藤梨根提取物对HT-29荷瘤裸鼠的抑制及诱导凋亡作用的影响

目的:研究藤梨根提取物(ethanol extract from radix of Actinidia chinensis,EERAC)对人大肠癌HT-29荷瘤裸鼠移植瘤的抑制和诱导凋亡作用.方法:提取EERAC,以大肠癌HT-29细胞对40只Balb/c-nu/nu裸鼠进行荷瘤造模,并随机将分为3个EERAC处理组(低剂量组5mg/kg、中剂量组10mg/kg、高剂量组20mg/kg),空白对照组(生理盐水)和阳性对照组(5-Fu,25mg/kg),每组8只,连续用药8d后,测定各实验组的肿瘤抑制率、脾脏指数.通过脾脏效应细胞培养,测定NK细胞的活性度.免疫组织化学法测定各组荷瘤裸鼠体内凋亡相关基因Bcl-2、Bax、Caspase-3的蛋白表达水平.结果:与空白对照组相比,EERAC对HT-29移植瘤均有明显的抑制作用,各剂量组的抑瘤率为9.12%、20.13%、37.81%,与药物剂量呈正比;EERAC各剂量组对荷瘤裸鼠脾脏指数较生理盐水组和5-Fu组有显著增加(P<0.05);不同剂量的EERAC均可使NK细胞活性度增加(P<0.05);EERAC作用后,HT-29荷瘤裸鼠体内的Bcl-2表达减弱,Bax、Caspase-3表达水平增高,Bcl-2/Bax比值下降,其作用也呈剂量相关性.结论:EERAC对大肠癌细胞HT-29荷瘤裸鼠具有抑制瘤体生长和诱导癌细胞凋亡的作用,其作用机制可能为抑制荷瘤裸鼠体内Bcl-2的表达,提高Bax、Caspase-3表达水平,下调Bcl-2/Bax.EERAC对荷瘤裸鼠免疫系统无不良影响,且能一定程度上提高机体的免疫功能.

Effect of ethanol extract from radix of Actinidia chinensis on tumor growth and cell apoptosis in HT-29 human colon cancer xenografts in nude mice

AIM:To explore the regulatory effect of ethanol extract from radix of Actinidia chinensis(EERAC) on tumor growth and cell apoptosis in HT-29 human colon cancer xenografts in nude mice.METHODS:Forty Balb/c-nu/nu nude mice were used to prepare xenograft models of HT-29 human colon cancer,and model mice were randomly divided into f ive groups(n = 8),including three treatment groups(treated with 5,10 and 20 mg/kg of EERAC,respectively),normal control group(treated with normal saline) and positivecontrol group(treated with 5-FU,25 mg/kg).After 8 d of treatment,spleen index and tumor inhibition rate were determined;the degree of NK cell activity was measured by culturing spleen effect cells;and the expression of apoptosis-related proteins Bcl-2,Bax and Caspase-3 in tumor tissue was determined by immunohistochemistry.RESULTS:Compared to the control group,EERAC treatment had obvious inhibition on the growth of HT-29 xenograft tumor.The inhibition rate for each dose group was 9.12%,20.13% and 37.81%,and there is a positive correlation between tumor growth inhibition and drug dose.Compared to the saline group and 5-Fu group,EERAC treatment significantly increased the spleen index(all P < 0.05) and the activity of NK cells(all P < 0.05),decreased the expression of Bcl-2 and Bcl-2/Bax ratio,and up-regulated the expression of Bax and Caspase-3 in a dosedependent manner.CONCLUSION:EERAC inhibits tumor growth and induces cell apoptosis in HT-29 human colon cancer xenografts in nude mice possibly via mechanisms associated with the inhibition of Bcl-2 expression,lowering of Bcl-2/Bax ratio,and up-regulation of Bax and Caspase-3 expression.