Study Of Xiaorukuai Capsule On Mammary Carcinogensis Induced By 9, 10-Dimethlben (a) Anthracene (DMBA) In Rats

Background and Objective:Breast cancer is the most common disease in women and it's incidence has been increasing steadily in our country. Because the cause of breast cancer is more complicated then we thought, study on the pathogenesis of breast hyperplasia and carcinoma is the key works for the prevention and treatment of breast cancer. The Chinese medicine "Xiao Ru Kuai" capsule have been proved efficiently on the treatment of breast hyperplasia and relieving the breast pains. We observed the molecular pathological characteristic (the expression of ER α, ERβ, PR, HSP70) on breast cancer induced by 9,10-dimethylben(a) Anthracene (DMBA) in rats, and the effects of "Xiao Ru Kuai" capsule on breast carcinogenesis. The arm is to find out the mechanism of chemical carcinogenesis of breast cancer and the prevention by "Xiao Ru Kuai" capsule. Methods:1. 50 days old female Sprague-Dawley rats were randomly divided into 4 groups: negative control group, model group, low dose group and high dose group.2. The model group, low dose group and high dose group were given DMBA by intragastric administration (15 mg in 1.5 ml sesame oil, twice, one week interval). At the same time, the rats in low and high dose group were given the "XiaoRu Kuai" capsule (0.4g/kg/d and 2.0g/kg/d respectively)by intragastric administration. The negative control group and model group were given 5% sodium carboxymethy -lcellulose(CMC)in the same volume.3. We observed the body weight and mammary neoplasma. The rats were killed in 11th and 14th week respectively.4. The breast tissue or neoplasma were observed by routine pathology (HE stain). Immunohistochemical method detect the expression rate of Erα, Erβ, PR and HSP70 in tumor and mammary dysplasia tissue.Results:1. The weight gain was slower in model group and treatment group (low dose and high dose) than negative control group, but was quicker in low dose group compared with model group and high dose group.2. The mammary neoplasma rate was similar in model group, low dose group and high dose group. But the atypical hyperplasia rate is higher in model group than low dose and high dose group at 11th week, 26.7% (4/15), 0.0% (0/14) and 0.0% (0/15) respectively.3. The mammary carcinogenesis rate also was higher in model group than low dose group at 14th week(P < 0.05), 71.4%(5/7) vs 25.0% (2/8).4. The expression rate of ER α , ER β , PR and HSP70 in the mammary carcinoma and hyperplasia tissue was 0.0%, 52.2%, 100.0% and 87.0% respectively.5. The expression rate of ER β was lower in the mammary carcinoma than in the mammary hyperplasia ( 33.3% and 66.7% respectively), especially in the low dose group, 0.0%(0/2) in carcinoma and 75.0% (3/4) hyperplasia.Conclusion:1. The low dose "Xiao Ru Kuai" capsule could inhibit the mammary carcinogenesis induced by DMBA.2. The mammary cancer induced by DMBA was hormone-dependent.