失血性休克大鼠PKCα mRNA表达变化规律及对血管低反应性的调节作用

Changes of PKCα mRNA expression and its role in vascular hyporeactivity during hemorrhagic shock in rats

目的观察PKCα在大鼠失血性休克血管平滑肌中mRNA表达变化规律，及其对失血性休克血管反应性和钙敏感性的调控作用。方法采用PCR技术测定大鼠肠系膜上动脉不同休克时间点（休克即时、30min、1h、2h、4h）的PKCamRNA表达；用离体血管环张力测定技术观察不同休克时间点的肠系膜上动脉一级分支的血管环反应性和钙敏感性变化，以及PKCα激动剂和抑制剂对休克2h血管反应性、钙敏感性的影响。结果①失血性休克后大鼠血管反应性和钙敏感性早期增高、晚期降低，PKCαmRNA表达逐渐增高，于1h达到峰值（P〈0．01），4h时仍处于较高水平（P〈0．01）。②PKCα激动剂和抑制剂可分别增高和降低休克2h大鼠的血管反应性和钙敏感性。结论PKCα在失血性休克血管反应性和钙敏感性调控中起重要作用，可能是休克血管功能的重要保护性分子。

Objective To observe the changes of PKCα mRNA expression of superior mesenteric artery（SMA） tissue and its role in vascular hyporeactivity following hemorrhagic shock（HS） in rats. Methods The SMA from hemorrhagic shock rats of different time after shock（ immediately, 30 min, 1 h, 2 h, 4 h） were adopted to determine the mRNA expression of PKCα using RT - PCR technique, and the first class arborization of SMA were adopted to determine the vascular reactivity and calcium sensitivity via observing the contraction initiated by norepinephrine（NE） and Ca^2＋ with isolated organ perfusion system. The agonist and inhibitor of PKCot were used to observe the regulation of PKCα on vascular hyporeactivity following hemorrhagic shock. Results ①Vascular reactivity and calcium sensitivity of the first class arborization of SMA were increased at the early stage of HS, then decreased gradually. PKCα mRNA showed a time - dependent increase following HS, peaked at 1 h（ P 〈0. 01 ） and maintained at a high level at 4 h（ P 〈 0.01 ）. It was low level - expressed in normal control group. ②The agonist of PKCα thymelea toxin increased the vascular reactivity and calcium sensitivity of SMA at 2 h shock, and Go - 6976,its inhibitor, decreased the vascular reactivity and calcium sensitivity. Conclusion PKCα plays an important role in the regulation of vascular reactivity and calcium sensitization following HS, it may be an important protective molecule to vascular function after shock.