槲寄生总碱和多糖对黄曲霉菌毒素诱发大鼠肝癌前病变时血清同工酶含量的影响

目的研究槲寄生提取物对黄曲霉毒素B1(AFB1)诱发大鼠肝癌前病变时同工酶含量的影响。方法60只大鼠被分为正常对照组、单纯肝大部切除组、AFB1模型组、槲寄生总碱组和槲寄生多糖组。后3组大鼠一次性ip给予AFB10.75mg·kg-1,第3周起饲以含0.015%二乙酰氨基芴饲料5周。后4组大鼠于第3周末施行肝大部切除术。槲寄生总碱和槲寄生多糖组于肝大部切除术后1周开始分别ig给予槲寄生总碱8g·kg-1和槲寄生多糖6g·kg-1,每天1次,连续给药4周。第8周末处死大鼠,采用组织化学染色法检测肝组织切片中γ-谷氨酰转肽酶(GGT)阳性染色面积;免疫吸附法测定血清GGT同工酶Ⅱ(GGTⅡ)阳性表达;酶速率法和琼脂糖电泳法测定血清乳酸脱氢酶(LDH)和碱性磷酸酶(ALP)总活性及其同工酶相对含量。结果AFB1引起肝脏组织中GGT表达明显增加;大鼠血清GGTⅡ阳性率明显升高;血清LDH总活性和LDH5含量增高,且LDH5>LDH4;血清ALP1含量明显升高,并出现异常ALP电泳条带。大鼠ig给予槲寄生总碱或槲寄生多糖治疗4周,肝脏组织中GGT表达明显减少,血清GGTⅡ阳性率明显下降,血清LDH总活力、LDH5和ALP1含量均较模型组明显降低。结论AFB1诱发的大鼠肝癌前病变有多种同工酶的表达异常,槲寄生总碱和多糖可能通过调节同工酶的表达干预肝癌前病变的发生和发展。

Effects of alkalies and polysaccharides of Viscum album on serum isoenzyme content in precancerous conditions of liver neoplasms of rats induced by aflatoxin B1

AIM To study effects of isoenzyme activity by alkalies and polysaccharides of Viscum album in precancerous conditions of liver neoplasms of rats induced by aflatoxin B1(AFB1). METHODS Sixty rats were divided into normal control group, partial liver resected group, AFB1 model group, total alkalies of mistletoe (TAM) 8 g·kg^-1 group, and polysaccharides of mistletoe （PM） 6 g·kg^-1 group. AFB1 0.75 mg·kg^-1 was ip injected into the abdominal cavity of experimental rats as an initiate agent. After 2 weeks, the test entered a selective promote procedure, which raised rats with 0.015% 2-acetylaminofluorene fed for 5 weeks. According to the classical form of operation, 2/3 part liver of rats were removed in the end of the third week. Rats in TAM and PM groups were ig given TAM 8 g·kg^-1 and PM 6 g·kg^-1 from the first week after greater part liver removed, once a day, for 4 weeks. At the end of the eighth week, all rats were sacrificed under anesthesia with pentobarbital after fasting for 8 h, then the hepatic tissue was taken out at the assigned position which was the right anterior leaf, right back leaf and the caudal leaf, and at the same time blood samples from heart were also collected. γ-Glutamyl-transpeptidase (GGT) isoenzyme was determined with histochemical methods. Serum lactic dehydrogenase (LDH), alkaline phosphatase (ALP), serum γ-glutamyl transpeptidase-isoenzymeⅡ (GGT-Ⅱ) and their isoenzymes were determined with enzyme-velocity method and agarose electrophoresis. RESULTS In AFB1 model group, the focal amount (numbers/cm2) of GGT obviously elevated, positive rate of GGT-Ⅱ increased markedly, total activity of LDH, ALP and GGT increased obviously, and LDH5＞LDH4. Anomalous ALP in electrophoresis was found. After the rats were ig treated with TAM and PM for 4 weeks, the focal amount and areas of GGT were less than those in model group obviously; and the positive rate of GGT-Ⅱ descended obviously in the serum, not only total activities of LDH decreased obviously, but also LDH5＜LDH4; TAM and PM had effects on anastate ALP1 and inhibit expression of ALP1. CONCLUSION Multi-isoenzyme anomal expression is found in precancerosis of liver induced by AFB1, however, TAM and PM can obviously inhibit rat hepatic precancerous conditions, which are aroused by AFB1. This effect is enforced with regulation of multi-isoenzyme by TAM and PM.