Moderate Exercise Combined With Enriched Environment Enhances Learning And Memory Through Frontal Lobe BDNF/TrkB Signaling Pathway In Rats

Background:Learning and memory is one of the higher functions of brain and an important index to measure intelligence development.Brain-derived neurotrophic factor(BDNF)/tyrosine kinase B(TrkB)is a very important signaling pathway for learning and memory.It plays an important role in the growth,survival and differentiation of neurons,and maintains the normal function of neurons and synaptic plasticity,thus maintaining the normal function of the central nervous system.Studies have found that exercise and enriched environment have significant effects on learning and memory and the BDNF/TrkB signaling pathway in rats.Compared with single intervention,multi-means combined intervention is effective in improving learning and memory in rats,but there is still a lack of comprehensive scientific evidence to support this view,and the potential molecular mechanism remains unclear.Objective:To explore the effects of 8-week treadmill exercise(TE),enriched environment(EE),treadmill exercise combined with enriched environment intervention(TE+EE)on learning and memory and BDNF/TrkB signaling pathway in frontal lobe of Wistar rats,and to further explore the relationship between treadmill exercise combined with enriched environment intervention,BDNF/TrkB signaling pathway in frontal lobe and learning and memory.In order to reveal the possible molecular mechanism of the combination intervention to improve learning and memory.Research methods:Forty healthy 7-week-old Wistar male rats were randomly divided into control group,enriched environment group,treadmill exercise group and treadmill exercise combined with enriched environment group,with 10 rats in each group.Control group was raised in standard environment;Treadmill exercise group received moderate load treadmill exercise intervention;The enriched environment group received enriched environment intervention;Treadle exercise combined with enriched environment group was treated with moderate load treadmill exercise intervention and enriched environment box intervention for 8 weeks.Morris water maze test was used to evaluate the learning and memory of rats in each group.Real-time PCR(RT-PCR)was used to detect the expression levels of BDNF and TrkB in rats’ frontal lobes.Results:(1)In the Morris water maze experiment,with the increase of the number of days of learning the water maze,the escape latency of rats in the positioning navigation experiment showed a decreasing trend(P<0.01);In space exploration experiments found that compared with control group,the treadmill exercise group,enriched environment,treadmill exercise combined with enriched environment groups of rats in the experiment of space exploration,the number of cross platform were significantly increased(P<0.001),treadmill exercise combined with enriched environment group of rats,through the platform of the number of treadmill exercise,enriched environment group significantly increased(P<0.05),However,there was no statistically significant difference between the treadmill exercise group and the enriched environment group.(2)RT-PCR was used to detect the mRNA levels of BDNF and TrkB in the frontal lobes of rats.Compared with the control group,the mRNA expression levels of BDNF and TrkB in the frontal lobes of rats in the exercise group,the enriched environment group and the exercise combined with the enriched environment group were significantly increased(P<0.01).The mRNA levels of BDNF and TrkB in the frontal lobes of rats in the exercise group and enriched environment group were significantly increased compared with those in the exercise group and enriched environment group(P<0.01),but there was no statistically significant difference between the exercise group and enriched environment group(P>0.05).Conclusion:Through the 8-week intervention study,it was found that the exercise group,the enriched environment group and the exercise combined with the enriched environment group had positive effects on the learning,memory and BDNF/TrkB signaling pathway in the frontal lobes of rats.Compared with the exercise group and the enriched environment group,the exercise combined with the enriched environment group had the best intervention effect.The combination of treadmill exercise and enriched environment may improve learning and memory by regulating the expression level of BDNF/TrkB signaling pathway in rats.