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目的 :探讨钙信号在尾加压素 Ⅱ (urotensin Ⅱ ,UⅡ )促血管平滑肌细胞 (vascularsmoothmusclecell,VSMC)增殖中的作用。方法 :在离体培养的VSMC上 ,用流式细胞仪和3 H TdR参入的方法探讨UⅡ的促增殖效应 ;在离体孵育的大鼠主动脉平滑肌组织上观察UⅡ对平滑肌45Ca2 + 摄入的影响 ;应用激光共聚焦显微镜检测UⅡ作用后细胞内游离钙的改变。结果 :UⅡ (10 -9～ 10 -7mol·L-1)浓度依赖地刺激VSMC的DNA合成 ,并诱导细胞由静止向增殖状态转化。与对照组相比 10 -8mol·L-1UⅡ使细胞的增殖指数 [(G2 M +S) % ]增加 192 % (P <0 .0 1)。钙通道阻断剂尼卡地平和Ca2 + 螯合剂EDTA均可阻断UⅡ对VSMC的促增殖效应 ,其中UⅡ (10 -8mol·L-1)与尼卡地平 (10 -5mol·L-1)共同孵育的VSMCDNA合成量仅为单纯UⅡ (10 -8mol·L-1)组的 5 9.0 %。UⅡ (10 -10 ～ 10 -8mol·L-1)可浓度依赖地使胸主动脉对45Ca2 + 的摄入增加 ,尼卡地平 (10 -5mol·L-1)也可显著对抗UⅡ (10 -8mol·L-1)对45Ca2 + 摄入的诱导作用 (P值均小于 0 .0 1)。用激光共聚焦显微镜观察发现UⅡ作用后细胞内Ca2 + 浓度迅速升高 ,持续约 3min ,形成钙波。结论 :UⅡ可通过促进细胞Ca2 + 摄取和增加细胞内Ca2 + 浓度 ,发挥其促进VSMC增殖的作用
Objective: To investigate the role of calcium signaling in the proliferation of vascularsmooth muscle cells (VSMC) induced by urotensin Ⅱ (UⅡ). Methods: Proliferation of UⅡ was investigated by flow cytometry and 3H-TdR incorporation in VSMCs cultured in vitro. The effect of UⅡ on the smooth muscle 45Ca2 + uptake was observed in isolated rat aortic smooth muscle. The changes of intracellular free calcium after UⅡ treatment were detected by laser scanning confocal microscopy. Results: UⅡ (10 -9 ~ 10 -7 mol·L-1) stimulated the VSMC DNA synthesis in a concentration-dependent manner and induced the cells to transform from resting to proliferative state. Compared with the control group, 10 -8 mol·L-1UⅡ increased the cell proliferation index [(G2 M + S)%] by 192% (P <0.01). Calcium channel blocker nicardipine and Ca2 + chelator EDTA could both inhibit the proliferation of VSMC induced by UⅡ, in which UⅡ (10 -8 mol·L -1) and nicardipine (10 -5 mol·L -1) The amount of VSMCDNA co-incubated was only 9.09% of the pure UⅡ (10 -8 mol·L-1) group. UⅡ (10 -10 ~ 10 -8 mol·L-1) increased the uptake of 45Ca2 + in the thoracic aorta in a concentration-dependent manner, and nicardipine (10 -5 mol·L-1) 8mol·L-1) on 45Ca2 + uptake (P values were less than 0.01). Confocal laser scanning microscopy showed that intracellular Ca2 + concentration increased rapidly after treated with UII for about 3 min to form calcium wave. Conclusion: UⅡ can promote the proliferation of VSMC by promoting cellular Ca2 + uptake and increasing intracellular Ca2 + concentration