蛋白激酶C对低氧猪肺动脉平滑肌细胞结构型一氧化氮合酶mRNA表达作用的探讨

目的 探讨蛋白激酶C（PKC）信号传导通道对低氧猪肺动脉平滑肌细胞（PASMC）结构型一氧化氮合酶（cNOS)mRNA表达的影响。方法 采用逆转录－聚合酶链（RT－PCR）方法测定了低氧条件下猪PASMC中PKC－α和cNOS mRNA表达情况,并观察了PKC激活剂和抑制剂对cNOS mRNA表达的影响。结果 低氧48、72h PKC-α mRNA的表达明显升高（P＜0．01）,cNOS mRNA的表达明显降低（P＜0．01）,cNOS mRNA的表达与PKC－α mRNA的表达呈显著负相关（P＜0．001）。PKC激活剂豆寇酸佛波醇乙酯（PMA）可使cNOS mRNA在低氧PASMC中的表达进一步降低,而KC抑制剂RO 31－8220的作用相反,使cNOS mRNA的表达明显升高（P＜0．01）。NO激活剂左旋精氨酸（L－Arg)和抑制剂N^ω－硝基－L－精氨酸甲酯（L－NAME）对PKC-α mRNA的表达无明显影响。结论 PKC可抑制cNOS mRNA在低氧PASMC中的表达。PKC在低氧性肺动脉高压的形成机制中的作用可能是通过抑制cNOS mRNA在PASMC的表达和对NO的调控来实现的,PKC信号通道可能作用在NO的上游,但其机制还有待于进一步的研究。

A study of the effect of protein kinase C on the expression of nitric oxide synthase mRNA in pulmonary artery smooth muscle in hypoxia

OBJECTIVE: To investigate the effect of PKC on the expression of NOS mRNA in pulmonary artery smooth muscle cell(PASMC) in hypoxia. METHODS: RT-PCR was used to detect the expression of PKC alpha mRNA in PASMC of procine, and the effect of activator and inhibitor of PKC on the expression of cNOS mRNA in PASMC. RESULTS: The expression of PKC-alpha mRNA was higher in the PASMC in 48 and 72 h of hypoxia(P < 0.01), and the expression of cNOS mRNA was lower(P < 0.01). The expression of cNOS mRNA was significantly negatively correlated with the expression of PKC-alpha mRNA(P < 0.001). PMA, an agonist of PKC could reduce the expression of cNOS mNRA in hypoxia, while RO 31-8220, an inhibitor of PKC could inhibit it and enhance the expression of NOS mRNA(P < 0.01). The activator of NO, L-Arg and inhibitor, L-NAME had no effect on expression of PKC-alpha mRNA. CONCLUSION: The PKC can inhibit the expression of cNOS mRNA in PASMC in hypoxia. The effect of PKC in hypoxic pulmonary hypertension may be made by inhibiting the expression of cNOS mRNA and modulating NO. The site of the effect of PKC may be in upstream of NO. The mechanism of it needs to be studied further.