Browsing by Author "Ferreira, Rita"
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- Histological classification of urothelial lesions chemically-induced in the male rat modelPublication . Faustino-Rocha, Ana Isabel; Pinto, Carla; Vala, Helena; Ferreira, Rita; Oliveira, Paula AlexandraObjective: Bladder cancer is one of the most frequent of the urinary tract. Urinary bladder tumours induced by the N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) are similar to those observed in humans. This work aimed to classify, by histology, the urinary bladder tumours BBN-induced in a rat model. Methods: Procedures were made in accordance with the Directive 2010/63/EU. Eleven Wistar male rats with five weeks of age were used. BBN was administered in drinking water at a concentration of 0.05% water during the first 20 weeks of the protocol. Thirty-five weeks after the start of the protocol, animals were humanely sacrificed by the overdose of pentobarbital sodium. Results: No animals died during the protocol. In the histological analysis of the urinary bladders were identified the following lesions: simple hyperplasia (81.8%), nodular hyperplasia (54.5%), papillary hyperplasia (14%), papilloma (45.4%), papillary neoplasm of low malignant potential (36.4%), low-grade papillary carcinoma (90.9%), high-grade papillary carcinoma (72.7%), invasive carcinoma (14%) and epidermoid metaplasia with keratinization (45.4%). Conclusion: Our team has a vast experience on the bladder cancer animal models; however this is the first protocol in male rats. We concluded that the lesions identified are similar to those observed in Humans.
- Histopathological features of organs in a rat model of mamamry carcinogenesis: a reference databasePublication . Vala, Helena; Nóbrega, Carmen; Gama, Adelina; Ferreira, Rita; Oliveira, Paula A.; Faustino-Rocha, Ana I.Mammary tumors’ development was induced through the intraperioneal administration of the carcinogen N-methyl-N-nitrosourea (MNU). Animals from group control were injected with the vehicle (saline solution). Animals were sacrificed at 25 weeks-old and the organs were histopathologically evaluated. A higher number of lesions was observed in the organs of animals from group MNU. The animals from group control did not present any lesion in lymph nodes. Independently of the experimental group, the internal organs presented hemodynamic alterations, degenerative and inflammatory changes. Hemodynamic changes may be consequence of euthanasia method. As expected, the higher number and the higher grade of the lesions in group MNU were due to the carcinogen administration.