EFFECTS OF ANTIDOTAL THERAPY ON TESTIS TISSUE IN ORGANOPHOSPHATE POISONING UMUT GUMUSAY 1 , AHMET SEBE 2 , DENIZ AKA SATAR 3 , MEHMET OGUZHAN A Y 4 , MUSTAFA YILMAZ 5 , UFUK OZGU METE 6 1 Cukurova Askim Tufekci State Hospital, Emergency Medicine Service, Adana - 2 Cukurova University, School of Medicine, Department of Emergency Medicine, Adana - 3 Adana Numune Education and Research Hospital, Andrology Laboratory, Adana - 4 Adana Numune Education and Research Hospital, Department of Emergency Medicine, Adana - 5 Necip Fazil State Hospital, Emergency Medicine Service, Adana - 6 Cukurova University, School of Medicine, Department of Histology and Embriyology, Adana, Turkey Introduction Widely usage of Methamidophos and other organophosphate derivative insecticides for agricul- ture leads to environment and air pollution, threatens human health. The consumption of food contaminat- ed with Methamidophos, inhalation and skin contact with these compounds or the use in a variety of ways for attempting suicide leads cellular and biochemical toxicity in humans and other organisms (1) . Besides cellular destruction due to toxic effects on various organs such as nervous system (2) , skin (3) , liver (4 ), kidney (5) ; organophosphorus compounds are reported to adversely affect embryonic develop- ment (6) and have toxic effects on female (7) and male reproductive system (8) of mice in experimental condi- tions. With the realization of cessation of spermato- zoon production due to pneumonia in humans (9) , many researchers have turned to study changes on testicles made by a wide variety of different toxic agents. Indeed, it was reported that carbosulfan caus- es impairment in testicular function, decrease level of follicle stimulating hormone (FSH) that plays a role in spermatogenic development and cause reduc- tion in number of spermatozoon by toxic effects (10) . In addition, especially regarding the results of intense studies focusing on semen parameters, a significant decrease in semen quality and an increase in abnor- mally shaped sperm have been reported (11,12) . Although there are studies regarding toxic effects of organophosphorus compounds on different organs and tissues and ultrastructural changes in the testis (8,13,14) , there are no studies indicating whether these effects are reversible with treatment or not. Acta Medica Mediterranea, 2014, 30: 435 ABSTRACT Aims: The study was aimed to clarify whether toxic effects of organophosphorus compounds on ultrastructural changes in the testis tissue are reversible with antidotal treatment or not. Materials and methods: In this prospective, controlled, electron microscopic animal study, Wistar albino adult male rats were divided into 3 groups. 1st group received only isotonic sodium chloride. 2nd and 3rd groups received lethal dose of [(LD50) = 30 mg / kg] Methamidophos. 3rd group was treated with atropine and pralidoxime after cholinergic signs had evolved. Results: In testicular tissue samples of rats in 2nd group, we have found structural degenerative changes. The giant lipid droplets, dense mitochondria, agranüler endoplasmic reticulum vacuolization have been observed. The thickness of membrana pro- pria and electron density of Sertoli have been increased. Also findings of cytoplasmic lysis in most of the tubules, arrest in spermato- genic cells, immature release to lumen and apoptotic changes have been detected. In samples of 3rd group, degenerative changes in testicular tissue were similar to the 2nd group, and no significant structural improvement was proved after treatment. Conclusion: Our study revealed that acute exposure to Methamidophos causes important degenerative changes in all elements of testicular tissue; and those structural degenerative changes are not reversible with pharmacological drug treatment in the acute phase. Key words: Methamidophos; poisoning; organophosphates; testis; infertility. Received January 18, 2014; Accepted January 24, 2014