Effects Of Ginkgo Biloba Extract On P-Tau Protein Expression In Neonatal Rats After Hypoxia And Ischemia

Objective:Establishing hypoxic ischemic brain damage(HIBD)model in neonatal rats,to observe the expression of phospho-microtutubule-associated protein Tau(p-Tau)during the treatment of HIBD with Ginkgo biloba extract(EGB),to provide a new theoretical basis for the clinical treatment of EGB in hypoxic-ischemic encephalopathy(HIE)in neonates.Methods:Sixty newborn 7-day-old clean SD rats were randomly divided into sham operation group 20,control group(NS group)20 and EGB treatment group(EGB group)20.According to the time of execution,the animals were divided into 5 subgroups(6h,12 h,24h,48 h and 72h),with 4 animals in each subgroup.They all lived in the same cage with their mothers.In the sham operation group,the neck skin was incised and the right common carotid artery was separated without ligation.Both the NS control group and the EGB treatment group established HIBD animal models according to the Rice method,and observed the behavioral changes of newborn rats before and after the model construction.EGB group was intraperitoneally injected once a day with EGB 0.01g/g,and NS group was intraperitoneally injected once a day with normal saline 0.01g/g.Brain tissue was removed at each time point.Of brain tissue morphology observed with HE staining method,using immunohistochemical staining method and PCR method for each newborn mouse tissues p-Tau protein positive expression of strength and mRNA level.Results:1.Behavior of newborn rats after HIBD surgery: slow movement,shaking head,shaking limbs,unsteady standing,inability to turn over,even convulsion,etc.2.HE staining of brain tissue: the morphology and structure of neuronal cells in the sham group were normal,and no obvious pathological changes were observed.The brain tissues of NS group and EGB group were damaged to different degrees: the brain tissues of newborn mice showed different degrees of swelling of brain cells,disordered arrangementof nuclei,and nuclear contraction.NS group 6 h in the cell nucleus is arranged with a little disorder,as the growth of the time,visible cell swelling,12 h group organization structure is loose,visible more cavity structure with microglia infiltration,neurons,visible just a few cells and neurons pyknosis,cerebral vascular congestion,with inflammatory cells infiltration around a 72 h group of cells in the 12 h group order,cell swelling subsides.In the EGB group,the nuclear arrangement in the 6h group was slightly disordered;in the 12 h group,a small number of neurons were observed to shrink,the tissue structure was loose,and the number of cells in local areas was rare;while in the 72 h group,the cells were arranged neatly,the degree of cell swelling was reduced,and microglia cells were observed compared with the 12 h group.Compared with NS group,the morphological degree of pathological injury was reduced in EGB group.3.Immunohistochemical results:the positive staining of the cytoplasm of p-Tau protein brain nerve cells was all brown-yellow,and brown-yellow positive expression was observed in all three groups.The number of p-tau positive cells in the sham group increased at 6h and reached the peak at 12h(P<0.05),then decreased gradually at 24 h and48h(P<0.05),and at 48 h and 72h(P>0.05).The number of p-Tau positive cells in NS group increased at 6h and reached the highest point at 12h(P<0.05),and then decreased gradually at 24 h,48h and 72h(P<0.05).The number of p-Tau positive cells in EGB group began to increase at 6h and reached the peak at 12h(P<0.05),and then decreased gradually at 24 h,48h and 72h(P<0.05).The number of p-Tau positive cells in NS group was higher than that in EGB group at each time point(all P<0.05).4.q-PCR results: the relative expression of p-tau mRNA in the sham group increased at 6h and reached the peak at 12h(P<0.05),and then decreased gradually at 24 h and 48h(P<0.05),and at 48 h and 72h(P>0.05).The relative expression of P-Tau mRNA in NS group began to increase at 6h and reached the peak at 12h(P<0.05),and then decreased gradually at 24 h,48h and 72h(P<0.05).The relative expression of P-Tau mRNA in EGB group began to increase at 6h and reached the peak at 12h(P<0.05),and then decreased gradually at 24 h,48h and 72h(P<0.05).The relative expression level of P-Tau mRNA in NS group was higher than that in EGB group at each time point(all P<0.05).Conclusion:1.EGB can play a therapeutic role on posthibd newborn rats by inhibiting the expression of p-Tau protein.2.p-Tau protein is involved in the process of HIBD.3.The brain p-Tau protein of normal newborn rats and HIBD newborn rats showed dynamic changes.