血小板衍生生长因子调节休克血管反应性的非MLC20磷酸化机制与HSP27和Caldesmon的关系

目的初步探讨非MLC20磷酸化途径在休克后血管低反应性中的调节作用及与钙调结合蛋白(Caldesmon)和热休克蛋白(HSP27)的关系。方法 SD大鼠48只,200~250g,雌雄不拘。取大鼠肠系膜血管环,观察缺氧后血管反应性和肌球蛋白轻链20(MLC20)磷酸化的变化,及对HSP27和Caldesmon活性的影响。采用反义寡核苷酸(AODN)抑制HSP27和Caldesmon后,观察血小板衍生生长因子(PDGF)调节血管反应性和MLC20磷酸化的变化。结果失血性休克后,血管反应性显著降低,不同浓度的PDGF(40、60、80、100ng/ml)可以增加休克后的血管反应性,且呈现剂量依赖性;然而不同浓度的PDGF(40、60、80、100ng/ml)对MLC20磷酸化的影响未呈剂量依赖性增加,但不同浓度的PDGF在调节Caldesmon和HSP27磷酸化时却呈现剂量依赖性,而且Caldesmon和HSP27的反义寡核苷酸可以抑制PDGF引起的血管反应性的增加,却不能抑制PDGF引起的MLC20磷酸化水平的增加。结论非MLC20磷酸化途径参与休克后血管反应性的调节,其机制与Caldesmon和HSP27相关。

Role of non-MLC20 pathway on PDGF regulation of vascular reactivity during shock and its relation with Caldesmon and HSP27

Objective To explore the mechanism of non-MLC20 phosphorylation dependent pathway on PDGF regulation of vascular reactivity following shock and its relation with Caldesmon and HSP 27.Methods For-ty-eight SD rats with a weight of 200-250 g were selected.The superior mesenteric arteries(SMAs)of the rats were analyzed .The vascular reactivity and the change of MLC 20 phosphorylation after hypoxemia and the effect on the activity of HSP27 and Caldesmon were observed .After the inhibition of Caldesmons and HSP 27 by antisense oli-godeoxynucleotide ( AODN) ,the regulation of PDGF on vascular reactivity and the change of MLC 20 phosphorylation were also observed . Results Vascular reactivity decreased significantly after shock . Different concentration of PDGF(40ng/ml,60ng/ml,80ng/ml,100ng/ml) increased the vascular reactivity after shock and showed obvious dose-dependent manner .Effects of PDGF at different concentration on MLC 20 phosphorylation did not increase with the increase of dosage .Different concentration of PDGF regulated Caldesmon and HSP 27 phosphorylation and in-creased with the increase of dosage .The AODN of Caldesmon and HSP27 could inhibit the increase of vascular re-activity induced by PDGF but could not inhibit the increase of MLC 20 phosphorylation induced by PDGF .Conclu-sion Non-MLC20 phosphorylation pathway takes part in the regulation of vascular reactivity after shock .Its mech-anism is related with Caldesmon and HSP 27.