夏枯草提取物对甲状腺癌细胞株B-CPAP凋亡的促进作用及其机制
The pro-apoptotic effect and mechanism of Prunella Vulgaris extracts on thyroid cancer cell line B-CPAP

摘要：目的 观察夏枯草提取物(prunella vulgaris extracts, PVE)对甲状腺癌细胞株(B-CPAP)凋亡的影响，并探讨其相关机制。方法 不同浓度的PVE作用于B-CPAP细胞72h后，MTT法检测细胞活性，计算半数抑制浓度(IC50)；流式细胞术、原位末端标记法(TUNEL)和透射电镜观察在PVE的IC50浓度下作用48h，凋亡率、凋亡指数(AI)及细胞内超微结构的改变；免疫组织化学染色法(IHC)检测PVE作用前后凋亡相关蛋白bcl-2的表达差异。结果 PVE对B-CPAP生长有明显抑制作用(F=22.815，P<0.05)，且抑制作用呈浓度依赖性(r2=0.851)，IC50=1.53mg/mL；流式细胞术检测0.77、1.53mg/mL两个剂量组凋亡率分别为8.5%、16.3%，明显高于对照组的3.9%(P<0.05)；TUNEL法检测凋亡指数(AI)，用药组47%，阴性对照组29%；透射电镜观察PVE处理后的B-CPAP细胞，发现胞内线粒体肿胀且大小不均一，自噬体数量增多；IHC结果的半定量分析发现，阴性对照组细胞胞质bcl-2蛋白的表达量较用药组增多。结论 在体外条件下，PVE对B-CPAP细胞凋亡有显著促进作用；PVE的促凋亡作用可能与抑制bcl-2蛋白表达有关。
ABSTRACT: Objective To observe the pro-apoptotic effect of Prunella Vulgaris extracts (PVE) on thyroid cancer cell line B-CPAP and explore its mechanism. Methods After cultured in PVE of different concentrations for 72h, the cytoactive of B-CPAP cells was detected by MTT and half maximal inhibitory concentration (IC50) was calculated. Flow cytometry, TUNEL and transmission electron microscopy were used to observe the changes in apoptosis rate, apoptosis index (AI) and intracellular ultrastructure after 48-hour treatment with the IC50 concentration of PVE. Immunohistochemical staining (IHC) was used to detect the differences in bcl-2 protein expression with or without PVE treatment. Results PVE significantly inhibited B-CPAP (F=22.815, P<0.05) in the concentration-dependent manner (r2=0.851) with IC50=1.53mg/mL. The apoptosis rate of cells in PVE of 0.77mg/mL and 1.53mg/mL was 8.5% and 16.3%, respectively, which were significantly higher than that of control group (3.9%) (P<0.05). The AI of cells in medium containing PVE was 47% while AI of negative control was 29%. The B-CPAP cells treated with PVE were observed to have swollen intracellular mitochondria, non-uniform size, and an increased number of autophagosomes. Semi-quantitative analysis of IHC showed that the expression level of bcl-2 protein in the negative control group was higher than that in drug group. Conclusion PVE can significantly promote the apoptosis of B-APAP cells in vitro. The pro-apoptotic effect of PVE may be related to the inhibition of bcl-2 protein expression