Reduced fertility is an important economic problem. One of the most important causes is infections that caused by pathogens. The presence of Gram-negative bacteria, such as Escherichia coli and endotoxins derived from them, such as lipopolysaccharide (LPS), is common in males and females. LPS is an important factor in reducing sperm quality and consequently fertility. To mitigate the harmful effects of LPS in fertility, many efforts, such as the use of antibiotics and antioxidants, have been considered. One of these antioxidants is alpha-lipoic acid (ALA), which is known to be an antioxidant and anti-inflammatory factor. The aim of this study was to investigate the effect of ALA on the quality of LPS-treated sperms and resultant embryonic development in vitro . The sperm samples were obtained from NMRI male mouse. In order to find effective doses of LPS (0.00, 0.01, 0.10, 1.00 ?g/ml) and ALA (0.00, 0.01, 0.02, 0.04 mM), dose and time dependent experiments for 0, 1, 2, 3, 4 and 5 hours were conducted. The results of dose and time response expriments showed that 0.01 ?g/ml of LPS after 4 hours significantly reduced the quality of sperm, decreased motility and survival, increased production of active oxygen species (ROS) and DNA damage in the sperm. Also, LPS had a negative effect on fertilization and developmental competence embryos produced from LPS-treated sperm (P 0.05). Our data showed that the use of ALA can eliminate the negative effects of LPS on sperms such that the concentration of 0.04 mM ALA increased motility and viability of sperms and decreased ROS production and DNA damage in LPS-treated sperm (P 0.05). ALA significantly increased the fertilization rate, growth and developmental competence of embryos production from LPS- treated sperm. Generally, LPS reduced sperm quality, fertilization rate, and consequent developmental competence of embryos (P 0.05). ALA abrogated the negative effects of LPS on sperm and increased sperm quality. Keywords: Sub fertility, Gram-negative bacteria, mouse sperm, lipopolysaccharide, alpha-lipoic acid, developmental competence
