The effect and mechanism of apelin-13 on diabetes-associated sarcopenia in rats / 中华老年医学杂志

ABSTRACT

Objective:To observe the effect of Apelin-13 on diabetes-related sarcopenia in rats model and explore the underlying mechanism.Methods:This experiments were divided into 3 groups.In the normal control group, Wistar rats were fed by ordinary feed, intraperitoneally injected daily with the equal amount of normal saline.In the model+ control group, diabetic-related sarcopenia model was established in rats with fat-fed Goto-Kakizaki rats for 12 weeks and intraperitoneally injected daily with the equal amount of normal saline.In the model+ apelin-13 group, apelin-13(0.1 mol/kg)was intraperitoneally injected into diabetic-related sarcopenia model daily for 12 weeks.The water intake, food intake, and body weight were measured.The fasting blood glucose, fasting insulin and blood lipid levels of rats were measured, and the insulin resistance index was calculated.The wet weight of the rats' gastrocnemius muscle was weighed, and the morphological changes of the gastrocnemius muscle were observed.Western blot was used to detect the protein expressions of phosphatidylinositol-3 kinase(PI3K)and phosphorylated Akt(p-Akt)in the gastrocnemius muscle of rats.Results:Compared with the model+ normal saline group, the model+ apelin-13 group showed that the following parameters were significantly improved.(1)The water intake of rats was significantly decreased at 8, and 12 weeks( F=7.17 and 7.91), and food intake was significantly decreased( F=5.84 and 6.12)and body weight were significantly increased at 8 and 12 weeks( F=5.76 and 6.07)(all P<0.05). (2)The levels of fasting blood glucose were significantly decreased at 8 and 12 weeks( F=8.07 and 8.24, all P<0.05). (3)Serum triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, the levels fasting insulin and the insulin resistance index were significantly decreased at week 12( F=5.17, 7.94, 10.27, 8.32, 6.94 and 11.31, all P<0.05); (4)The wet weight of gastrocnemius muscle was significantly increased(0.63±0.04 g and 1.02±0.05 g, t=4.32, P<0.05). (5)Compared with the model+ normal saline group, the model+ apelin-13 group showed the protein expressions of PI3K and p-Akt in the gastrocnemius muscle of rats were significantly up-regulated( t=7.32, 8.07, both P<0.05). Conclusions:Apelin-13 has an inhibitory effect on diabetes-related sarcopenia, and its mechanism may be related to the up-regulation of PI3K and p-Akt expression in skeletal muscle.