Preimplantation Genetic Diagnosis Was Performed To Evaluate Glucose Metabolism In Newborn Mice

Since the preimplantation genetic diagnosis(PGD)was firstly proposed in 1990 by Handyside and copartners,PGD have been widely used all over the world.The processes of PGD involves in a range of manipulates,including controlled ovarian stimulation,in vitro culture,embryo transfer and blastomere biopsy.However,these non-natural and/or invasive manipulates which different from normal physiologic act on critical window of gametogenesis and early embryonic development.Adverse influences on the development of its offspring have not been evaluated systematically before PGD is widely used in clinic.With the theory "embryo-fetal origin of diseases" gradually being acknowledged,it is necessary to evaluate the health of PGD offsprings.We construct mouse model to the research.The PGD mice as the experimental group(one blastomere was removed was removed randomly from each in vitro fertilezed four-cell embryo,biopsied three-cell embryos were transferred into the pseudopregant mice,the birth offsprings are PGD mice),TVEM mice(in vitro fertilezed four-cell embryo without biopsiy,then transferred into the pseudopregant mice,the birth offsprings are IVEM mice)and Normal mice(mice of natural mating and delivery)as control groups.We evaluate the status of the glucose metabolism of three groups of mice,attempting to reveal whether there is potential high risk of diabetes(potential chronic metabolic disease),and preliminarily explor the possible mechanism.Firstly,we detected blood glucose parameters of mices in three groups,including blood glucose and serum insulin collected from introperitoneal glucose tolerance test(IPGTT),to reflect abnormal regulation of glucose metabolism.The results show that the fasting blood glucose level of PGD and IVEM mice were higher than Normal mice,but there is no statistical differences between IVEM and Normal mice.Glucose levels were not different at 15min,30min,60min and 120min after intraperitoneal injection of glucose among the three groups.,and blood glucose levels can drop to fasting levels each group of mice at 120 min postinjection.The results suggest that blood glucose regulation of PGD mice may be affected.In order to explore whether the differences of the fasting blood glucose level due to abnormal function of pancreatic secretion,we have tested the serum insulin and glucagon level of three groups of mice.There are no differences in the fasting insulin levels of three groups of mice,but insulin levels of PGD and IVEM mice are higher than Normal mice after intraperitoneal injection of glucose,and PGD and Normal group are statistically difference,especially at 15min?60min and 120min postinjection.However,there are no significant differences between the PGD and IVEM groups.In addition,there is no difference among three groups of mice serum glucagon.So secretion capacity of islet seems to be no obvious problem in PGD and IVEM mice.In order to further explore the cause of the elevated blood glucose level,we have studied the structure and functionin of liver,skeletal muscle and pancreas,which are the organs involved in glucose metabolism.The morphological analysis shows no significant differences in structure of the three organs among three groups of mice.Then,we analyzed function of liver and skeletal muscle.Because the glucose in the blood can be transported into hepatocyte and myameba by glucose transporter,and turn into glycogen by glycogenesis,we have detected glycogen content to reflect glycogen reserve.The content of hepatic glycogen of PGD and IVEM mice are found to be lower than those of Normal mice.What's more,we have researched capacity of gluconeogenesis,glycogenolysis and glycolysis in liver by detecting activity of key enzyme in glycometabolism.The results show that the activity of glycogen synthase(GS),citrate synthase(CS),and alpha-ketone glutarate dehydrogenase(a-KGDH)in PGD mice is lower than those of Normal mice.The above results suggest that PGD manipulates may lead ability of glycogenesis and glycolysis in offspring liver to decline,which may be the reason why blood glucose of PGD mice rise.For mechanism of the embryonic origin disease,epigenetic modification has been cognized so far.Impringting gene methylation modification is a hotspot of current research.So we also choose the more classic imprinting genes(Igf2.H19?Mest)to explore the mechanism of PGD progeny sugar metabolic abnormalities.The results showed that methylation of H1 9 DMR,Igf2 DMR2 and Mest DMR did not differ among three groups.However,the mRNA relative expression of H1 9 in PGD and IVEM group were obviously lower than that of Normal group.Results suggest expression of imprinting genes may be regulated by multiple epigenetic modifications,but the specific mechanism remains to be seen.In conclusion,elevated fasting glucose and key enzyme activity change in glucose metabolism in mice born of PGD may be liver dysplasia,which cause abnormal glucose metabolism and blood glucose rise.That suggest PGD has the potential risk to cause the diabetes.IVEM mice although have the tendency of elevated blood sugar,and enzyme activity change,but there is no statistical difference.To determine whether blastomere biopsy operation,the unique operation of PGD,will affect the PGD offspring glycometabolism,and the potential mechanism still need to further study.