| ?Purpose?The purpose of this paper is to investigate whether the exosomes derived from High-Expression BDNF Mesenchymal Stem Cells(H-BDNF-MSCs)in the model of middle cerebral artery occlusion(MCAO)in rat brains play a protective role against the cerebral ischemia-reperfusion injury by inhibiting neuron apoptosis.?Method?In this paper,50 male rats were selected to prepare the middle artery embolism model(MCAO)in rat brain by using Longa meth od.They were randomly divided into 5 groups,including the sham operation group,the model group,the low,medium and high dose size groups of exosomes derived from MCAO-H-BDNF-MSCs(low,medium and high dose experimental groups),each group of 10 rat s.MCAO-H-BDNF-MSCs-derived exosomes size groups were treate d with transplantation.At the point of post-ischemia 2 hours and re perfusion 24 hours,H-BDNF-MSCs-derived exosomes were treated with transplantation through the tail vein.The sham operation group and model group were given the same amount of normal saline instead.One week after the surgery,all groups were scored for neuro logical function by using Zea Longa 5-grade scale method.All gro ups were executed 2 weeks after the surgery and their brain tissue samples were taken.The infarct volume of each group was detected by 2,3,5-triphenyltetrazolium chloride(TTC)staining method.He matoxylin Eosin(HE)staining method was used to detect the histo pathological changes in the brain tissues of rats in each group.Hoe chst-33258 was used to detect the neuron apoptosis in each group.The protein expression levels of BCL-2,BAX and Caspase-3 in eac h group were detected by using Western Blot.?Result?1.It showed that compared with the sham operation group,Compared with the model group,the neurological function score was decreased in the medium and high-dose experimental groups(P<0.05).2.The results of TTC staining showed that compared with the sham operation group,the model group caused obvious ischemia infarction in the brain tissues of rats.Compared with the model group,the infarct volume of the medium and high dose experimental groups decreased(P <0.05).There was no statistical difference between the low dose experimental group and the model group(P> 0.05).3.The results of HE staining showed that the model group the cell shapes in the infarction area was abnormal with reduced volume,and the cell nucleus appeared to shrink and lyse with irregular cell alignment.Some cells in the experimental group have abnormal shapes and reduced volume.However,compared with the model group,the experimental group has more complete cell shapes.4.The results of neuron apoptosis tested by Hoechst-33258 staining in each group showed that compared with the sham operation group,the positive cell rate of the Hoechst-treated neutrons in the model was significantly increased(P <0.001).Compared with neurons in the model group,the positive cell rate of the Hoechst-treated neutrons in the medium doze experimental group was significantly reduced(P <0.05).Compared with neurons in the model group,the positive cell rate of the Hoechst-treated neutrons in the high doze experimental group was significantly reduced(P <0.01).There was no significant difference on the positive cells of the Hoechst-treated neutrons between the low dose experimental group and model group(P > 0.05).5.The results from the test of Western blot showed that:(1)Compared with the sham operation group,the relative protein expression levels of BAX and Caspase-3 of the brain tissues in rat in the model group were significantly increased(P <0.001).The protein expression level of BCL-2 was significantly down-regulated(P <0.001).(2)Compared with the model group,the protein expression levels of BAX and Caspase-3 of the brain tissues in high dose experimental group were significantly down-regulated,and the BCL-2 protein expression was significantly up-regulated(both P <0.001).Compared with the model group,the protein expression levels of BAX and Caspase-3 of the brain tissues in the medium dose experimental group were down-regulated.The protein expression level of BCL-2 was significantly up-regulated(both P <0.01).Compared with the model group,the protein expression levels of BAX and Caspase-3 of the brain tissues in low dose experimental group decreased relatively,and the BCL-2 protein expression level increased relatively.There was no statistically significant difference in the degree of decrease and increase in their expression levels(all P> 0.05).?Conclusion?1.The exosomes derived from H-BDNF-MSCs can inhibit neurons apoptosis in Cerebral Ischemia-Reperfusion Injury2.The exosomes derived from H-BDNF-MSCs may play a protective role against rat brain ischemia-reperfusion injury by regulating apoptosis factors,and the effects appear good in a size group of 100 ug dose. |
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