ORIGINAL ARTICLE Impaired reproductive function of male rats infected with Toxoplasma gondii A. Abdoli 1 , A. Dalimi 1 & M. Movahedin 2 1 Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; 2 Department of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Introduction Toxoplasma gondii as an intracellular protozoan is widely prevalent in humans and animals. Feline, including domestic cat serve as definitive host and various warm- blooded animals including humans, act as an intermedi- ate host. Infection generally occurs through consuming food or drink contaminated with oocysts and tissue cysts from undercooked meat. Primary infection is usually sub- clinical but in immunocompromised patients, reactivation of latent disease can cause life-threatening encephalitis. Infection acquired during pregnancy can result in congen- ital toxoplasmosis (Dubey, 2010; Weiss & Dubey, 2009). Moreover, asymptomatic toxoplasmosis is one of another aetiologic manifestation of mental illnesses such as schizo- phrenia and autism spectrum disorder (Torrey & Yolken, 2003; Prandota, 2010). Infertility, defined as the failure of conception after one year of unprotected intercourse, affects 10–15 percent of all couples (Mosher & Pratt, 1991). Infectious agents are able to interfere with the reproductive function in both sexes, also infections of male genito-urinary tract account for about 15% of the case of male infertility (Pellati et al., 2008). Many microorganisms such as bacteria, fungi, viruses and parasites seem to be involved in male repro- ductive failure (Pellati et al., 2008). Toxoplasma gondii is a parasite that can infect male genital tract (Garcia et al., 1996) and is one of the classical conditions known to have a profound adverse effect on female reproductive functions (Jones et al., 2003), but a few studies on the effects of T. gondii on male reproductive parameters were performed. In different studies, T. gondii was detected in semen of goat (Dubey & Sharma, 1980; Santana et al., 2010), dog (Arantes et al., 2009), rabbit (Liu et al., 2006), ram (Teale et al., 1982; Lopes et al., 2009a,b), swine (Moura et al., 2007), bull (Scarpelli et al., 2009) and human (Xiangcai et al., 2000). Also, the venereal trans- mission of T. gondii was observed in some animal models Keywords Male rats—reproductive function—sperm and fertility parameters—Toxoplasma gondii Correspondence Prof. Abdolhossein Dalimi, Department of Parasitology, Medical Sciences Faculty, Tarbiat Modares University, P.O. Box: 14115-111, Tehran, Iran. Tel.: +989123047931; Fax: +892144214240; E-mail: dalimi_a@modares.ac.ir This study was presented in 11th Royan International Congress on Reproductive Biomedicine, 15–17 September, 2010; Tehran, Iran. Accepted: September 3, 2011 doi: 10.1111/j.1439-0272.2011.01249.x Summary Toxoplasmosis is one of the classical conditions known to have an adverse effect on female reproductive functions, but a few investigations into male reproductive parameters have been performed. This work was carried out to study the effects of Toxoplasma gondii on reproductive function in male rats. Male rats were infected with the RH strain of T. gondii tachyzoites, and follow- ing every 10 days from 10 to 70 postinfection (PI), the percentage of body weight to testis weight ratio as well as epididymal sperm parameters (number, motility, viability, and morphology rates), serum testosterone (ST), intratesticu- lar testosterone (ITT), serum lactate dehydrogenase (SLDH), intratesticular lac- tate dehydrogenase and fructose in seminal vesicles and coagulating glands were measured. The results of the study showed sperm motility, viability and concentration rates were significantly decreased temporary after infection up to 70 days. Sperm abnormality was also increased during these days. In addition, temporary alteration in ST, ITT, SLDH, intratesticular LDH and fructose in seminal vesicle and coagulating gland was observed PI. These findings suggest that toxoplasmosis can cause impermanent impairment on the reproductive parameters of male rats. ª 2011 Blackwell Verlag GmbH Andrologia 2012, 44, 679–687 679