The aim of this study was to evaluate the effect of alpha-lipoic acid on quantitative and qualitative of mouse embryos treated with lipopolysaccharide. For this purpose, we first studied the effective concentration of alpha-lipoic acid and lipopolysaccharide on fragmentation and blastocyst formation. The numbers of intracellular masses and trophectoderm were determined by differential staining, the mitochondrial distribution of blastocyst with Mitotracker green staining, the intracellular ROS levels in embryos, during blastocyst stages, were measured by 2?,7?-dichlorofluorescein (DCF) fluorescence assay and glutathione content indicated by cell tracker blue method. The expression of TLR-4, Nrf-2 and TNF-RI / P60 receptor in inflammatory pathways induced by the lipopolysaccharide and treated with alpha-lipoic acid was performed using the RT-PCR method. At the end, obtained embryos from experimental groups were transferred to synchronized mouse and their implantation and pregnancy rates were evaluated. The results of this study showed that the concentration of 1mg/ml of lipopolysaccharide induced free radical production (P?0.05), decreased intracellular glutathione (P?0.05), and reduced mitochondrial mass (P?0.05), then decreased the survival of mouse embryo (P?0.05). Also, this level of lipopolysaccharide increased the expression of TNF-RI/P60 receptor and Nrf-2 (P?0.05). In order to reduce the unpleasant effects of lipopolysaccharide, after determining the optimal level of 10?M alpha-lipoic acid from the tested levels (0, 1, 10 and 100 ?M), the results showed that the use of this level was able to significant reductions in the production of free radicals (P?0.05), increased glutathione content (P?0.05), improvement of mitochondrial mass (P?0.05), improved blastocyst quality (P?0.05), increased the number of ICM and TE cells (P?0.05), and finally improved the survival rate of embryos treated with lipopolysaccharide (P?0.05). Therefore, the findings of this study suggested that although using 1 mg/ml LPS could reduce the survival rate and quality of mouse embryo and reduce the implantation, adding 10 µM ALA could modulate the harmful effects of LPS on survival and implantation of embryos. Key Words Lipopolysaccharide, Alpha-lipoic acid, Embryo, Mouse, Oxidative stress
