Australian Journal of Basic and Applied Sciences, 2(3): 773-778, 2008 ISSN 1991-8178 Corresponding Author: Hesham Nabil, Department Of Andrology, Menoufiya University. E-mail: heshamnk@hotmail.com. 773 Studying the Levels of Malondialdehyde and Antioxidant Parameters in Normal and Abnormal Human Seminal Plasma Hesham Nabil, Lekaa A. Moemen and Manal H. Abu Elela, 1 2 3 Andrology Department, Menoufiya University, Medical Biochemistry Dept., 1 2 Research Institute of Ophthalmology, Public Health Dept., 3 Research Institute of Ophthalmology, Egypt. Abstract: Objective: To measure the seminal levels of malondialdehyde and antioxidants in men with both normal and abnormal seminogram. Setting: Andrology Clinic, Dr. Ahmad Fikry Medical Centre, Abu Dhabi, United Arab Emirates. Patients: 34 male subjects with normal and abnormal semen analysis were recruited during the period from November 2007-June 2008. Intervention: Seminal levels of malonadialdehyde, glutathione, ascorbic acid and total antioxidant status were measured for all enrolled men. Results: Malondialdehyde level was significantly elevated in oligozoospermic and azoospermic men while glutathione, ascorbic acid and total antioxidant status were significantly reduced in the previous groups compared to normozoospermic group. Conclusion: Lipid peroxidation plays a significant role in disrupting sperm functions and semen quality especially sperm motility and morphology and may account for some cases of male infertility. Key words: Lipid peroxidation, seminal plasma, male infertility INTRODUCTION Oxidative damage to sperm can reduce sperm motility, interfere with sperm-oocyte binding and fusion and it has been implicated as a cause of male infertility (Agarwal A., S.A. Prabakaran, 2005). Peroxidation damage to the plasma membrane of sperms have been suggested as an important mechanism of male infertility (Aitken R.J., D. Buckingham, et al. 1992). The human sperm cell membrane is particularly susceptible to oxidation due to the existence of high concentration of polyunsaturated fatty acids (PUFA) in these membranes (Tavilani H., D. Mahmoud, 2005). Physiologically, the high concentration of PUFA in sperm are integral for maintaining membrane fluidity and flexibility during fertilization process. Lipid peroxidation is known to cause impairments such as membrane damage, decrease in a chromosomal function(Aziz N., R.A. Saleh, 2004), damage to sperm chromatin and reduced sperm-oocyte fusion (Oyawoye O., G.A. Abdel, 2003; Pasqualotto E.B., A. Agarwal, 2004). Seminal plasma malondial-dehyde which is the stable lipid peroxidation product, is a simple method to evaluate the effect of lipid peroxidation on sperm (Geva E., J.B. Lessing, 1998). The presence of considerable amounts of antioxidants, e.g. vitamin C (ascorbic acid), vitamin E (tocopherol) as well as the enzymes superoxide dismutase, glutathione peroxidase and catalase have been described (Therond P., J. Auger, et al, 1996). Also, an important endogenous antioxidant in humans is the tripeptide glutathione (L ä glutamyl-L cysteinyl-glycine, GSH), which plays a central role in the defense against oxidative damage and toxins. GSH and GSH-related enzymes might play a role in sperm quality (Maarten T.M., M.J. Hennie, 2003). Ascorbic acid, a major water soluble antioxidant, acts as a major scavenger for a wide range of ROS. It is present at approximately 10 fold higher concentrations in seminal plasma compared with blood plasma, suggesting a physiological role in seminal plasma (Lewis S.E., E.S. Sterling, et al, 1997). However, it is difficult to measure the effectiveness of one antioxidant in isolation of another because there appears to be cooperation between various antioxidants. Therefore, it has been focused on the measurement of the total antioxidant status in seminal fluid. The aim of the study is to evaluate the levels of malondialdehyde, glutathione, ascorbic acid as well as total antioxidant status in seminal plasma of fertile and infertile males and the significance of any difference, if any, detected between both groups.