Effects of nimesulide on testicular functions in prepubertal albino rats

Daily consumption of painkillers has almost become a routine in many parts of Africa and Asia due to manual labor, especially in young adults. In view of the wide-scale use of painkillers in many parts of Africa and Asia, it is feared that the use of nimesulide may constitute an appreciable public health risk. The present work is aimed at assessing the long-term testicular toxicity of nimesulide in growing male albino rats.

Male albino rats aged 4-5 weeks and weighing between 36 and 42 g were obtained from the Toxicology Unit of the Department of Pharmacology, Faculty of Pharmacy University of Nigeria, Nsukka, Nigeria. The animals were housed singly in a cross-ventilated room at a temperature 22°C±3°C and a 12-h light/12-h dark cycle. They were fed with standard rat pellets (Pfizer Pharmaceuticals, Ikeja, Nigeria) and were given water ad libitum. The rats were divided into three groups of five rats each: the first and second groups orally received 5 and 7.5 mg/kg/day of nimesulide, respectively, whereas the third group did not receive any drug and acted as controls for 56 days. Weekly body weight of each rat was taken. Blood samples were collected on the 56th day by cardiac puncture, and serum samples were frozen until analysis. Rats were sacrificed under ether anesthesia. Epididymal semen number was counted using a Neubauer counting chamber. Sperm motility was assayed microscopically within 5 min at 37°C. Estradiol and testosterone were analyzed with electrochemiluminescence immunoassay using Elecsys autoanalyzer, model 1010 (Roche, Mannheim, Germany). The testes were excised, weighed, and fixed in Bouin fluid and processed for histopathology.

Treatment with nimesulide did not significantly affect body weight, absolute and relative testis weights, or epididymal sperm number, but there were significant differences in testosterone and estradiol levels. At the doses studied, there were no significant changes in testicular architecture except for mild degenerative changes.

In conclusion, nimesulide at normal therapeutic doses may not be spermatoxic, but it is feared that at higher doses, it may have testicular toxicity in albino rats.