超声辐照载紫杉醇微泡对大鼠血管平滑肌细胞凋亡的影响

目的 探讨超声辐照载紫杉醇微泡对大鼠血管平滑肌细胞(VSMCs)凋亡的影响及其作用机制.方法 将体外培养的大鼠胸主动脉VSMCs用血小板衍生生长因子-BB刺激后分组如下:对照组(A组)、超声辐照+微泡组(B组)、超声辐照+载紫杉醇微泡组(C组)、单纯载紫杉醇微泡组(D组)和紫杉醇组(E组).采用频率1MHz、声强0.3W/cm2的连续波超声辐照VSMCs 120s,用流式细胞仪、Annexin V/PI染色和免疫细胞化学技术检测各组细胞周期、细胞凋亡以及凋亡相关蛋白表达的变化.结果 与A组比较,各组S期细胞比例均显著降低(P＜0.01),B组G0/G1期细胞比例显著增高(P＜0.01),D组和E组G2/M细胞比例显著增高(P＜0.01),C组G0/G1期细胞比例和G2/M细胞比例均显著增高(P＜0.01).与A组比较,B组和C组VSMCs凋亡率显著增高(P＜0.01),Bax蛋白表达显著上调、而Bcl-2蛋白表达则显著降低(P＜0.01).结论 超声辐照载紫杉醇微泡可诱导VSMCs凋亡,其机制可能是微泡介导的超声空化效应,致Bax蛋白表达上调及Bcl-2蛋白表达下调.

Effect of paclitaxel-loaded microbubbles triggered with ultrasound irradiation on apoptosis of rat vascular smooth muscle cells

Objective To investigate the effect of paclitaxel-loaded microbubbles （PLM） triggered with ultrasound irradiation on the apoptosis of rat vascular smooth muscle cells （VSMCs） and its mechanism. Methods Rat thoracic aortic VSMCs were treated by platelet derived growth factor-BB, and then randomly divided into five groups as follows： control group （group A）, microbubbles combined with ultrasound irradiation group （group B）, PLM combined with ultrasound irradiation group （group C）, PLM treated group （group D）, and paclitaxel treated group （group E）. VSMCs from groups B and C were exposed to 1 MHz continuous wave ultrasound for 120s at intensity of 0.3W/cm2. The cell cycle, apoptoitc cells and the expression of Bax and Bcl-2 were detected by flow cytometry, AnnexinV/PI staining and immunocytochemical assay, respectively. Results Compared with group A, the number of the cells arrested at S phase was decreased significantly in other groups （P〈0.01）. The percentage of the cells at G0/G1 phase was greatly increased in group B, that of G2/M phase cells was increased remarkably in group D and E （P〈0.01）, and those of G0/G1 phase cells and G2/M phase cells were increased significantly in group C （P〈0.01）. Apoptosis rate was significantly higher in group B and C than in group A （P〈0.01）, while the expression of Bax was increased, and that of Bcl-2 decreased （P〈0.01）. Conclusion Ultrasound triggered PLM induces rat VSMCs apoptosis, which might be due to upregulation of Bax and downregulation of Bcl-2 induced by microbubbles-mediated ultrasound cavitation.