Histopathology of mammary tumours in female rats treated with 1-methyl-1-nitrosourea.
OBJECTIVE
To induce, evaluate and classify advanced stages of mammary gland tumours induced by MNU.


METHODS
Female Sprague-Dawley rats were injected intraperitoneally with 1-methyl-1-nitrosourea (MNU; 50 mg.kg-1) on the day 33, 40, 47, 54 and 61 of age in the first experiment and on 50th and 113th day in the second experiment. On the 117th day (first experiment) and on the 153rd day of age (second experiment) the rats were sacrificed by decapitation and their mammary glands were evaluated both macroscopically and microscopically for the presence of grossly detectable mammary tumours. Mammary tumours were classified according to Russo et al. (1990).


CONCLUSIONS
The final incidence of palpable carcinomas was ranging from 60 % to 76 %. All microscopically evaluated tumours were malignant. Among the total number of lesions classified the percentage of invasive tumours ranged from 35 % to 44 %. No metastases were observed in other organs in MNU treated animals.
Liska
J
J
Institute of Histology and Embryology, Medical Faculty, Comenius University, Bratislava, Slovakia.
Galbavy
S
S
Macejova
D
D
Zlatos
J
J
Brtko
J
J
D000230:Adenocarcinoma / Q000139:chemically induced / Q000473:pathology; D000818:Animals; D002277:Carcinoma / Q000139:chemically induced / Q000473:pathology; D002278:Carcinoma in Situ / Q000139:chemically induced / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000139:chemically induced / Q000473:pathology; D002291:Carcinoma, Papillary / Q000139:chemically induced / Q000473:pathology; D005260:Female; D008321:Mammary Glands, Animal / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology*; D008770:Methylnitrosourea; D051381:Rats; D017207:Rats, Sprague-Dawley
D008770:Methylnitrosourea