Mechanism effects of mogroside Ⅲ on the alleviation of porcine oocyte aging

【Objective】The study aimed to verify whether mogroside Ⅲ had the effects to delay the aging process of porcine oocytes in vitro and provide reference for utilizing plant extracts to alleviate oocyte aging in vitro.【Method】Porcine oocytes cultured in vitro for 44 h were used as research subjects. The effective concentration of mogroside Ⅲ for porcine oocytes was screened by parthenogenetic activation （PA）. Three treatment groups were set up：fresh oocytes （Fresh），aging oocytes（Aging），and aging oocytes supplemented with mogroside Ⅲ. Immunofluorescence staining and real-time fluorescence quantitative PCR were employed to detect mitochondrial content and distribution，adenosine triphosphate（ATP）content，mitochondrial membrane potential，reactive oxygen species（ROS）levels，DNA damage， antioxidant-related gene expression，and early apoptosis levels in porcine oocytes.【Result】Aging extremely significantly decreased the embryonic cleavage rate and blastocyst development rate of parthenogenetic activated embryos derived from porcine oocytes（P<0.01，the same below）. The addition of mogroside Ⅲ effectively improved the embryonic cleavage rate and blastocyst development rate of aging oocytes，especially at 25.0 µmol/L. which was therefore determined as the effective concentration for mogroside Ⅲ. Compared with the Fresh group，the Aging group exhibited significant decrease in mitochondrial fluorescence intensity（P<0.05，the same below），and extremely significant decrease in ATP content，significant decrease in mitochondrial membrane potential，and extremely significant decrease in the relative expression levels of antioxidant-related genes，while ROS levels，γ-H2AX fluorescence intensity，and Annexin-V positive rate were extremely significantly increased. However，the addition of 25.0 µmol/L mogroside Ⅲ effectively improved the above problems，indicating that mogroside Ⅲ could effectively alleviate the aging process of porcine oocytes.【Conclusion】Mogroside Ⅲ effectively delays the aging process of porcine oocytes by improving mitochondrial number and ATP content，restoring ROS balance，up-regulating the expression of antioxidant-related genes，and alleviating DNA damage and early apoptosis caused by the aging of porcine oocytes，thereby enhancing the in vitro developmental competence of porcine oocytes.