Study On Mogroside Ⅴ Alleviates The Meiotic Defect Induced By Lipopolysaccharide In Porcine Oocyte

Gram-negative bacteria infection seriously affects the reproductive performance of livestock and brings significant economic losses to livestock husbandry.The oocyte quality is related to the reproductive performance.Lipopolysaccharide(LPS),a toxic component of gram-negative bacteria,causes a decline in oocyte maturation rate and embryonic development potential.We previously found that mogroside V(MⅤ)can promote oocyte maturation and alleviate oocyte aging,which may be related to the inhibition of oxidative stress and the promotion of mitochondrial function.But whether MⅤ can alleviate the damage of oocyte maturation caused by LPS is still unclear.Therefore,porcine oocytes were used as the experimental model in this study,immunofluorescence staining and RT-q PCR techniques were used to preliminarily explore the ameliorate effects of MⅤ on LPS-exposed oocyte meiotic defects.The main findings are as follows:(1)MⅤ alleviates meiotic inhibition of LPS-exposed porcine oocytesTo investigate the alleviated effect of MⅤ on meiotic inhibition in LPS-exposed porcine oocytes,different concentrations(5,10,15μg/m L)of LPS were added into the maturation medium first.The results showed that the PBE rate decreased with the increase of LPS concentration,and 15μg/m L of LPS significantly inhibited the maturation of porcine oocytes.Then different concentrations of MⅤ(25,50,100μM)were added to the maturation medium containing 15μg/m L LPS.It was found that the PBE rate increased with the increase of the concentration of MⅤ,and the effect of 50μM MⅤ was the best.Therefore,this concentration was selected for subsequent experiments.We further observed that LPS exposure inhibited cumulus expansion,resulting abnormalities in spindle assembly and chromosome alignment,decreasedα-tubulin acetylation level and destabilized actin filaments,and MⅤ could effectively alleviate these abnormalities.These results suggest that MⅤ can effectively alleviate meiotic defects of porcine oocytes caused by LPS exposure.(2)MⅤ alleviates the quality damage of LPS-exposed porcine oocytesBesides nuclear maturation,cytoplasmic maturation also plays an important role in determining oocyte quality.So,we further explored the alleviating effect of MⅤ on the quality damage in LPS-exposed porcine oocytes.The results showed that LPS exposure did not affect the mitochondrial distribution of oocytes,but decreased the mitochondrial number and ATP content,lipid droplets number and glucose uptake capacity,indicating that oocyte metabolism is impaired.In addition,LPS exposure decreased m~6A levels,increased ROS levels,down-regulated expression of antioxidant enzymes(CAT,GPx1 and SOD1),and increased early apoptosis rates in porcine oocytes.Furthermore,LPS exposure significantly reduced the blastocyst rates after parthenogenetic activation.The addition of MⅤ in medium had significant alleviating effects on the above abnormal phenomena caused by LPS exposure,indicating that MⅤ could alleviate the damage of oocyte quality caused by LPS exposure.In summary,this study demonstrates that MⅤ can alleviate the meiosis disorder,oocyte quality damage and the decreases of embryonic developmental potential caused by LPS exposure.The reduction of ROS level in LPS-exposed oocytes by MⅤ may be a potential mechanism of action to alleviate the abnormalities.The results of this study provide a reference for using MⅤ to alleviate LPS-induced oocyte maturation damage.