Objective To investigate the effects of ultrasound irradiating hydroxycamptothecin (HCPT)-loaded microbubbles on apoptosis in human hepatoma SMMC-7721 cells, and to clarify its probable mechanism. Methods The SMMC-7721 cells were randomly divided into six groups as follows: control group, blank liposome microbubbles plus ultrasound, HCPT-loaded microbubbles, HCPT, HCPT plus ultrasound,and HCPT-loaded microbubbles plus ultrasound. Apoptosis was ascertained by Annexin V-Fire/ PI and TUNEL methods. The expression of Bcl-2 and Bax protein was detected by immunocytochemistry staining technique. Results In the group of HCPT-loaded microbubbles plus ultrasound,the apoptosis rate at early term was found to reach (12.18 ± 1.38)% by Annexin V-Fitc/PI assay, brown-colored positive apoptotic cells were observed and the apoptosis rate at advanced term was found to reach (34.25 ± 1.83)% with TUNEL method. The expression of Bcl-2 was found to decrease,the expression of Bax increase,and the ratio of Bcl-2/bax significantly decrease by immunocytochemistry staining technique in the same group. Differences with other groups were significant. Conclusions The method of ultrasound irradiating HCPT-loaded microbubbles can notability induce human hepatoma SMMC-7721 cells apoptosis. The decrease in the ratio of Bcl-2 to Bax might be responsible for cells apoptosis.%目的 研究超声辐照载羟基喜树碱微泡对肝癌SMMC-7721细胞凋亡的影响,并探讨其诱导细胞凋亡的分子机制.方法 SMMC-7721细胞随机分为6组,即对照组、空白脂质微泡+超声组、载羟基喜树碱微泡组、羟基喜树碱组、羟基喜树碱+超声组及载羟基喜树碱微泡+超声组.采用Annexin V-FITC/PI双染法和TUNEL法检测细胞凋亡状况;免疫细胞化学法检测Bel-2、Bax蛋白表达.结果 载羟基喜树碱微泡+超声组用Annexin V-FITC/PI检测细胞早期凋亡率为(12.18±1.38)%;TUNEL法显示染成棕黄色的凋亡细胞,细胞中晚期凋亡率为(34.25±1.83)%;免疫细胞化学法检测Bcl-2蛋白表达下降,Bax蛋白表达升高,Bel-2/Bax比值明显下降.以上结果与其他组的检测结果相比,差异具有统计学意义.结论 超声辐照载羟基喜树碱微泡能明显诱导肝癌SMMC-7721细胞凋亡,其机制可能与降低Bcl-2/Bax比值有关.
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