SUMMARY:We evaluated the sperm parameters such as cauda epididymis weight, sperm count, sperm morphology and sperm DNA stability of adult CF-1 male mice treated daily (oral exposure) with the toxic sodium arsenite (As, 7.0 mg/kg/body weight); Melatonin (Me, 10.0 mg/kg/bw), Me (10.0 mg/kg/bw) plus As (7.0 mg/kg/bw) and Negative Control (NaCl 0.9%) to assess acute (8.3 days), chronic (33.2 days) and recovery of testicular damage (66.4 days). Arsenic decreases the number of sperm from chronic treatment (33.2 days) and this effect continued until 66.4 days of treatment. The toxic effect of As also altered the morphology of spermatozoa in all treatment periods when compared to the negative control group. However, Metalonin induced protective effects in periods of 33.2 and 66.4 days of treatment. Additionally, the stability of DNA was significantly affected by arsenic in all periods, but the chronic treatment (33.2 days) in the AsMe revealed increased stability compared to the group treated with arsenic only. Melatonin partially protects sperm toxicity caused by Arsenic, especially during periods of 33.2 and 66.4 days. 1252In this work, we aim to determine the effects of acute, chronic and recovery of testicular exposure to sodium arsenite in epididymal sperm and assess the use of melatonin as a protective agent and antioxidant. MATERIAL AND METHODThree-month-old male mice (Mus musculus) strain CF-1, healthy and sexually mature, were obtained from the Faculty of Medicine, University of Chile. The animals were maintained in a room under controlled conditions of temperature (22±2°C), and a 12 h light/dark cycle, with ad libitum access to commercial pellets and tap water.Reproductive changes were studied as acute (8.3 days), chronic (33.2 days) and recovery of testicular damage (66.4 days) in 88 adult mice exposed every day to oral doses of Sodium Arsenite (As; 7.0 mg/kg/bw, Sigma Chemical Co., St. Louis, MO); Melatonin (Me; 10.0 mg/kg/bw, Arama Laboratorios SA, Santiago, Chile) (Gutelkin et al., 2001); Me (10.0 mg/kg/bw) plus As (7.0 mg/kg/bw), and Negative Control (NaCl 0.9%) delivered orally in a volume not greater than 0.05 mL.Before the beginning and after the end of treatment, all animals were weighted. Euthanasia was performed by cervical dislocation after anesthesia with ketamine (Laboratory Biosano SA, Santiago, Chile) according to the protocol of animal handling of the Bioethics Committee of the Faculty of Medicine, University of Chile. Sperm Parameters.Extraction, weighing and sperm count in epididymalcauda. After obtaining the cauda epididymis they were weighed. Then sperm suspension was obtained using the protocol by Fornés & Bustos-Obregón (1994). Sperm were counted at 200X in a microscope, equipped to use Makler® chamber, adding a drop of sperm suspension by capillary and counting in duplicate the sperm present in the 100 squares of the camera, expressing this result as a million sperm/mg epididymis. Sperm morphology analysis.From the sperm suspension obtained above it was obtained 200 µL of sample. Addit...

SUMMARY:Arsenic is a testicular environmental toxic. Melatonin (Me), being a potent antioxidant, may reduce the damage caused by arsenic in male fertility. The effects of daily oral exposure of Sodium Arsenite (As; 7.0 mg/kg/bw); Melatonin (Me, 10.0 mg/ kg/bw); Me (10.0 mg/kg/bw) plus As (7.0 mg/kg/bw), and Negative Control (NaCl 0.9%) in male CF-1 adult mice were assessed in acute (8.3 days), chronic (33.2 days) and recovery (66,4 days) of testicular damage. We evaluated changes in testicular weight and histopathological, morphometric measurements, expression of COX-2 and Androgen Receptor (AR) antigens and lipid peroxidation levels. Treatment resulted in decreased tubular diameter and AR expression, and increased: interstitial area, luminal diameter, COX-2 expression levels and of lipid peroxidation. Co-administration of As and Me partially decreased germ cell degeneration and AR expression levels, improving testicular histopathological parameters. These results indicate that As causes toxicity and testicular germ cell degeneration by induction of oxidative stress. Me partially protects from this damage in mouse testis, acting as scavenger of oxygen radical species.