The effect of exercise on expression of myokine and angiogenesis mRNA in skeletal muscle of high fat diet induced obese rat

Abstract

[Purpose]The purpose of this study was to investigate the effect of regular treadmill exercise on the mRNA expressions of myokines and angiogenesis factors in the skeletal muscle of obese rats.[Methods]Thirty two male Sprague-Dawley rats (4weeks old) were divided into the CO (control) and HF (high fat diet) groups. Obesity was induced in the HF group by consumption of 45% high-fat diet for 15 weeks. These groups were further subdivided into training groups (COT and HFT); the training groups conducted moderate intensity treadmill training for 8 weeks. Soleus muscles were excised and analyzed by real-time quantitative PCR.[Results]mRNA expression of myokines, such as PGC-1α, IL-6, and IL-15, in the COT and HFT groups (which conducted regular exercise), were higher as compared with the CO and HF groups (p < 0.05). Also, the levels in the HF group were significantly lower when compared with CO group (p < 0.05). Expression of angiogenesis mRNA, namely mTOR, VEGF, and FLT1, were significantly lower in the HF group, as compared to the CO group (p < 0.05). In addition, COT group had a higher expression of mTORC1, mTORC2, VEGF and FLT mRNA, than the CO group (p < 0.05); the HFT group also had higher expressions of mTOR, VEGF and FLT1 mRNA than the HF group (p < 0.05).[Conclusion]These results indicate that mRNA expression of myokines was increased through the activity of muscle contraction, and it also promoted the mRNA expression of angiogenesis due to activation of mTOR. Thus, we conclude that not only under normal health conditions, but in obesity and excess nutritional circumstances also, regular exercise seems to act positively on the glycemic control and insulin sensitivity through the angiogenesis signaling pathway.

Revascularization and muscle adaptation to limb demand ischemia in diet-induced obese mice

“…PGC1α is a master regulator of energy metabolism and can induce skeletal muscle adaptation to exercise [17, 18]. It also controls several pathways associated with angiogenesis [19] and cytokine release [20]. Our results showed a substantial increase in PGC1α mRNA in demand ischemia (Figure 5D).…”

“…Additionally, the expression level of UCP-1 was assessed because it will report on infiltrating adipocyte differentiation which was reported to decrease under demand ischemia. Finally, the expression level of PGC1α was also assessed as it is known to regulate muscle adaptation to exercise-induced metabolic demand [17, 18] as well as several pathways associated with angiogenesis [19] and cytokine release [20]. …”

Diet change and exercise enhance protein expression of CREB, CRTC 2 and lipolitic enzymes in adipocytes of obese mice

“…Our previous study that treadmill training for 8 weeks and dietary changes did not have a positive impact on endocannabinoid system [21]. However, another study that regular exercise is effective in upregulating the mRNA expression of both myokine and angiogenesis factors in the skeletal muscle [22]. …”

Altered bone‐regulating myokine expression in skeletal muscle Of Duchenne muscular dystrophy mouse models

“…Numerous studies have provided evidence that a variety of growth factors and cytokines are actively secreted by muscle tissue. Skeletal muscle, therefore, has been identified as an important endocrine and paracrine organ . The expression and function of those muscle‐derived cytokines (myokines) in DMD have not yet been systemically evaluated.…”