Effects Of Different Intensity Treadmill Exercise On Learning And Memory Function In Rats And The Regulatory Mechanism Of MicroRNA-483 And IGF2

Intent:To study the effect of different intensity tread training on learning and memory.To investigate the expression and regulatory mechanism of micro RNA-483 and IGF2 in treadmill exercise.So,this paper describes the purpose of the study through three parts.First: tread training to improve learning and memory abilityMethod: 32 male SD rats of 2 month old were randomly divided into 4 groups: Control group?normal eating,no exercise training?;Slight intensity?18m/min x 30min?;Moderate intensity?24m/min x 30min?;Hight intensity?30m/min x 30min?.In order to find the learning and memory ability of the rats,we carry out the test of Morris Water maze after 6 weeks.Result: After 4 days of directional navigation,the escape latency of the tread training group was significantly shorter than that of the control group.In the first day of the directional navigation,the moderate intensity group of the treadmill training group was significantly shorter than that of the control group,has significant differences?P<0.05?.Space exploration of 1 day,we find that the number of tread training groups increased significantly compared with the control group in frequency of passing tread,but the overall difference was not significant.But in percentage of the distance,the moderate intensity group was significantly lower than that in the control group?p<0.05?.There was no significant difference between the other groups?P>0.05?.Conclusion: Tread training can improve cognitive function,Moderate intensity group effect is more significant.Second: gene chip screening.Methods: First,We crossed the four groups of genes through Venny,to find out four groups of common genes.We then made a trend graph of four groups of genes through Me V,expression of each group of different genes intuitively.This experiment is a cognitive function study,we crossed the GO-memory functional genes in the four groups of gene chips,and to target our genes by up-regulating or down-regulation of the genes with the largest difference,and then through bioinformatics analysis,use Target Scan₇.1,mi RDB,micro RNA.org to predict.Using the pubmed database literature to determine the final target gene and regulatory mechanisms.Finally,the target gene and its regulatory mechanism were verified by QPCR,WB,IF?tissue,cell?.Results: There were 587 upregulated expressed genes and 604 downregulated expressed genes.Among upregulated genes,there were 6 genes associated with memory.Among downregulated genes,there were 4 genes associated with memory.We found IGF2,an upregulated gene,and Htr7,a downregulated genes could be regarded as vital genes through their fold change.By searching literature,we found that IGF2 was associated with memory.But,study about its role in memory of rats treated with treadmill running was few reported.Therefore,we chose IGF for further study.To better find the regulative mechanism associated with improved memory by treadmill running,we found that 69 micro RNAs could regulate IGF2 through Target Scan₇.1,mi RDB and micro RNA.org.And micro RNA-483 and micro RNA665 were both revealed in Target Scan₇.1 and mi RDB.Then,by searching literature,we chose micro RNA-483 and IGF2 as our study.And we supposed that treadmill running improved memory through the regulative role of micro RNA-483 on IGF2.The results of q-PCR showed that compwered to control group,treadmill running could increase the relative m RNA expression of IGF2,and the relative m RNA expression of IGF2 in moderate strength of treadmill running group was highest compwered with control group?P<0.05?and low strength of treadmill running group?P<0.05?.While,compwered to control group,treadmill running could decrease the relative expression of micro RNA483.Moreover,the relative protein expression of IGF2 in treadmill running groups were both increased,especially in moderate strength of treadmill running group.Immunofluorescence staining showed that IGF2 was expressed in hippocampal neuron.Conclusion: Treadmill running altered various genes associated with memory.Among them,the changes of IGF2 and micro RNA483 might be the key factors in improving memory.Third: effects of IGF2 and microRNA-483 on hippocampal neuronsMethods: The interfered fragments of IGF2 were screened after hippocampal neurons cultured in vitro.The hippocampal neurons were divided into 8 groups: Normal group?Reagent group?IGF2 normal?IGF2-NC?group,si IGF2 group?mimic negative control CY3?mi-NC??inhitibor negative control?in-NC?group,micro RNA-483 inhitibor?in-483?group?micro RNA-483 mimic?mi-483?group.Each group had 3 wells and conducted intervention except the normal group.Survival and structure of neurons in normal group were observed.Results: The effective fragments were screened in PC12 cell and Si-IGF2 wasconsidered as the most effective in the role of interfering.Under the inverted microscope,it was found that normal hippocampal neurons began to adhere to the wall and had a small protrusion at 8 hours.After 1 day,all cells could adhere to the wall.And 7 days later,the neurons were full in shape and neuritis grew into crossed net.3days after IGF2 and micro RNA-483 were transfected successfully,the number of neurons in these two groups was significantly lower than that in other groups?P<0.05,P<0.01?.However,the difference in INFsi group and mi-RNA 483 group was not statistically significant?P>0.05?.Conclusion: The survival of hippocampal neurons could be promoted by IGF2 but inhibited by micro RNA-483,which demonstrated that there might be a negative relationship between them.Therefore,moderate treadmill exercise promoted neurons to survive through up-regulation of IGF2 and down-regulation of micro RNA-483 and further improved the learning and memory function.