Aerobic Exercise Enhances Vascular Endothelial And Cognitive Function In Mice Through The Mediation Of Circulating EPC-EX

Background:Endothelial progenitor cells(EPC)regulate endothelial function and promote angiogenesis by releasing Exosomes(EX).Exercise promotes EPC mobilization,increases the amount and activity of circulating EPC,and improves endothelial function.However,it remains to be further explored whether EPC-EX plays a role in motor-mediated improvement of endothelial function.This study aims to explore the influence of exercise intervention on circulating EPC-EX in mice,preliminatively reveal the role of EPC-EX in the process of improving endothelial function through exercise and explore the possibility of circulating EPC-EX improving cognitive function by improving vascular endothelial function and thereby increasing brain blood flow.Method:C57BL/6J male mice(10 weeks of age)were randomly divided into exercise group(ET)and control group(CON).After the 10-week exercise intervention,The ET and CON groups were compared for activity,social competence,working memory and learning memory with the use of behavioral tests.Laser speckle contrast imaging was used to monitor the changes in cerebral blood flow.Endothelium-dependent vasodilation was assessed using vascular reactivity experiments using isolated mouse mesenteric aortic rings.CD34/VEGFR2 double-positive EPC-EX was isolated by antibiotin microbeads from the circulating EX of two groups mice and was quantitatively analyzed by nanoparticle tracking analysis.To explore the effect of exercise-derived EPC-EX on endothelial cell proliferation,EPC-EX from ET was co-cultured with high glucose,palmitic acid(PA),angiotensin Ⅱ(Ang Ⅱ)and OX-LDL induced endothelial cell injury model.Endothelial cell proliferation was detected with CCK-8 assay at 24,48 and 72 h.Results:(1)By evaluating the cognitive function of the model mice,we found that the percentage of sniffing time given to Stranger 2 in the ET was significantly higher than in the CON in the social behavior test;In the Y maze,mice in the ET performed significantly better than those in the CON,both in terms of the number and percentage of successful alternations.There was no significant difference between the two groups of mice in the open field test and the novel object recognition assay.The above experimental data show that 10-weeks-exercise improved working memory and social interaction in mice but did not significantly affect learning memory and activity.(2)By comparing the vascular function of mice in both groups,we found that endothelium-dependent vasodilation of mesenteric artery in ET was significantly better than that in the CON;The ET had greater whole brain blood flow than the CON,with significantly greater blood flow in the superior sagittal sinus,the bridging vein-superior sagittal sinus complex,and confluence of sinuses than the CON.These results suggest that the 10-week exercise intervention improved endothelial function and increased cerebral blood flow in mice.(3)The circulating EX from the two groups of mice was isolated and verified.The average diameter of the particles was 117.4 ± 8.0 nm,and the particles expressing EX specific markers CD63 and TGS101 were defined as EX particles.Microbeads were used to isolate CD34/VEGFR2 double-positive EPC-EX and perform quantitative analyses.We found that the number of 80-150 nm particles in the ET was significantly more than in the CON,indicating that the exercise intervention increases the number of circulating EPC-EX in the mice.(4)We produced the endothelial cell injury model.Compared with normal endothelial cells,endothelial cells treated with high glucose,PA,OX-LDL and Ang Ⅱ showed significantly worse proliferation at 24,48 and 72 h,while the ET showed significantly better proliferation after addition of EPC-EX.In the cell models with high glucose and Ang Ⅱ induced injury,EPC-EX from the ET was significantly better than that from the CON.In the cell model with high glucose,PA and Ang Ⅱ induced damage,EPC-EX with higher concentration was significantly more protective than EPC-EX with lower concentration.No significant difference was observed between ET and CON,or between higher and lower concentrations of EPC-EX in the cell model of OX-LDL induced injury.Conclusion:In conclusion,the conclusion of present study is that exercise intervention can increase the number of circulating EPC-EX in mice and repair endothelial injury by enhancing the protective effect of EPC-EX on proliferation of endothelial cells.This mechanism may be related to the up/down-regulation of mi RNA expression performed by the circulating EPC-EX.Furthermore,our experimental data suggest that exercise interventions may improve working memory and social skills in mice by improving endothelium-dependent vasodilation function and increasing cerebral blood flow.Our study sets the stage for further exploration of the molecular mechanisms underlying endothelial injury repair through exercise-derived EPC-EX and the potential relationship between endothelial function and cognitive function.