Effect Of Taurine On The Hippocampal Apoptosis And Neurogenesis Of Neurons In The Hippocampus Of Rats Under Chronic Stress

Unpredictable chronics(Chronic mild unforeseeable stress,CUMS)tress can cause damage to the hippocampal neurons,accelerate neuronal cell apoptsis and further induce neurodegenerative diseases such as depression and Alzheimer.The chemical nature of taurine is stable,not only protect the nervous system,but also enhance the memory function.The aim of this study was to investigate the regulation effect of taurine on the apoptosis and neurogenesis of hippocampal neurons in rats under CUMS,and to provide a theoretical basis for the application of taurine in the prevention and treatment of neurodegenerative diseases.In this study,SPF rats were used to establish the CUMS models,and all the rats were divided into six groups:the blank control group(N),the taurine control group(T ?,T?),the chronic stress model group(M)and the taurine treatment groups(T? +M,T?+M).The weight of the rats was weighed and the sugar preference test were carried out every week.28 days later,the effects of taurine on the behavior of CUMS rats were examined by open field test and Morris water maze test.Then the hippocampus of rats were collected by cardiac perfusion fixation.The expression of Ki67 and apoptosis regulating factors were detected by immunohistochemistiy.The neuronal apoptosis was detected by TUNEL.At the same time,the expression of Caspase-3,Caspase-9,Bax and Bcl-2 mRNA and protein were detected by Real Time-PCR and Western-blotting.The results showed that with the development of chronic stress,the rats in the model group had lower preference to sucrose compared with the blank control group and the taurine treatment group,the differences was significant(p<0.01).the weight grain is slow in chronic stress group compared with the other groups;In the open field test,the exploration ability to the new environment of the rats in the model group was lower,with shorter time spent in thecentral areaand more time in the peripheral area,which was significantly different from that in the blank control group and the taurine treatement group(p<0.05);Meanwhile,the rats in the chronic stress group were more anxious with lower horizontal score and vertical score than the blank control and taurine treatment groups(P<0.01).In the Morris water maze,the rats in the model group spent a longer time and longer distance to find the platform.and less platforn crossing time,which were all significant compared with the control group and the taurine treatment groups(P<0.01 or p<0.05).Immunohistochemical results showed that the apoptotic rate of the neurons in the DG region,the positive expressions of Caspase-3?Caspase-9?Bax were all significantly higher than the blank control group and taurine treatment groups(p<0.01 or p<0.05).Whilethe positive expression of apoptosis inhibitory factor Bcl-2 was less than the blank control and taurine treatment groups(p<0.01or/p<0.05).The positive expression of Ki67 in the hoppocampus of rats in the model group was significant lower than the blank control and taurine treatment groups(p<0.01).The mRNA and protein expressions of Caspase-3,Caspase-9,Bax were significantly higher in the model group compared with the blank control and taurine treatment groups(p<0.01 or p<0.05).The mRNA and protein expressions of Bcl-2 was significant lower in the model group than the blank control and taurine treatment groups(p<0.01 or p<0.05).The results of this study indicated that taurine can inhibit the abnormal apoptosis in the hippocampus of rats induced by CUMS by regulating endogenous apototic pathway.And thus ameliorate the behavioral changes including the lack of pleasure,learning and memory capacity deficiency and increase of anxiety.