ABSTRACT
Preventive effects of artificial beta-carotene on the development of rat mammary gland adenocarcinomas induced by DMBA were studied in rats maintained on a diet containing beta-carotene at a dose of 2.5 mg per animal within 10 weeks, which was initiated after the carcinogen administration. The carotenoid treatment course caused the following effects: manifestation of adenocarcinomas induced by DMBA was decreased, latent period of neoplasm development as well as the rate of tumor differentiation were increased and metastatic spreading into the regional lymph nodes was inhibited.
Subject(s)
Carotenoids/therapeutic use , Mammary Neoplasms, Experimental/prevention & control , 9,10-Dimethyl-1,2-benzanthracene , Animals , Lymphatic Metastasis , Mammary Neoplasms, Experimental/chemically induced , Mammary Neoplasms, Experimental/pathology , Rats , beta CaroteneABSTRACT
DMBA-induced mammary tumours in rats are mixed adenocarcinomas with various growth rate (rapid, slow and stabilized). The electron-microscopic study has shown that ultrastructure of tumours and their growth rate depend on a degree of the parenchyma cell differentiation and on the maturity of connective tissue being the result of their specific interaction.
Subject(s)
Adenocarcinoma/ultrastructure , Mammary Glands, Animal/ultrastructure , Mammary Neoplasms, Experimental/ultrastructure , 9,10-Dimethyl-1,2-benzanthracene , Animals , Epithelium/ultrastructure , Female , Mammary Neoplasms, Experimental/chemically induced , Microscopy, Electron , RatsABSTRACT
The experiments used rats with mammary tumors induced by intravenous injection of DMBA. The animals were treated with alternating courses of estrogen and anti-estrogen (tamoxifen). The former was given in combination with papaverin and low doses of vitamin A. This was followed by light and electron microscopic examination of breast tumors which revealed activation of cell differentiation and tissue-specific function. The death of cells (active autolysis) was similar to one taking place in the course of physiologic involution of the organ but it was unlike liquefying and coagulation necrotic processes usually occurring in tumor.
Subject(s)
Mammary Neoplasms, Experimental/pathology , 9,10-Dimethyl-1,2-benzanthracene , Animals , Cell Differentiation , Cell Survival , Estrogens/administration & dosage , Mammary Glands, Animal/pathology , Mammary Neoplasms, Experimental/chemically induced , Mammary Neoplasms, Experimental/drug therapy , Papaverine/administration & dosage , Rats , Tamoxifen/administration & dosage , Vitamin A/administration & dosageABSTRACT
Structural changes in the mammary gland cells have been studied in rats electron microscopically during pregnancy and involution process after cessation of lactation, as well as at initiation processes by means of abortion at various time of pregnancy (on the 8th, 13th, 20th days). The involutional processes are demonstrated to depend on differentiation degree of the mammary gland cells: intensity of autolytic processes is essentially higher at abortion performed at late stages and at cessation of lactation. Stages of physiological death of the cells are followed. Vitamin A effect on the processes of differentiation and involution is investigated.
Subject(s)
Abortion, Veterinary/physiopathology , Lactation/physiology , Mammary Glands, Animal/physiology , Vitamin A/pharmacology , Animals , Cell Differentiation/drug effects , Female , Mammary Glands, Animal/drug effects , Mammary Glands, Animal/ultrastructure , Microscopy, Electron , Pregnancy , Rats , Time FactorsABSTRACT
gamma-Irradiated rat mammary tumours induced by DMBA are likely to enhance the level of differentiation and to lose their malignant properties when stimulated to differentiation by neuroendocrine factors.