钙超载大鼠肠系膜血管平滑肌细胞钙离子稳态调节的改变

Changes of Handling of Calcium in Mesenteric Vascular Smooth Muscle Cells of Calcium Overload Rat

目的 探讨钙超载模型大鼠血管平滑肌细胞 (VSMC)胞内是否存在钙离子 (Ca2 + )稳态调节异常。方法 以 Fluo- 3/AM作为 Ca2 + 指示剂 ,应用激光扫描共聚焦显微镜技术 ,比较钙超载模型大鼠肠系膜 VSMC(Ca OMV)与正常 Wistar大鼠肠系膜 VSMC(WMV )静息态的胞浆与核内游离 Ca2 + 水平 ([Ca2 + ]i,[Ca2 + ]n) ,以及在多种药物刺激下 Ca2 +稳态调节的差异。结果 两种 VSMC静息态 [Ca2 + ]i及 [Ca2 + ]n 并无显著性差异 ,但在KCl、Bay- k86 44、Ang- 、IP3、CHCl3和 CPA等药物作用下 ,Ca OMV [Ca2 + ]i与 [Ca2 + ]n的升高幅度较 WMV显著增大 (P<0 .0 1)。结论 (1) Ca OMV对激动剂作用的敏感性增强 ,存在 Ca2 + 稳态调节异常 ,提示胞内钙超载与胞外钙超载同时共存 ,是血管硬化和老化机制的两个方面 ;(2 )血管钙超载时 ,VSMC无论质膜上的 Ca2 + 门控系统还是胞内钙池的释放与重储均有异常 ;(3)在 Ca OMV,胞浆与核内钙的调节均存在异常。

To investigate if there existed abnormal handling of calcium in vascular smooth muscle cells (VSMC) in calcium overload rat (CaOMV). Methods Cytosolic and nuclear calcium ion handling in mesenteric VSMC both in calcium overload rat and in Wistar rat were studied by using laser scaning confocal microscopy together with calcium-sensitive-dye Fluo-3/AM. Results The results showed that both nuclear and cytosolic calcium level ([Ca 2+] n,[Ca 2+] i)in mesenteric VSMC in calcium overload rat under resting condition was not higher than that in normal rat.However,[Ca 2+] n and[Ca 2+] i in CaOMV increased more significantly than that in normal rat when induced by drugs such as KCl,Bay-k8644,Ang-Ⅱ,IP 3,CHCl 3, and CPA. Conclusions (1) There exists abnormal handling of calcium in CaOMV because of it's overreaction to stimulators,which indicate that intracellular and extracellular calcium overload coexist in age-related arteriosclerosis;(2) Not only Ca 2+gating system of plasma membrane but also calcium pool in CaOMV are irregular;(3) Cytosolic calcium as well as nuclear calcium are handled improperly in CaOMV.