Is Peripheral Benzodiazepine Receptor (PBR) Gene Expression Involved in Breast Cancer Suppression by Dietary Soybean Protein
Abstract
The objective was to produce breast cancer model in female rats, fed casein containing diet, by gavage administration of DMBA, and to investigate whether the tumor development is controlled by replacement of casein with soybean protein. Two separate experiments were done. For each experiment, Twenty 21-day old female Sprague Dawley rats were used. They were divided into 4 groups. Animals from groups 1 and 2 received standard AIN-76A diet containing 20% casein and those of groups 3 and 4 received same diet containing 20% soybean protein. Animals of groups 2 and 4 received DMBA in sesame oil by gavage (15 mg per animal). Control animals (groups 1 and 3) received the vehicle. Animals were weighed and palpated twice weekly. At the end of the study (postinjection time of 122 days), the animals were killed by carbon dioxide asphyxiation. All tumors were detected by palpation and at autopsy biopsy specimens were taken for histological analysis. Breast tissues were removed, quickly frozen in liquid nitrogen and stored at -800C for biochemical analysis. Even though multiple tumors were observed in some animals of both groups, the number of tumors per rat was less in soyprotein group than casein group at any time point after DMBA exposure. Incidence of tumors was less in soybean protein group than that in casein group. There was no tumor in any animal which did not receive the carcinogen. Casein group had 20% grade I, 60% grade II and 20% grade III mammary gland adenocarcinoma. However, the soybean group had 100% grade I adenocarcinoma and no aggressive grade II or III. These findings suggest that the soybean protein may protect against the development of a more aggressive mammary gland adenocarcinoma. Furthermore, there was a delay in the development of adenocarcinoma in the soybean group challenged with DMBA in comparison to the animals fed casein and challenged with DMBA.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2004
- Accession Number
- ADA425974
Entities
People
- Salil K. Das
Organizations
- Meharry Medical College