Empirical Study On The Expression Of TrKB And TrKB MRNA In The Cerebral Cortex And Hippocampus In The Kernicterus Model

Objective To investigate the expression of TrKB and TrKBmRNA in the region of cerebral cortex and hippocampus and explore the possible value of TrKB in bilirubin encephalopathy model by establishing the kemicterus model.Methods Sixty experimental animals were divided into six groups randomly:control group(C4h,C8h);100μg/g group(T₁4h,T₁8h),200μg/g group(T₂4h,T₂8h).Every group included 10 animals which were 2—5 days old.The bilirubin encephalopathy models were made by the way of peritoneal injection of bilirubin.All the guinea pigs were executed in corresponding time point after the injection,then,their brain tissues were fixed,at last,they were made into paraffin sections,then,treated with immunohistochemistry and in situ hybridization techniques.The cell count and the average grey level of positive-expression neuron cells were measured under the image analytical apparatus.The data were processed with SPSS11.5 statistical method.Results(1)There were some expression of TrKB and TrK.BmRNA in the cerebral cortex and hippocampus region both in control groups and experimental groups.(2) Comparing with the control groups,the expression of TrKB and TrKBmRNA of experimental groups increased.In the cerebral cortex,the expression of group T₁8h were higher than that of group T₁4h(P＜0.05),the expression of group T₂8h were higher than that of group T₂4h(P＜0.05),the expression of group T₂8h were the highest of all(P＜0.01).In the hippocampus,the increasing levels of three regions were different.Conclusions(1)The TrKB and TrKB mRNA positive-expression neuron cells were both observed in the cerebral cortex and hippocampus region of the normal neogenesis guinea pig.The quantity of TrKB and TrKB mRNA and the respond to the bilirubin were not identical in different region of hippocampus.TrKB played essential roles in proliferation,differentiation and survival of neurons during development.(2) In the region of cerebral cortex,The expression of TrKB and TrKBmRNA increased when the injury delayed and aggravated;there may be a kind of time-dose-dependedrelation.In the hippocampus,The expression of TrKB and TrKBmRNA also increased,but in the region of hippocampus,this relation was not significant.(3)There were different response sensibility and degree in region of cerebral cortex and hippocampus.The response to the injury in region of cerebral cortex may be earlier than that of in hippocampus.(4)The increasing expression of TrKB and TrKBmRNA in the cerebral cortex and hippocampus manifested that TrKB may play a important role in the repair of nerve injury induced by bilirubin,and also shown that the nerve cell need more BDNF to combine with TrK.B,and then produced a marked protection effect.