[The effects of different exercise modes on Rab5 protein and glucose metabolism in skeletal muscle of type 2 diabetic mellitus rats].

Objective: To investigate the effects of continuing exercise and load-bearing interval exercise on skeletal muscle tissue cell morphology, Ras-related proteins 5 (Rab5) mRNA and protein expression and glucose metabolism in skeletal muscle of type 2 diabetic mellitus (T2DM) rats. Methods: Eight SD rats were selected as controls group (CR), the others SD rats were fed with high fat and high sugar diet for 6 weeks before injecting STZ (35 mg/kg) to construct the T2DM model. Twenty-four T2DM rats were randomly devided into T2DM model group (DRM), continuing exercise group (DCRE) and load-bearing interval exercise group (DWRE), 8 rats in each group. DCRE exercise protocol, that was 15 m/min (10 min), 20 m/min (40 min), 15 m/min (10 min), during the first 1～2 weeks, and 18 m/min (10 min), 25 m/min (40 min), 15 m/min (10 min), during the second 3～8 weeks. DWRE exercise protocol: load weight 15% / 1～2 weeks, 30% / 3～4 weeks, 45% / 5～8 weeks, with 15 m/min (5 min), 12 groups and 3 min rest between groups. After 8 weeks, pathological and morphological changes of skeletal muscle were observed by HE. Rab5 and Glucose transporte 4 (GLUT4) mRNA expressions of skeletal muscle were tested by qRT-PCR. Rab5 protein expression in skeletal muscle was tested by immunofluorescence histochemistry and Western blot, and plasma Rab5 and Glycosylated Hemoglobin (GHb) concentrations were detected by ELISA. Results: Comparison with CR, DRM showed pathological damage of skeletal muscle, the expressions of Rab5 mRNA, protein and GLUT4 mRNA were all decreased in skeletal muscle (P＜0.01), the serum levels of Rab5 and GHb were both significantly elevated (P＜0.01). Comparison with DRM, both DCRE and DWRE significantly improved pathological damages of skeletal muscle, the expressions of Rab5 mRNA, protein and GLUT4 mRNA were all increased in skeletal muscle (P＜ 0.05, P＜0.01), the serum levels of Rab5 and GHb were decreased (P＜0.05, P＜0.01), and there was no statistical difference between DCRE and DWRE groups (P＞0.05). Conclusion: Two exercise modes can improve the pathological injury of skeletal muscle in type 2 diabetic rats, and enhance GLUT4 transport capacity by improving the expression of Rab5 gene and protein in skeletal muscle, and alleviate the imbalance of glucose metabolism homeostasis in skeletal muscle. However, there was no significant difference between the effects of two exercise modes on Rab5 protein and glucose metabolism in skeletal muscle.

[Effect of exercise on adiponectin in aged obese rats].

OBJECTIVE: To explore effects of exercise on the expression of adiponectin mRNA and protein in visceral adipose tissue, plasma adiponectin concentration, and insulin resistance of aged obese rats. METHODS: Male SD rats age to 21 days old were fed with high-fat diet (fat percentage was 36.3% to 40.0%) for three stages of adolescence, maturity and old age to establish elderly obesity rats model. When the rats aged to 60 weeks old, natural growing elderly rats were randomly divided into control group (C) and aged exercise group (AE), n=6; elderly obesity rats were randomly divided into obesity control group (OC) and obesity exercise group (OE), n=6. The treadmill grade was 0°, the exercise speed and time were 15 m/min×15 min, 4 groups each time, between consecutive groups the rats had 5 minutes rest, the rats were exercised for 60 minutes every day, five days a week, continuous exercise for 8 weeks. Then, the expressions of adiponectin mRNA and protein in visceral adipose tissue were determined. The concentrations of blood glucose, plasma adiponectin and insulin were measured. Insulin resistance was calculated. RESULTS: Comparison with control group, the expressions of adiponectin mRNA and protein were obviously decreased, the concentration of blood glucose and insulin resistance were significantly increased in obesity control group, while the expressions of adiponectin mRNA and protein were obviously increased. Comparison with obesity control group, the expressions of adiponectin mRNA and protein, the concentration of plasma adiponectin were obviously increased, the concentration of blood glucose and insulin resistance were significantly decreased in obesity exercise group. CONCLUSIONS: Adiponectin mRNA and protein expression in visceral adipose tissue is decreased and accompanied by high blood glucose and insulin resistance in elderly obesity rats. Exercise can increase the adiponectin mRNA and protein expression in visceral adipose tissue, elevate levels of plasma adiponectin, and decrease the level of blood glucose and insulin resistance in elderly obesity rats.

[Effects of different intensities exercise combined with resveratrol on RBP4 in aged obese rats].

OBJECTIVE: To investigate the effects of different intensity exercise combined with resveratrol on retinol binding protein 4(RBP4) mRNA and protein expression in visceral adipose tissue and plasma RBP4 concentration of aged obese rats. METHODS: Eighty male SD rats aged 3 weeks were randomly divided into the control group and the experimental group. Rats of the control group(C) were fed with ordinary feed of 6% fat (n=12). The experimental group consisted of 68 rats, which were fed with 36%~40% high fat feed in three stages. The rat model of elderly obesity was established successfully. Twenty-four obese rats were selected and randomly divided into 4 groups, including obese group (CO), resveratrol obese group (RO), low intensity exercise combined with resveratrol group (LRO) and moderate intensity exercise combined with resveratrol group (MRO). There were 6 rats in each group. The exercise intensities of the LRO group and MRO group were (12 m/min×15 min) and (15 m/min×15 min). Every day was exercised for 60 minutes. The rats in RO, LRO or MRO were treated with resveratrol at the dose of 52.5 mg/kg·d, while the rats in the control group were fed with the same amount of purified water, continued intervention for 8 weeks. After 8 weeks, samples of blood, adipose tissue of around the kidney, testicle, vessel and visceral were collected. Blood glucose and plasma RBP4 concentration were measured. Insulin sensitivity(ISI) was calculated. The expressions of RBP4 mRNA and protein were also determined. RESULTS: Compared with normal (C) group, the expressions of RBP4 mRNA and protein and plasma concentration and plasma glucose of the model (CO) group were increased obviously (P<0.05, P<0.01). ISI was decreased obviously (P<0.05). Compared with model (CO) group, the expressions of RBP4 mRNA and protein and plasma concentration and plasma glucose of the RO and LRO and MRO groups were decreased significantly(P<0.05, P<0.01), while ISI was increased markedly (P<0.05). Compared with the RO and LRO groups, the expressions of RBP4 mRNA and protein and plasma concentration and plasma glucose of the MRO group were decreased, while ISI was increased, but there was no significant difference. CONCLUSIONS: Different intensities exercise combined with resveratrol could reduce the RBP4 mRNA and protein expression in visceral adipose tissue and plasma RBP4 concentrations of aged obese rats, but less affected by exercise intensity.