刺参酸性黏多糖对小鼠H22肝癌移植瘤Bcl-2和Bax基因表达影响

目的探讨刺参酸性黏多糖（SJAMP）对小鼠H22肝癌移植瘤细胞凋亡的作用及其机制。方法接种H22肝癌细胞于昆明种小鼠右前肢腋部皮下,建立H22肝癌模型。将小鼠随机分为阴性对照组、阳性对照组及SJAMP高、中、低剂量组。无菌条件下取肿瘤组织,计算抑瘤率;透射电镜观察肿瘤细胞超微结构;Real-time PCR及免疫组织化学方法分别检测肿瘤组织中Bcl-2和Bax mRNA及蛋白的表达水平。结果 SJAMP各剂量组肿瘤质量均小于阴性对照组,差异有统计学意义（F=40.56,q=2.36～10.02,P〈0.05）。SJAMP各剂量组肿瘤细胞均出现不同程度的凋亡形态学特征。随着SJAMP剂量增加,Bcl-2表达下调,Bax表达上调,Bcl-2/Bax蛋白比值显著降低,呈现一定的剂量依赖关系（F=184.94～8 775.24,q=3.77～225.69,P〈0.05）。结论 SJAMP可以通过促进细胞凋亡达到抑制肿瘤生长的目的,其作用机制可能与下调Bcl-2的表达,同时上调Bax的表达,使Bcl-2/Bax比值下调有关。

EFFECTS OF STICHOPUS JAPONICUS ACIDIC MUCOPOLYSACCHARIDE ON GENES BCL-2 AND BAX EXPRSSION IN H22-HEPATOMA-BEARING MICE

Objective To study the effects of Stichopus japonicus acidic mucopolysaccharide（SJAMP）on apoptosis in H22-hepatoma-bearing mice and its mechanism. Methods H22liver cancer cells were inoculated in the subcutaneous of right axillary fossa of Kunming mice to create a H22-liver-cancer model.The mice were divided into five groups as negative control group,positive control group,low-dose,medium-dose and high-dose SJAMP groups.Tumor tissues were taken under aseptic condition.Tumor inhibition rates were calculated.Ultrastructure of the tumors was examined using transmission electron microscope.The expressions of Bcl-2and Bax proteins and mRNA in the tumor tissues were detected using immunohistochemical method and Realtime PCR. Results Compared with negative control group,the tumor weights of each-dose SJAMP groups were reduced（F=40.56,q=2.36-10.02,P〈0.05）,and different morphologic features apoptosis appeared.Along with the increase of SJAMP dose,the expression of Bcl-2reduced,that of Bax up-regulated,and Bcl-2/Bax protein ratio declined,showing a certain degree of dosedependent（F=184.94-8 775.24,q=3.77-225.69,P〈0.05）. Conclusion SJAMP can inhibit the growth of tumors by promoting cell apoptosis and its mechanism is probably related to down-regulating the expression of Bcl-2and up-regulating Bax,leading to down-regulation of Bcl-2/Bax ratio.