微囊藻毒素LR和黄曲霉毒素B＿1对肝脏促癌作用的实验研究

LIVER TUMOUR PORMOTION BY MICROCYSTIN LR ANDAFLATOXIN B1 IN TWO-STAGE MEDIUM-TERM ANIMALTEST

为评价微囊藻毒素ＬＲ（ＭＣＬＲ）和黄曲霉毒素Ｂ＿１（ＡＦＢ＿１）对大鼠肝脏的促癌作用,采用二阶段中期动物试验模型进行了研究。６周龄雄性Ｆｉｓｈｅｒ３４４大鼠腹腔注射二乙基亚硝胺（ＤＥＮ,２０Ｏｍｇ／ｋｇ）作为起始剂,在第２周未腹腔注射ＡＦＢ＿１（０.５ｍｇ／ｋｇ）,第３周至第８周每周２次腹腔注射ＭＣＬＲ（ｌ或１０μｇ／ｋｇ）。所有大鼠在第３周末进行２／３部分肝切除,第８周末全部处死,通过在肝切片上测量单位面积肝组织中胚胎型谷胱甘肽８转移酶（ＧＳＴ－Ｐ）阳性灶的数量和面积作为肝脏癌前病变的指标。结果表明ＭＣＬＲ和ＡＦＢ＿１在ＤＥＮ起始下能显著增加ＧＳＴ－Ｐ阳性灶的数量和面积,ＭＣＬＲ单独作用也能显著增加ＧＳＴ－Ｐ阳性灶的面积,提示ＭＣＬＲ为大鼠肝脏的促癌剂,并且ＭＣＬＲ与ＡＦＢ＿１具有协同促癌作用。这对肝癌高发区动员居民改饮沟塘水为深井水有现实意义。

In order to evaluate liver tumour promotion activity of two natural toxins micro-cystin LR(MCLR)and aflatoxin B1(AFB1),a two-stage medium-term animal test wascarried out. 6 week old Fisher 344 male rats were given a single intraperitoneal(i.p.) injec-tion of deithylnitrosamine(DEN, 200mg/kg)as an initiator, followed by i.p。injection ofAFB1(0. 5mg/kg) at week 2.Different doses of MCLR(1μg/kg or l0μg/kg) were i.p,ad-ministratered twice a week from the third week of the experiment. All rats were partiallyhepatectomed at the end of third week and sacrificed at week 8. Glutathione S-transferaseplacental form(GST-P) positive foci as a preneoplasm marker were detected on liver sec-tions。 The results showed that MCLR and AFB1 significantly enhanced both the numbers andareas of GST-P positive foci. Besides, MCLR(10μg/kg) alone also enhanced the areas ofGST-P positive foci. The experiment indicated that MCLR is a liver tumour promoter andmay play synergistic effect with AFB1 It is strong evidence for advise people changing theirdrinking water sources from pond-ditch to deep well。