The Study Of D2and D3Expression Profiles In Central Nervous System Of Neonatal Rats With Hypoxic-ischemic Brain Damage

ObjectiveToobserve the changes of type2iodothyronine deiodinase(2and type3indothyronine deiodinase(3) mRNA express profiles of cerebrum,cerebellum,hypothalamus,medulla and spinal cord in hypoxic-ischemic brain damage(HIBD) neebom rats,explore potenial mechenisms of newborn rats with HBD and ESS, and to provide toredcal fixmdalicn fer the treatment of hypoxic-ischemic enephalopathy(HIE) and euthyroid sick syndrome(ESS). Metod1.Establishmenr ofHIBD model:Neonatal7-day-old Wistar rats were randomly divided into control group,HIBD0h,6h,24h,48h,72h and96h groups,sham-operation0h,6h,24h,48h,72h and96h groups. The model of HIBD was induced by unilateral carotid of HIBS groups ligated followed by2h exposure to8%oxygen Left common carotid atery ligations of sham-operation control groups rats were separated.All the were executed at corresponding time after the process.2.General examination of the brain:Contrasted the appearance after execution.3.Expression profiles of D2and D3A mRNA in cerebrum,cerebellum,hypothalamus,medulla and spinal aord was measured by Real-time PCR metod. Results1.Behavior of all neonatal rats normal before operation.After hypoxia the rets od(HIBD) group showed behavior problem2.General examination of the brain:The two brain hemigtees of sham goips showed no pathological change. The ligated eofHBD groups showed obvious pallor, edema and liquefactive necrosis lesion.3.Expression profiles ofD2mRNA in the cerebellum,hypothalamus,medulla and spinal cord:3.1D2mRNA can be detected in cerebrum,cerebellum,hypothalamus,medulla and spinal cord od neonatal ratsl;D2mRNA in cerebrum was much higher than the others;after hypoxia D2mRNA in cerebrum was the highest too;the differences were ststistically signficant;32D2mRNA levels of cerebium of neonatal rate increased fiom7to11days after delivery,D2mRNA levels of cerebellum, hypothalamus and medulla increased and then decreased;the changes ofD2mRNA levels of spinal cord were not statistically significant, after hypoxia, D2mRNA levels of cerebrum increased and to decreased and then increased, D2mRNA levels of cerebellum, hypothalamus and medulla increased rapidly and then going up and down alternately but were always higher than the levels of sham groups,increaseofD2mRNA levels of spinal cord begins at24h after hypaxia;33Standardized by D2mRNA levels of normal neonatal rats different time,D2mRNA levels ofHIBD groups of cerebrum went down and then up, the ones of cerebellum, hypothalamus and medulla went up immediately and then back down,the changes of D2mRNA levels of spinal cord were not statistically significant; 3.4Hypoxia influenced D2mRNA levels of different pats of of central nervous system(CNS) differently: D2mRNA levels of cerebrum ofHBD groups wae all lower than sham groups; the levels of cerebellum of HIBD groups were all higher than sham groups except for72h group;the levels of hypothalamus and medulla went up and then down;the levels of spinal cord went up24h,48h,72h, and96h after hypoxia.4.Expression profiles of D3mRNA in the cerebrum,cerebellum,hypothalamus,medulla and spinal cord:4.1D3mRNA can be detected in cerebllum, hypothalamus,medulla and spinal cord of neonatal rats;D3mRNA in cerebrum and spinal cord was much higher than others;after hypoxia D3mRNA in hypothalamus and medulla decrease and the ones in spinal cord increased;42D3mRNA levels of cerebrum and cerebelum of neonatal rate increased and then flattened out after delivery, the levels of hypothalamus and medulla increased and then deceased; the changes of D3mRNA levels of spinal cord were not statistically significant except for the slight elevation7to8days after hypoxia,D3mRNA levels of cerebrum increased immediately and then decreased, D3mRNA levels of cerebellum, and spinal cord increased immediately and the levels of spinal cord reachedapeak at96h after hypoxia;43Standardized by D3mRNA levels of normal neonatal rats at different time, D3mRNA levels of HBD groups of cerebrum cerebellum, hypothalamus and medulla went up swiftly and then went dowr,the rise od spinal cord were not statistically significanr except for96h after hypoxia;4.4Hypoxia influenced D3mRNA levels of different parts of CNS fifferently:D3mRNA levels of cerebrum,cerebellum and hypothalamus increased and ten decreased; the levels ofmedulla ofHBD groups were lower than sham groups;the levels of spoinal cord of HBD groups were higher than sham groups. Comclusions1. The HIBD model was succeddfully established2. D2and D3mRNA can be detected in cerebrum, cerebellum, hypothalarnus, medulla and spinal cod of neonatal rats; the exrxession profiles and effects ofHBD were temporal specific and spatial specific.3. HIBD decreased the expression ofD2mRNA and increased the expession ofD3mRNA of cerebrum of newbom rats, not only deaeasd the activition but also increased the inactivition of thyroid homone(TH),which may contribute top the onset ofESS4.After HIBD of neonatal rats,TH level was supposed to retum to normal.