| Oxidative stress can cause cell senescence or death by oxidizing nucleic acid,protein,lipid and other biological molecules in the cell.In various biological systems,if too much ROS is produced,which exceeds the body’s ability to resist it,it will lead to an imbalance of the oxidation and antioxidant systems,which will trigger a state of oxidative stress and produce many adverse effects,including somatic cell senescence and gametes.Aging,early embryonic development block,etc.Oxidative stress damage is an important factor leading to early embryonic developmental retardation,so the oxidative balance within the cell is an important factor that determines the quality of later individual development.Organochlorine pesticides have their own stable properties,are not easy to decompose,and can be stored in water,soil and organisms for a long time,especially in the food chain with strong biological amplification.As an organochlorine pesticide,Methoxychlor is used worldwide to control insects and other pests.It has been used for a long time in China.Methoxychlor is still used in some areas,which has caused continuous pollution of the environment.Studies have shown that Methoxychlor can induce oxidative stress,leading to impaired mitochondrial respiration,massive production of hydrogen peroxide and DNA damage.A large part of the toxicity of methoxychlor to female reproductive function is due to the mechanism of oxidative stress,and the ovaries are the target organs of methoxychlor,but we are not clear about the effects of methoxychlor on the in vitro maturation of mammalian oocytes and early embryos.The role of.Therefore,this work aims to directly verify the hypothesis that methoxetin induces the reduction of porcine oocyte maturation and early embryonic development through oxidative stress pathway.In this experiment,the oxidative toxicity of methoxychlor was studied by detecting reactive oxygen species and mitochondrial membrane potential.The results show that methoxychlor can reduce the potential of early embryonic development,increase the level of intracellular ROS,and promote apoptosis.Experiment 1: Methoxychlor was added to the in vitro maturation medium of porcine oocytes to study its effect on the in vitro maturation of oocytes.GV stage oocytes were collected from the ovary,and after 42-44 hours of maturation and culture,the maturation rate of MII stage oocytes in the two groups were recorded.The statistical results of the spss software showed that the oocytes in the methoxetine group were added.The maturation rate of cells is significantly lower than that of the control group.At the same time,the oxidative ability of oocytes was tested,and the results showed that methoxychlor increased the level of ROS in the cell,lowered the level of GSH,and also caused mitochondrial dysfunction and reduced the level of ATP in the cell.Experiment 2: Methoxychlor was added during the in vitro culture of porcine early embryos to study its effect on the in vitro development of porcine early embryos.Through detection of reactive oxygen species,mitochondrial membrane potential,cell apoptosis,fluorescent quantitative PCR,etc.,the results showed that compared with the control group,the early embryos treated with methoxychlor significantly reduced the lysis rate,blastocyst rate,and hatching rate of blastocysts.And the total number of cells.It is worth noting that methoxychlor not only increased the level of ROS in early embryos,but also reduced the mitochondrial membrane potential.In addition,after treatment with methoxychlor,the expression of pluripotency-related genes(OCT4,NANOG,SOX2)was down-regulated and the expression of apoptosis-related genes(BAX and BCL-2)was up-regulated.The results of these data indicate that methoxychlor may reduce the early embryonic development of pigs by promoting oxidative stress.In summary,the research results indicate that methoxychlor may promote oxidative stress to cause in vitro maturation of porcine oocytes and decrease in early embryonic development. |
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