A Preliminary Study Of MiRNA-124 Expression And Relationship With Caspase-3 After Cerebral Ischemia In Rats

Objective:This study establishes a cerebral ischemia injury model by adopting the rat middle cerebral artery occlusion (MCAO), researching the changes of miRNA-124 in brain and blood, and the relationship between miRNA-124 and Caspase-3 in brain, in order to investigate whether the miRNA-124 in blood is likely to be an early diagnosis biomarker of cerebral ischemia, and whether there is a correlation between miRNA-124 and Caspase-3 in brain.Methods:40 healthy adult male SD rats were randomly divided into 5 groups:sham group(n=8), cerebral ischemia 3 hours group(n=8),cerebral ischemia 6 hours group(n=8),cerebral ischemia 12 hours group(n=8),cerebral ischemia 24 hours group(n=8). All cerebral ischemia groups make use of the line bolt to establish the MCAO model. The Sham group were completed with all the procedure but pulled out immediately after inserting the line bolt. Using the Zea Longa score to judge whether the model was successful, and using the mNSS score to evaluate neural function. Taking whole brain with TTC staining to observe morphological changes of ischemia brain tissue and determine the position of cerebral ischemia. The real-time PCR was used to detect the expression of miRNA-124 in brain and blood, the Western Blot was used to detect the expression of Caspase-3 in brain. Finally, data were analyzed by using statistical methods.Result:Model was established successfully 15 cases,3 cases in each group. mNSS score shows:the mNSS score of every ischemia group were higher than sham group, which shows the difference was statistically significant; the mNSS score of cerebral ischemia 6 hours group was higher than cerebral ischemia 3 hours group, the mNSS score of cerebral ischemia 12 hours group was higher than cerebral ischemia 6 hours group, the mNSS score of cerebral ischemia 24 hours group was higher than cerebral ischemia 12 hours group, which shows the difference was statistically significant; with the extension of cerebral ischemia time, mNSS score gradually increased, which shows the difference was statistically significant. TTC staining shows:sham group appeared no infarction, cerebral ischemia groups appeared infarction obviously. The expression of miRNA-124 in brain:miRNA-124 was expressed in sham group and every cerebral ischemia group; the expression of miRNA-124 in cerebral ischemia 3 hours group was higher than sham group, which shows the difference was not statistically significant; the expression of miRNA-124 in cerebral ischemia 6、12、24 hours group were higher than sham group, which shows the difference was statistically significant; the expression of miRNA-124 in cerebral ischemia 6 hours group was higher than cerebral ischemia 3 hours group, the expression of miRNA-124 in cerebral ischemia 12 hours group was higher than cerebral ischemia 6 hours group, the expression of miRNA-124 in cerebral ischemia 24 hours group was higher than cerebral ischemia 12 hours group, which shows the difference was statistically significant; the miRNA-124 was up-regulated in cerebral ischemia after 6、12、24 hours, and the trend was increased gradually, which shows the difference was statistically significant. The expression of miRNA-124 in blood:miRNA-124 was expressed in sham group and every cerebral ischemia group; the expression of miRNA-124 in cerebral ischemia 3、6、12、24 hours group were higher than sham group, which shows the difference was statistically significant; the expression of miRNA-124 in cerebral ischemia 6 hours group was higher than cerebral ischemia 3 hours group, the expression of miRNA-124 in cerebral ischemia 12 hours group was higher than cerebral ischemia 6 hours group, the expression of miRNA-124 in cerebral ischemia 24 hours group was higher than cerebral ischemia 12 hours group, which shows the difference was statistically significant; the miRNA-124 was up-regulated in cerebral ischemia after 3、 6、12、24 hours, and the trend was increased gradually, which shows the difference was statistically significant.The expression of Caspase-3 in brain:caspase-3 was expressed in sham group and every cerebral ischemia group; the expression of Caspase-3 in cerebral ischemia 12 hours group was higher than sham group, which shows the difference was not statistically significant; the expression of Caspase-3 in cerebral ischemia 3、6、24 hours group was higher than sham group, which shows the difference was statistically significant; the expression of Caspase-3 in cerebral ischemia 6 hours group was higher than cerebral ischemia 3 hours group, the expression of Caspase-3 in cerebral ischemia 12 hours group was higher than cerebral ischemia 6 hours group, the expression of Caspase-3 in cerebral ischemia 24 hours group was higher than cerebral ischemia 12 hours group, which shows the difference was statistically significant; the caspase-3 was up-regulated in cerebral ischemia after 3、6、12、24 hours, and the trend was increased gradually, which shows the difference was statistically significant. The expression of miRNA-124 with the expression of caspase-3 in brain showed a significant positive correlation, which shows the difference was statistically significant.Conclusion:1. The expression of miRNA-124 in brain and blood were up-regulated after cerebral ischemia.2. The expression of Caspase-3 in brain was up-regulated after cerebral ischemia.3. The miRNA-124 in blood can be a early diagnostic biomarker of cerebral ischemia.4. The miRNA-124 was significantly positively correlated with the Caspase-3 in brain, the caspase-3 may be regulated by the miRNA-124, we can inhibit the apoptosis of neuron by intervening miRNA-124, and thus effectively prevent ischemia brain injury.