Chemical castration using an intratesticular injection of mannitol: a preliminary study in a rat model

Authors: MOHAMMAD-ALI MAADI, MEHDI BEHFAR, AMIR RASAEI, ALI SHALIZAR-JALALI, GHOLAMREZA NAJAFI, VAHID MOHAMMADI

Abstract: This study was aimed to evaluated chemical sterilization using an intra-testicular injection of mannitol 20% in rats. Fifty male Wistar rats were divided into five groups, including 1) intact, 2) surgical castration and, 3 to 5) intra-testicular injections of normal saline, hypertonic saline, and mannitol, respectively. The baseline testosterone levels were measured. Surgical castration was performed in group 2. Intra-testicular injections were performed in groups 3, 4, and 5. On day 60, the testosterone level was evaluated. Then, sperm count, viability, motility, morphological abnormalities and DNA damage were studied. Gonadosomatic index was recorded on day 60. Serum testosterone level was significantly decreased in hypertonic saline and mannitol groups compared to the intact and normal saline groups. Severe testicular atrophy, tubular depletion, vacuolization, the formation of multinucleated giant cells, and testicular congestion were noted in the mannitol group. No live spermatozoa were found in groups 4 and 5. Significant reduction in sperm count and morphologic abnormalities were observed in the mannitol group. Gonadosomatic index in groups 4 and 5 were significantly decreased. Severe dehydration and osmotic shock due to the intra-testicular injection of mannitol resulted in testicular degeneration and spermatogenesis disturbance. It could be concluded that intra-testicular injection of mannitol could effectively induce infertility in male rats.

Keywords: Chemical castration, mannitol, rat, sperm, testosterone

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