Effect of Vitamin E on Sperm Motility and Survival in Chilled-Stored Semen


Background:Sperm cells are well equipped with a powerful defense system of antioxidants, but an imbalance between the production of reactive oxygen species (ROS) and the available antioxidant-defenses result in oxidative stress. Therefore, antioxidants are supplemented extracellularly under in vitro conditions. Antioxidants are the main defense factors against oxidative stress induced by free radicals. Vitamin E is believed to be the primary component of the antioxidant system of the spermatozoa and is one of the major membrane protectants against ROS and lipid peroxidation (LPO) attack. It appears to be the first line of defense against the peroxidation of polyunsaturated fatty acids (PUFAs) contained in the cellular and sub-cellular membrane phospholipids because of its lipid solubility.Objective:The aim of the current study to evaluate effects of supplementing semen extender with vitamin E, at various concentrations (2, 6 and 12 IU/ml) on sperm motility, survival and morphology on the releases of free radicals and antioxidant enzymes within semen.Patients ,Materials and Methods:Twenty two patients were involved in the present study semen samples were obtained, and sperm count was assessed. The antioxidant (vitamin E) was formulated to be tested at three different levels as follow; 2, 6 and 12 IU/ml; Therefore, control and 3 antioxidant-containing extenders were prepared for semen dilution. The sample was divided into 4 aliquots. One volume of semen was added to 5 equal volumes of the designed extender. Extended semen samples (37¢ªC) were gradually cooled to 4¢ªC in the refrigerator and stored for 48 hours. A semen sample was taken out after 48h of storage, then warmed to 37¢ªC and checked for progressive motility, viability and abnormality.Sperm viability was assessed by Eosin Y. (0.5%).Nigrosin (0.1%) staining mixture. A total of 200 sperm were assessed under oil immersion with a high-resolution (X100) objective. Sperm morphology was assessed by Hematoxylin- Eosin satin, at least 200 sperm were scored on randomly chosen field, under oil immersion with a high-resolution (X100) objective.Results:The highest post-thaw motility and sperm survival (44% and 51.7%) 48 h after storage at 4¢ªC (Table 1) were attained (P < 0.01) in the basal diluents containing 6 IU vitamin E. Likewise, the correspondent percentages of live spermatozoa were 59%. Contrariwise, percentage of sperm abnormalities for the previous treatment was 25% significantly (P < 0.05) decrease compares with basal diluents containing 2, 12 IU vitamin E. The lowest (P ¡Ã 0.05) survival (23.5%, Table 1) was found in the basal diluents containing 12 IU vitamin. Beyond 6 IU vitamin E, there appears to exert adverse effects on sperm viability and survival.Conclusions:For the best protection against the increased free radicals production during chilling-preservation of human semen, extenders must contain 6 IU vitamin E per ml. The intensive production of free radicals in seminal plasma was counteracted by the inclusion of vitamin E at the above mentioned concentrations.