The Regulation Of Adipokines And Irisin In Obesity Rats During Swimming Training

Objective:In the present study, high-fat diet(HD)-induced obese male SD rats were subjected to swimming intervention at the middle-level exercise intensity. The adipokines and myokines as well as corresponding regulatory factors associated with lipid metabolism were detected before and after swimming intervention through rat model with obesity. The aim of this study is to explore the molecular mechanisms of exercise intervention for the prevention and treatment of obesity, which will provide the references for further exploration and development of targeted intervention strategies for the prevention and treatment of obesity.Methods: Totally 80 male SD rats were randomly divided into 3 groups:Control group(C) with 10 rats, high-fat diet plus exercise(HDE) group with 15 rats, and high-fat diet(HD) group with 55 rats. The rats from HDE group were simultaneously provided with high fat diet and swimming training for 16 weeks. The protocols of swimming training include adaptive swimming training for 3 days at the first week and then 90 min swimming training for 6 days and the rest for one day in a week. The swimming training was last for 8 weeks. Following HD induction for 8 weeks, 30 obese rats with significant change in body weight before and after HD induction were divided into another two sub-groups: O group and obese rats subjected to swimming intervention(OE) group with 15 rats in each group. Then, the rats from OE group were provided with swimming intervention at similar exercise intensity for 8 consecutive weeks. After the last swimming, blood and gastrocnemius samples were collected. The concentrations of triglyceride(TG), total cholesterol(TC), high density lipoprotein(HDL), and low density lipoprotein(LDL) were determined by biochemical assay kits, the level of Irisin in serum was evaluated by ELISA, and the protein expression of corresponding regulatory factors including ADP, LEP, AMPK and PGC-1α associated with lipid metabolism signal pathways in gastrocnemius muscle was evaluated by Western blotting.Results:1) The body weights of rats from O group were significantly higher than that from Cgroup(p < 0.05). After swimming intervention for 8 consecutive weeks, the body weights ofrats from HDE group revealed a significant reduction when compared with that from O group(p < 0.05).2) The concentrations of serum TC in rats from O and OE groups were significantly higher than that from C group and HDE group(p < 0.01 and p < 0.05). Serum HDL level from O group was significantly lower than that from C group(p < 0.05) and HDE group(p < 0.05); similarly, serum HDL level from OE group was significantly lower than that from HDE group(p < 0.05).3) After swimming intervention for 8 weeks, the serum Irisin level from O group was significantly lower than that of C group and HDE group(p < 0.05).4) The protein expression of LEP in O group was significantly up-regulated when compared with that from C group(p < 0.05); in contrast, in HDE and OE group, the protein expression of LEP was significantly reduced when compared with that of O group(p < 0.05). Similarly, the protein expression of ADP in HDE group was significantly decreased when compared with that from C group(P < 0.05); in contrast, swimming intervention could result in the significant up-regulation of ADP when compared with that from C group and O group(p < 0.05).5) The protein expression of PGC-1α and Irisin in O group were significantly decreased when compared with C group(p < 0.05); in contrast, in HDE group and OE group, the expression of PGC-1α and Irisin were significantly up-regulated when compared with O group and C group(p < 0.05).Conclusions: 1, HD-induced disorder of lipid metabolism in obese rats can be significantly rescued by long-term swimming training at middle-level exercise intensity. 2, Long-term swimming training at middle-level exercise intensity can up-regulate the expression of ADP and reduce the expression of LEP in gastrocnemius muscle of rats, thereby delaying the development of obesity. 3, Long-term swimming training at middle-level exercise intensity can enhance the generation of Irisin in different tissues and promote the secretion of Irisin, which may inhibit the occurrence and development of obesity through the activation of PGC-1α-Irisin pathway. Therefore, appropriate and regular exercise training such as swimming can up-regulate the expression of ADP and Irisin, which is benefit for the prevention and treatment of obesity. Meanwhile, in the present study, exercise-induced activation of irisin signal pathway could be a novel and effective target for the prevention and treatment obesity, which needs to be further explored.