甜菜碱对HepG2人肝癌细胞[Ca2+]i和细胞膜电位的影响

目的研究甜菜碱对肝癌HepG2细胞内游离Ca2 浓度([Ca2 ]i)和细胞膜电位的影响。方法Fluo-3/AM标记,激光扫描共聚焦显微镜观察HepG2细胞[Ca2 ]i,TMRE标记,激光扫描共聚焦显微镜测定细胞膜电位的影响。结果甜菜碱能够升高HepG2细胞[Ca2 ]i,降低细胞膜电位。升高[Ca2 ]i的强度具一定的剂量依赖性,随甜菜碱剂量的增大而升高。甜菜碱50、25mg/mL组与对照组比较差异非常显著(P<0.01),甜菜碱12.5mg/mL组与对照组比较差异显著(P<0.05)。给药48h时间段内细胞内的[Ca2 ]i升高的幅度较大,72h升高幅度相对较小。而降低膜电位上,在48h时间段内,甜菜碱50、25、12.5mg/mL各组膜电位均显著高于对照组(P<0.05),但在72h时间段内甜菜碱12.5mg/mL组与对照组比较没有显著性差异(P>0.05)。结论甜菜碱通过开放细胞膜上的通透性转换孔道(MPTP),从而升高HepG2细胞[Ca2 ]i,启动细胞凋亡机制,诱导HepG2细胞凋亡。

Effects of betaine on [Ca2+]i and potential of cell membrane in HepG2 tumor cells

Objective To study the effects of betaine on [Ca2 ]i and potential of cell membrane in HepG_2 tumor cells. Methods Staining with Fluo-3/AM, [Ca~(2 )]_i in HepG_2 tumor cells was observed by laser scanning confocal microscope, staining with TMRE, membrane potential in HepG_2 tumor cells was observed by laser scanning confocal microscope. Results After treating with betaine, the [Ca~(2 )]_i in HepG_2 tumor cells increased while the potential of cell membrane in HepG_2 tumor cells decreased. The elevate intension of [Ca~(2 )]_i from the divided three groups was in a dose-dependent manner, it will elevate if the betaine dose increases. Compared with the control group, the betaine groups of 50 and 25 mg/mL had the extraordinary significant effect (P<0.01), of 12.5 mg/mL (P<0.05). For the [Ca~(2 )]_i in HepG_2 tumor cells, there was a big increase at 48 h after betaine treatment, but a less increase at 72 h after betaine treatment. For the potential of cell membrane in HepG_2 tumor cells, the betaine groups of 50, 25, and 12.5 mg/mL had the significant effect (P<0.05) at 48 h after betaine treatment, but the group of 12.5 mg/mL had no notable effect (P>0.05) at 72 h after betaine treatment. Conclusion Betaine opens the mitochondrium permeability transition pore (MPTP) to increase the [Ca~(2 )]_i in HepG_2 tumor cells, which could induce the apoptosis.