Spontaneous pathological lesions of liver and lungs in preclinical toxicology evaluation studies Qadri Syed S.Y.H., Kumar P. Uday, Sesikeran B. Pathology Division, National Institute of Nutrition, Jamai Osmania P.O., Hyderabad-7. Abstract The need for a toxicopathologist to be aware of spontaneous lesions that may occur in laboratory animals and which may be encountered in the course of a toxicological study are important, as they may be a confounding factor in the final assessment of toxic effects of the test substance used in the study. Hence, spontaneous pathological lesions that occurred mainly in the liver and lungs of laboratory animals, used for preclinical toxicological evaluation of various Drugs/New Chemical Entities were recorded. These were seen both in subchronic and chronic studies conducted in various laboratory animals of our centre and presented in this communication. In the liver, focal lesions of hepatic steatosis (17.5%), focal necrotic areas in hepatic parenchyma (37.5%), periportal inflammatory cell infiltration (81%), cysticercosis (hydatid cyst) (27.7%) and biliary hyperplasia (22.2%) were observed in the mice, rats and rabbits belonging to various studies. In the lungs, peribronchial aggregates of lymphocytes (46.6%) and medial hypertrophy of the pulmonary arteries (8.3%) were observed in Wistar rats and New Zealand white rabbits. All these lesions were distributed equally among both the control and experimented groups and in both sexes. Knowledge of the above situations would help the pathologists to interpret the results obtained in a toxicological study in a better way, and also help the pathologist in avoiding embarrassing situations, with reference to justifying the results obtained in a particular study. Top Key words Liver, lungs, mice, pathology, toxicological evaluation, rabbits, rats. Top |