缺氧血管平滑肌细胞(VSMC)中PKC-α、δ和ε亚型蛋白表达的调节作用及其可能机制.方法 取50只Wistar大鼠的血管进行原代VSMC培养,观察AVP对缺氧VSMC胞质和胞膜成分中PKC-α、δ和ε亚型蛋白表达的影响,同时检测缺氧VSMC中3种磷脂酶(PLC、PLD、PLA:)的活性变化及AVP和PKC亚型抑制剂对其的作用.结果 缺氧后VSMC胞膜成分中PKC.α和亚ε型的表达分别升高为正常组的1.5和2.0倍,而胞质成分中表达降低,AVP处理进一步升高胞膜PKC-α和ε亚型的表达(分别为正常组的2.4和2.6倍,P<0.05);而胞质和胞膜PKC-δ亚型有相似的变化趋势,但差异无统计学意义.同时,缺氧后PLC和PLD活性升高,AVP处理使PLC和PLD的活性进一步升高为正常组的1.6和2.1倍;PKC-α抑制剂Go 6976预处理可拮抗AVP诱导PLD活性升高的作用(PLD活性降低为AVP组的40.8%),而PKC-δ和ε抑制剂无明显作用;各组PLA2活性差异无统计学意义.结论 AVP可通过促进VSMC胞质中的PKC-α和ε亚型向胞膜转位而激活,进而调节休克后血管反应性;PLC和PLD可能参与了AVP介导的PKC激活过程.

Effect of vasopressin on the expression of protein kinase C isoforms of vascular smooth muscle cell after hypoxia and its mechanisms

Objective To observe the effect of arginine vasopressin (AVP) on the expression of PKC-ot,8 and e isoforms of vascular smooth muscle cell (VSMC) after hypoxia and its mechanisms. Methods With cultured VSMC from 50 Wistar ruts,the effect of AVP on the expression of PKC-α,δ and ε isoforms in the cytosol and particulate fractions of VSMC after hypoxia were observed. At the same time, the activity of phospholipase C (PLC) , phospholipase D (PLD) ,phospholipase A2 (PLA2) and the effects of AVP and PKC isoform inhibitors were also observed. Results The expression of particulate PKC-α and ε increased about 1.5 and 2.0 folds, respectively after 90-min hypoxia, with a concomitant decrease in cy-tosolic fractions. AVP treatment further increased expression of PKC-α and e in the particulate fractions to 2.4 and 2.6 folds(P < 0.05 ). While PKC-δ showed u similar changes in the particulate and cytosolie fractions during the process,but there were no statistical differences among the groups. At the same time, treatment with hypoxia for 1.5 h caused a significant increase in PLC and PLD activity, AVP further in-creased of PLC and PLD activity to 1.6 and 2.1 folds, PKC-α inhibitor Co 6976 antagonized AVP-induced increased in PLD activity,which reduced to 40.8% as compared to AVP alone group. The PLA2 activity had no significant changes among the groups. Conclusion AVP improved vascular reactivity following shock through translocating PKC-α and ε isoforms from a cytosol to a particulate and activation. And PLC and PLD may participate in the signal transdution pathway induced by AVP.