Experimental model of pulmonary carcinogenesis in Wistar rats.

Purpose: To elaborate an experimental model of pulmonary carcinogenesis in Wistar rats.

Methods: Male Rattus norvegicus albinus, Wistar lineage were carried through an intra-pulmonary instillation of the Benzo[a]pyrene (B[a]P) dilution in alcohol 70%, a polycyclic aromatic hydrocarbon widely known by its power of tumoral induction. Three experimental groups had been formed with 08 animals each: Control Group (Alcohol 70%); B[a]P Group 10 mg/kg; e B[a]P Group 20mg/kg, submitted to euthanasia 08, 10, 12 and 14 weeks after the experimental procedure. The pulmonary sections had been colored by hematoxilin-eosin (HE) and submitted to the morphometrical analysis to describe the tissue alterations.

Results: The presence of diffuse inflammatory alterations was observed in all groups; however, at the analysis of the pulmonary tissue of the experimental groups had been observed hyperplasic alterations (BALT hyperplasia), and in one of the animals of the experimental group 20mg/kg (12 weeks) was noticed the presence of cellular epithelial tracheal pleomorphism, suggesting the adenocarcinoma formation in situ.

Conclusion: The main secondary alterations to the intra-pulmonary instillation of B[a]P in Wistar rats were: cellular proliferation, inflammatory alterations of several degrees and nodular lymphoid hyperplasias. The association of an activator agent of the pulmonary metabolic reply is necessary to establish the ideal reply-dose to the development of the lung cancer.