Study On Superovulation And Early Embryo Development In Vitro In Dog

In the modern life,dog make a great improvement to the humans'health and families'harmony,as well as improve the quality of life.Also,it has made huge contribution to disease search.Along with the rapid development of canine assisted reproductive technology and gene editing technology,dogs are also meaningful to be used as animal models of human diseases research,such as breast cancer,Alzheimer's disease and Parkinson's disease.Due to the importantce of dogs,the use of assisted reproductive technology to improve or even enhance the dog's body function and contribution ability,which has become a key part of the dog research.From the special reproductive physiological characteristics of dogs,the estrous cycle and ovulation time of dogs have a large difference from other animals,which makes the assisted reproductive technology still imperfect.Therefore,this paper base on the physiological characteristics of dogs,explore the development of early embryos in dogs,and further enhance the dog assisted reproductive technology by the means of exogenous reproductive hormones to superovulation in dogs with different reproductive status.Experiment one:Exploring the superovulation scheme of dogs with different reproductive status.With health,genital structure and normal function,20 Chinese rural dogs in different reproductive status were used as experimental animals.By three reproductive hormones eCG,hCG and PGF2?,the superovulation experiment was performed in dogs with different reproductive status.These dogs were divided into 5groups,four groups were for superovulation,and one group as control,each group has 4dogs.I?II?III group are 1.5-2.5 years old dogs.Group I was anestrus dogs with regimen of one time of eC G 200 IU/day,for 17 days;then hCG 500 IU,one time;Group II was metaestrus dogs with regimen of one time of eCG 200 IU/day,for 11 days;then hCG 500IU,one time;Group III was dioestrus dogs with regimen of 4 times of 0.3 mg of PGF2?/day,for 3 days;after that one time of eCG 200 IU/day,for 19 days,then hCG 500IU,one time;Group IV was 8-12 months old young dogs with regimen of one time of eCG200 IU/day,for 11days;then hCG 500 IU,one time;Group V was 1.5-2.5 years old oestrus dogs,without any treatment.The results showed that:all experiment dogs in the experimental group I,II,III were successfully induced estrus?100%?,and the induced estrus rate of experimental group IV is 75%.The average number of ovulation in group I was 27.25±2.06,the average number of ovulation in group II was 33±3.46,the average number of ovulation in group III was 24.67±1.53,the average number of ovulation in group IV was 11.33±3.21.The experimental group I,II,III,IV had higher the average number of ovulation than the control group was 10.33±1.53.The ovulation number difference between the group I,II,III after Superovulation and the control group was significantly?P<0.01?,after Superovulation,the ovulation number of group IV had no significant difference from the control group of natural estrus ovulation?P>0.05?.By followed the characteristics of reproductive physiology index in the experiment,the results showed that:the maintenance of dogs increased in the progesterone level,estradiol level increased in the platform period.The specific situation was expressed that the vulca of female sample became soft,not swollen but returned to normal folds with genital mucosa color of weak powder and even partial white.Vaginal epithelial cell smear keratinocytes in about 90%,when a large number of follicles in the mature stage before ovulation.Experiment two:A preliminary study on the development of early canine embryos in vitro.With the normal estrous and successfully received dogs mating female canine as experimental animals,the surgery embryo flushing method was used to obtain 2-4 cell embryos on the fourth day after the mating of experimental animals.The embryos were treated with 4 different cell culture media?TCM199,M2,M16,SOFaa?at 38.5?,5%CO₂,100%humidity in the incubator.The results showed that the embryos could not develop in the medium of TCM199,M2 and M16.In the SOFaa medium,the embryos could grow to the morula stage.In order to explore the status of early embryonic development,2-4 cell embryos in SOFaa were cultured on 37.5?,38.0?,38.5?,39.0?and 39.5?culture in the incubator,the results showed that the early embryos can develop to morula stage contraction at 38.5?.Totally,using exogenous reproductive hormones eCG,hCG and PGF2?could successfully induce different estrous stage of dog estrus and ovulation,and the oocytes collected more than natural estrus.Under the conditions of 38.5?,5%CO2 and 100%humidity,the SOFaa medium could be used for the early embryos culture in vitro.