外源性雌激素及三苯氧胺对大鼠乳腺癌癌前期病变的作用

目的　建立乳腺癌癌前期病变动物模型，探索外源性雌激素（EE）及其拮抗剂的作用。　方法　Wistar雌性大鼠50只，对照组12只；其余大鼠经胃管灌注7，12-二甲基苯并蒽（DMBA），8只用正常饮料(DMBA组)；15只饲料中加乙烯雌酚(DMBA＋DES组)；15只饲料加三苯氧胺(DMBA＋TAM组)。3个月后检测乳腺增生、核仁形成区嗜银蛋白（AgNOR）和DNA含量。　结果　DMBA组和DMBA＋DES组的乳腺组织增生率分别为75％及93.33%;AgNOR计数为3.71±0.76及5.60±0.42;DNA含量为88.59±7.17及137.75±3.13，DMBA组及DMBA＋DES组与对照组和DMBA＋TAM组比较差异有显著意义（P＜0.01）。　结论　一次性灌注DMBA可以建立乳腺癌癌前期病变动物模型；EE可加重DMBA诱导的乳腺癌癌前期病变；而TAM则具有阻断作用。

The effect of exogenous estrogen and tamoxifen on murine experimental precancerous breast disease

Objectiver　 To establish murine breast precancerous model and evaluate the effect of exogenous estrogen and tamoxifen.　 Method　 50 female Wistar rats were divided into contol group (n＝12), the other 38 received low dose carcinogen (DMBA) by gastrogavage, and then divided into DMBA group (common diet,n＝8); DMBA+DES group(DES added chow,n＝15); and DMBA+TAM group (TAM added chow,n＝15). 3 months later, the status of breast hyperplasia, AgNOR and DNA content were measured. 　Results　 All indexs in control group and DMBA+TAM group were normal.However,in DMBA group and DMBA+DES group,the breast hyperplasia rate was 75%, 93.3%, AgNOR was 3.71±0.76, 5.60±0.42, DNA was 88.59±7.17, 137.75±3.13 respectively.Compared with control group and DMBA+TAM group, the differences of indexes in DMBA and in DMBA+DES group were significant (P<0.01). 　Conclusion　 Low dosage DMBA administered by gastrogavage established breast precancerous model. Exogenous estrogen promotes the development of breast precancerous disease induced by DMBA, while TAM suppresses the canceration.