Neurological Development Evaluation Of Blastocyst Biopsy Mice By Preimplantation Genetic Diagnosis Technique

Preimplantation genetic diagnosis(PGD)is commonly used in clinical assisted reproductive technology to analyze the genetic material of embryos before implantation even oocytes so that abnormal embryos can be eliminated.Using this effective prenatal diagnosis method,certain genetic diseases can be detected and termination of pregnancy can be avoided meanwhile the newborn will be free from suffering genetic diseases.PGD can be divided into polar body biopsy,blastomere biopsy and blastocyst biopsy.The polar body biopsy requires the first and second polar body which will cause penetration twice and only genetic information from mother can be analyzed.The blastomere biopsy is performed at cleavage stage cause long-term effects on growth and post-natal behavior and genetic abnormal.Although the blastocyst biopsy has been widely used clinically,the safety of this technique hasn’t been evaluated systematically since its invention and infants born with this technique also lacked of long term health track.To evaluate the long-term effect of blastocyst biopsy on subjects,ICR mouse were used as experimental animals.The mouse offsprings that had undergone blastocyst biopsy were group PGD,compared with control which were natural delivered.Early research showed ZP and PGD is safe in early growth.To evaluate the long-term effects of the behavior,we aimed to assess the influence of the technique on psychiatric diseases,including anxiety,depression.We performed behavioral analysis including tail suspension,open field,elevated plus maze,sucrose preference on group PGD and control.Also,weight change of internal organs were collected.Immunohistochemistry and qRT-PCR were performed using brain tissue to detect expression different in several brain injury marker gene.Previous experiments showed no significant different in embryo development between group PGD and control after segmentation of zona pellucida and blastocyst biopsy.Post-natal development was normal in previously study.Behavior experiment including Tail suspension test,Sucrose preference test,The elevated plus maze,The open field test show no psychiatric like symptom in group PGD.Between group PGD and control,in OPT,average speed(0.088±0.004 cm/s vs 0.093±0.008 cm/s),total moving distance(69.950±4.819 cm vs 79.532±9.285 cm),time at walls(433.575±10.860 s vs 403.908±13.001 s),time in the corner(319.300±17.363 s vs 279.481±30.030 s),time in the out-ring(745.746±13.511 s vs 661.183±57.100 s),moving distance in the out-ring(53.290±2.847 cm vs 51.921±6.632 cm),moving distance in the central(20.510±1.216 cm vs 22.891±2.387 cm)and time in the central(152.588±17.903 s vs 208.000±37.011 s),no significant different was shown(P>0.05).in the EPM,time in open arms(28.01% vs 25.01%),time in close arms(44.94% vs 48.52%),times enter open arms(63.85% vs 58.08%)and times enter close arms(36.15% vs 41.92%),no significant different was found.Immunohistochemistry,Western Blot and qRT-PCR results show Mbp,Prdx5,Uchl1 remain unchanged while Snap-α expression decreased.In conclusion,from the perspective of neurodevelopment,the safety of blastocyst biopsy is significantly better than blastomere biopsy.No abnormality was found in natural neurobehavioral ability and induced neurobehavioral ability in aged blastocysts biopsied mice.The cause and effect of the decrease in the expression of Snap-α in PGD mice need further study.