褪黑素对小鼠肝癌细胞凋亡及自然杀伤细胞活性的影响

目的 探讨褪黑素(MLT)在体内对H22肝癌细胞凋亡及免疫调节作用的影响及其机制。方法 应用免疫组织化学染色方法及原位末端脱氧核苷酸转移酶标记法(TUNEL)对Bc1-2、Bax的表达及凋亡细胞进行检酗，MTT比色法检测脾细胞NK杀伤活性。结果 实验发现MLT治疗组、预防组及5-Fu组Bcl-2和Bax的表达及凋亡细胞数明显高于生理盐水组(P＜0．01)。Bax／Bcl-2比例在MLT预防组最大。NK杀伤活性在MLT治疗组、预防组较其它组明显增高(P＜0．05)。结论 MLT在体内有促进肿瘤细胞凋亡的作用，且可使NK杀伤活性增高，推测Bcl-2、Bax和机体的免疫系统参与了褪黑素的抗肿瘤作用。

Role of Melatonin in Apoptosis and NK Activity of Hepatoma Cells

Objective To investigate the effects of melatonin (MLT) on apoptosis and immunomodulation of H22 hepatoma cells in vivo and the mechanism. Methods The methods of immunohistochemistry (IHC) and TUNEL were used to detect the apoptotic cells and the expression of Bcl-2 and Bax. MTT was used to detect the NK activity of splenic cells. Computer image analysis system was used to quantify the expression of Bcl-2 and Bax. Results IHC staining and TUNEL showed that the expression of Bcl-2, Bax and the number of apoptotic cells in the control group were lower than those in the MLT-treated group, MLT preventive group and 5-Fu group. The ratio of Bax/Bcl-2 in MLT preventive group was the highest. MTT showed that the NK activity was higher in MLT groups than other two groups (P<0.05). Conclusion MLT may induce the apoptosis of hepatoma cells in vivo and enhance NK activity, speculating that Bcl-2, Bax and body immunology system were involved in the anticancer effect of MLT.