ABSTRACT
BACKGROUND: Interleukin-15 (IL-15), a well-known myokine, is highly expressed in skeletal muscle and is involved in muscle-fat crosstalk. Recently, a role of skeletal muscle-derived IL-15 in the improvement of glucose homeostasis and insulin sensitivity has been proposed. However, little is known regarding the influence of endurance training on IL-15 expression in type 2 diabetic skeletal muscles. We investigated the effect of endurance exercise training on glucose tolerance and IL-15 expression in skeletal muscles using type 2 diabetic animal models. METHODS: Male Zucker diabetic fatty (ZDF) and ZDF lean control (ZLC) rats were randomly divided into three groups: sedentary ZLC, sedentary ZDF (ZDF-Con), and exercised ZDF (ZDF-Ex). The ZDF-Ex rats were forced to run a motor-driven treadmill for 60 minutes once a day 5 times per week for 12 weeks. Intraperitoneal glucose tolerance test (IPGTT) was performed after 12 weeks. Expression of IL-15 was measured using ELISA in extracted soleus (SOL) and gastrocnemius medial muscles. RESULTS: After 12 weeks of treadmill training, reduction of body weight was observed in ZDF-Ex compared to ZDF-Con rats. Glucose tolerance using IPGTT in diabetic rats was significantly improved in ZDF-Ex rats. Furthermore, the expression of IL-15 was significantly increased (P<0.01) only in the SOL of ZDF-Ex rats compared to ZDF-Con. Additionally, IL-15 expression in SOL muscles was negatively correlated with change of body weight (R=-0.424, P=0.04). CONCLUSION: The present study results suggest that 12 weeks of progressive endurance training significantly improved glucose tolerance with concomitant increase of IL-15 expression in SOL muscles of type 2 diabetic rats.
Subject(s)
Animals , Male , Rats , Body Weight , Enzyme-Linked Immunosorbent Assay , Glucose Intolerance , Glucose Tolerance Test , Homeostasis , Insulin Resistance , Interleukin-15 , Muscle, Skeletal , Muscles , Rats, ZuckerABSTRACT
BACKGROUND: Interleukin-15 (IL-15), a well-known myokine, is highly expressed in skeletal muscle and is involved in muscle-fat crosstalk. Recently, a role of skeletal muscle-derived IL-15 in the improvement of glucose homeostasis and insulin sensitivity has been proposed. However, little is known regarding the influence of endurance training on IL-15 expression in type 2 diabetic skeletal muscles. We investigated the effect of endurance exercise training on glucose tolerance and IL-15 expression in skeletal muscles using type 2 diabetic animal models. METHODS: Male Zucker diabetic fatty (ZDF) and ZDF lean control (ZLC) rats were randomly divided into three groups: sedentary ZLC, sedentary ZDF (ZDF-Con), and exercised ZDF (ZDF-Ex). The ZDF-Ex rats were forced to run a motor-driven treadmill for 60 minutes once a day 5 times per week for 12 weeks. Intraperitoneal glucose tolerance test (IPGTT) was performed after 12 weeks. Expression of IL-15 was measured using ELISA in extracted soleus (SOL) and gastrocnemius medial muscles. RESULTS: After 12 weeks of treadmill training, reduction of body weight was observed in ZDF-Ex compared to ZDF-Con rats. Glucose tolerance using IPGTT in diabetic rats was significantly improved in ZDF-Ex rats. Furthermore, the expression of IL-15 was significantly increased (P<0.01) only in the SOL of ZDF-Ex rats compared to ZDF-Con. Additionally, IL-15 expression in SOL muscles was negatively correlated with change of body weight (R=-0.424, P=0.04). CONCLUSION: The present study results suggest that 12 weeks of progressive endurance training significantly improved glucose tolerance with concomitant increase of IL-15 expression in SOL muscles of type 2 diabetic rats.
Subject(s)
Animals , Male , Rats , Body Weight , Enzyme-Linked Immunosorbent Assay , Glucose Intolerance , Glucose Tolerance Test , Homeostasis , Insulin Resistance , Interleukin-15 , Muscle, Skeletal , Muscles , Rats, ZuckerABSTRACT
The aim of this investigation was to determine if resistance exercise improved musculoskeletal embryonic nuclear protein 1 (Mustn1) mRNA expression in skeletal muscle of rat. Thirty-two male Sprague-Dawley rats were separated into sedentary (control group, CON; n=16) and exercise-trained groups (resistance exercise group, REG; n=16). CON and REG subsequently were separated into 4 weeks group (4 weeks CON, 4 weeks REG) and 8 weeks group (8 weeks CON, 8 weeks REG). The rats in the resistance exercise group were trained to climb a 1-m vertical (85 degree incline) ladder with weights secured to their tail, and they climbed the ladder 10 times 3 days per week for 8 weeks progressively. After weeks of exercise, skeletal muscle was taken from the flexor halucis longus. After separating the total ribonucleic acid (RNA) of each group, quantitative polymerase chain reaction was used to analyze RNA quantitatively. After 4 weeks of resistance exercise, Mustn1 mRNA expression increased significantly in REG compared to CON (p<0.001). Additionally, there was a significant increase of Mustn1 mRNA expression in 8 weeks REG compared to 8 weeks CON (p<0.01). Interestingly, there was a significant difference in Mustn1 mRNA between 4 weeks REG and 8 weeks REG (p<0.01). In the REG, Mustn1 mRNA increased by 3.7-fold and 2.1-fold relative to CON, respectively. In conclusion, the resistance training increased Mustn1 mRNA expression in skeletal muscle of rat. This shows that the Mustn1 mRNA expression gives positive effect on myogenesis and muscle regeneration in skeletal muscle of rat results from resistance ladder exercise.