Influence Of Heat Stress On The Sperm Quality And Early Embryonic Development Of Mouse And The Alleviation Effect Of The Melatonin

Heat stress adversely impact the livestock industry and has caused heavy economiclosses.Its adersely impact is reflected in several aspects,including the apoptosis of thespermatogenic cell,the decreasement of the fertilization rate,the retardation of the embryodevelopment and even the resultant of sterilization of the male livestock.Subjected to theunaccuracy experimental condition in the heat stess study in the farm,most of the reseachesnow are used mouse and rats instead of livestock.But there are also some questions aboutthese reseaches because almost all of them use the same methods to make the heatstressmodle:only one or two instant high temperature are employed in the experiment to heatstress part of the animal body in a short time.The question is that the experiment conditionsis far from the real enviroment in the farm.We need a more advanced experiment modle toimitate the real heat stress condition in the farm,than we would got more meaningfulrusults to help us resolve the practical problems in the livestock industry.Melatonin is synthesized in the pineal gland as a Indoles hormone and many reseacheshave proved its high antioxidant activity.Not only itself is a oxidant scavenger,Melatoninalso can stimulates the activity of some antioxidant enzymes including catalase(CAT) andSOD.There are no definite conclusion an present that if melatonin would alleviate theadverse effect of the heat stress on the sperm quality and the early development of theembryo.In our experiment we used the artificial climate chamber to imitate the summertemperature of Beijing and we use two different temperatures to heatstess the whole bodyof the male mouse in a long-lasting period.During the heatstress,10mg/kg melatonin wasadministed by intraperitoneal injection everyday around10:30am. We examine the spermquality and the embryo developmentIn at different timepoint of the experiment to testifythe adverse effect of the heatstress and the alleviation effect of melatonin.Not only heat stress would influence the early development of the mouse by changingthe internal evironment of the oviduct and uterus,but also the heat stress would directlyinfluence the embryo itself. There are no definite conclusion an present that if melatoninwould alleviate the adverse effect of the heat stress on the in vitro development of theembryo.In our experiment two diffent concentration of melatonin(10-7M/10-9M) wereadditioned into the embryo culture solution and then we examined the embryodevelopment after the embryo were cultured in41℃for2h to testify the alleviation effect of melatonin.The result of our reseach indicates that:The more severe heat stress with the highest temperature37.3℃sifnificantly reduce thequality of the sperm and have advers effect on the development of the embryo.After theheat stess,more embryo undergoes fragment.The heat stress with the highest temperature35.6℃have an adverse effect on thedensity and membrane integrity of the sperm.It also increased the apoptosis cell number inthe mouse blastocyst.The administration of melatonin significantly incereases the qualityof the sperm which have been heatstressed.Heatstress significantly impairs the in vitro embryo development to the blastocyst andthe additon of the melatonin to the culture solution didn’t alleviate the adverse effect of theheat stress.