| Objective: To explore the role and molecular mechanism of exosomes in improving adipose tissue inflammation in type 2 diabetic mice,so as to provide theoretical basis for exercise to improve adipose tissue inflammation in type 2 diabetic mellitus and the clinical application of exercise prescription.Methods: Thirty-six 9-week-old male db/db mice were randomly divided into three groups:quiet control group(DA group),ladder climbing group(DP group)and medium intensity treadmill group(DR group)with 12 mice in each group.The DA group did not take exercise,but only carried out normal physiological activities.The DP group carried the tail weight to climb the ladder,and the exercise intensity was 0%,20%,30%,40% and 50% of the weight at the 1st,2nd,3rd-4th,5th-6th and 7th-8th weeks,respectively.Climbing ladder twice was divided into 1 group,3 groups per day,each interval was 30 s,each group was 2 minutes apart,exercise three times a week,exercise every other day,exercise for 8 weeks.The DR group received moderate intensity treadmill exercise with an intensity of 10 m / min,a slope of 0 °,and an exercise time of 45min/ day,5 days/week,8 weeks.The mice in the exercise group received adaptive exercise for a week before formal exercise.At the end of the last exercise,after fasting for 12 hours,the mice were weighed and their fasting blood glucose was measured.The exosomes of adipose tissue were extracted by ultracentrifugation,the exosomes of macrophages were sorted by magnetic beads,and the exosomes were identified by nanoparticle tracking analyzer.The expression of miR-155 in exosomes and adipose tissue was detected by real-time fluorescence quantitative PCR.The expression of peroxisome proliferator-activated receptor gamma(Peroxisome Proliferator-Activated Receptor γ,PPAR γ)in adipose tissue was detected by Western Blot,and the expression of interleukin-6(Interleukin-6,IL-6),tumor necrosis factor-α(Tumor Necrosis Factor-α,TNF-α),monocyte chemoattractant protein-1(Monocyte Chemoattractant Protein-1,MCP-1)and interleukin-10(Interleukin-10,IL-10)in adipose tissue and circulation was detected by flow CBA.Results:1.General indexBody weight: intra-group comparison: the body weight of each group at the 8th week was significantly higher than that at the 0th week(P<0.01 or P<0.001).Comparison between groups:at the 8th week,the body weight in DP group and DR group was significantly lower than that in DA group(P<0.05 or P<0.001),and that in DR group was significantly lower than that in DP group(P<0.01).Blood glucose: Intra-group comparison: fasting blood glucose in DA group increased significantly at week 8 compared with week 0(P<0.05),while fasting blood glucose in DP group and DR group decreased significantly at week 8 compared with week 0(P<0.01).Comparison between groups: at the 8th week,fasting blood glucose in DP group and DR group was significantly lower than that in DA group(P<0.001).There was no significant difference between DP group and DR group.2.The results of NTA identification of exosomesAfter 8 weeks of exosomes,the exosomes particle size of each group was between 30 and120 nm,and there was no significant difference in exosomes concentration among the three groups.3.The results of PCR detection of exosomes body and adipose tissuemiR-155 of exosomes: After 8 weeks of exercise,the miR-155 of exosomes in DP group and DR group was significantly lower than that in DA group(P<0.05 or P<0.01),and the miR-155 of exosomes in DR group was significantly lower than that in DP group(P<0.05).miR-155 of adipose tissue: After 8 weeks of exercise,the miR-155 of adipose tissue in DP group and DR group was significantly lower than that in DA group(P<0.001),and the miR-155 of adipose tissue in DR group was significantly lower than that in DP group(P<0.001).The expression of exosome miR-155 was highly correlated with that of adipose tissue miR-155(r = 0.945,P<0.001).4.The results of western blot detection of adipose tissuePPAR γ: After 8 weeks of exercise,the level of adipose PPAR γ in DP group and DR group was significantly higher than that in DA group(P<0.01 or P<0.001),and PPAR γ in DR group was significantly higher than that in DP group(P<0.01 or P<0.01).5.The results of flow CBA detection of adipose tissue and circulating(1)The results of flow CBA detection of adipose tissueAfter 8 weeks of exercise,the levels of adipose tissue IL-6,TNF-α and MCP-1 in DP group and DR group were significantly lower than those in DA group(P<0.001),and those in DR group were significantly lower than those in DP group(P<0.01 or P<0.001).The adipose tissue IL-10 in DP group and DR group was significantly higher than that in DA group(P<0.01 or P<0.001),and that in DR group was significantly higher than that in DP group(P<0.001).(2)The results of flow CBA detection of circulatingAfter 8 weeks of exercise,the levels of circulating IL-6,TNF-α and MCP-1 in DP group and DR group were significantly lower than those in DA group(P<0.01 or P<0.001),and those in DR group were significantly lower than those in DP group(P<0.05 or P<0.01).The circulating IL-10 in DP group and DR group was significantly higher than that in DA group(P<0.05 or P<0.001),and that in DR group was significantly higher than that in DP group(P<0.001).Conclusions:1.Ladder climbing and moderate intensity treadmill exercise can reduce the body weight and blood glucose of db/db mice and improve the inflammation of adipose tissue.The improvement effect of moderate intensity treadmill is better than that of climbing ladder.2.Ladder climbing and moderate treadmill exercise may improve adipose tissue inflammation by reducing macrophage-derived exosomes miR-155 levels and regulating adipose tissue PPAR γ. |
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