RESUMO
The best-known and often used systemic, broad-spectrum neonicotinoid pesticide is imidacloprid (IMI). This study was carried out on adult male rabbits (n = 12) to assess the residual effects of exposure to IMI-contaminated diet on the liver, lung, heart, and kidney. Pesticide-exposed rabbits (n = 6) received IMI contaminated green grass (Bildor® 0.5 ml (100 mg)/L water) every alternative day once daily for up to 15 days. The remaining rabbits were fed a standard diet free of pesticides as a control. During routine monitoring of the rabbits throughout the experiment, there were no apparent toxic symptoms identified. On days 16, after deep anesthesia blood and visceral organs were collected. The levels of hepatic serum aspartate transaminase and alanine transaminase were considerably elevated in IMI-exposed rabbits (p ≤ 0.05). Thin layer chromatography revealed that the residue of IMI was at the detectable level in the liver and stomach. Histopathologically, the liver revealed coagulation necrosis with granulomatous inflammation and congestion in portal areas with dilated and congested central veins. The lungs showed congestion of blood vessels and granulomatous inflammation around the terminal bronchiole. Accumulations of inflammatory cells were observed in the cortico-medullary junction in the kidney. The heart showed necrosis and infiltration of mononuclear cells within the cardiac muscles. The findings of the current study emphasize that IMI-contaminated feed exposure causes toxicity into the cellular level of different visceral organs of adult male rabbits and it may also cause the similar toxic effects of the other mammals specially the occupationally exposed persons.
RESUMO
This research was undertaken to assess the results of repeated exposure to the insecticide; imidacloprid (IMI)-contaminated feed on testicular tissue, spermatogenic cell population, Leydig cell number, and sperm morphology in adult male rabbits (n = 24). The treatment groups received IMI (Bildor® 100 mg/L water spray on green grass)-contaminated green grass without wash (n = 8, not-washed-feed rabbit group) and after wash (n = 8, washed-feed rabbit group) once daily for two weeks on an alternate day basis. The rest of the rabbits, as control, received a normal pesticide-free standard feed. During the exposure time, there was no evident toxic symptom found on regular monitoring of IMI-treated rabbits. Histopathologically, the thickness of tunica albuginea of testes reduced significantly with loosely arranged connective tissues in IMI-treated rabbits. Within the testes, the bizarre-shaped seminiferous tubules were seen with increased lumen diameter in IMI-treated rabbits. The spermatogenic cells were disorganized and detached from the basement membrane in seminiferous tubules of IMI-exposed testes of rabbits. The spermatogenic cell population decreased significantly (P < 0.05) in IMI-treated rabbits compared to control rabbits. Leydig cell number decreased significantly (P < 0.05) in IMI-treated rabbits. A high percentage of morphologically abnormal spermatozoa was seen in IMI-treated rabbits. The degree of the histopathological changes was more prominent in the testes of IMI-exposed not-washed-feed rabbits. The results showed that insecticide-IMI has toxicological effects on testicular tissues, mainly spermatogenic and Leydig cell population of adult rabbits which may cause infertility. A short running title: Effect of imidacloprid on testicular tissue of rabbits.
