Repeated Application of Low-Frequency Electroacupuncture Improves High-Fructose Diet-Induced Insulin Resistance in Rats

Abstract

Background Insulin resistance is frequently present in obesity and during the development of type 2 diabetes mellitus. Objective The purpose of the present study was to investigate the effect of electroacupuncture (EA) on high-fructose diet (HFD)-induced insulin resistance. Methods Male Wistar rats were fed HFD for 4 weeks and developed insulin resistance. Insulin sensitivity was assessed by clamp. The number of animals was seven, eight and seven in the control, HFD and HFD+EA groups, respectively. AMPactivated protein kinase (AMPK) and glucose transporter 4 (GLUT4) in skeletal muscle were measured by Western blotting analysis (n=7 in each group). EA stimulation was carried out 12 times over 4 weeks at an intensity of 1-3 mA and a frequency of 2/15 Hz in a conscious state without restraint. Results There was no signifi cant difference in mean body weight and fasting blood glucose concentration between groups at the end of the experiment. The mean glucose infusion rate during the clamp was signifi cantly lower in the HFD group than in controls (p<0.05). There was no signifi cant difference in expression of GLUT4 in skeletal muscle in the control and each group. Phosphorylated AMPKα (Thr 172 ) in skeletal muscle showed a signifi cant increase immediately after the fi nal EA stimulation when compared with the control group (p<0.05). Conclusion Repeated application of EA is capable of improving diet-induced insulin resistance, probably through activation of AMPK signalling pathways in skeletal muscle. These results suggest that repeated application of EA may have benefi cial effects on diet-induced insulin resistance. INTRODUCTIONDiabetes mellitus is a metabolic disorder that can lead to a wide range of complications, including coronary artery disease, cerebrovascular disorders, renal failure, blindness and gangrene. The prevalence of diabetes among adults (aged 20-79 years) in 2010 was estimated to be 6.4%, affecting 285 million adults, and will increase to 7.7% (439 million adults) by 2030. 1Insulin resistance is frequently present in obesity and during the development of type 2 diabetes mellitus and is generally defi ned as a reduction in the body's ability to clear a glucose load from circulation in response to insulin. Although there is controversy regarding the relative importance of insulin resistance and impaired β cell function in the pathogenesis of diabetes, some studies have proposed that loss of early insulin response to glucose and poor suppression of hepatic glucose output are primarily responsible for development of the disease.2 Pharmacological agents that reduce insulin resistance are clinically available, but they carry a potential risk of serious complications.3 4 In the last decade, increasing evidence has suggested that electroacupuncture (EA) may improve glucose metabolism by modifying insulin sensitivity.5 6 Studies have suggested that EA increases insulin secretion and/or enhances insulin sensitivity in diabetic and obese rodent models.5 7 However, the electrical stimulation int...

Electroacupuncture Regulates Apoptosis/Proliferation of Intramuscular Interstitial Cells of Cajal and Restores Colonic Motility in Diabetic Constipation Rats

“…Peplow and Baxter [23] found that EAS of 15 Hz with 10 mA for 30 minutes and 60 minutes had a hypoglycemic effect in fasted type 2 diabetic rats. However, blood glucose was not altered following EAS with parameters of 15 Hz with 1–3 mA in type 2 diabetic rats and 20 Hz in type 1 diabetic rats [23, 24]. Similarly, although a different frequency EAS (10/100 Hz, 1–3 mA) was tried, blood glucose in STZ-induced diabetic rats was not significantly altered in the present study.…”

Electroacupuncture inhibits weight gain in diet-induced obese rats by activating hypothalamicLKB1-AMPK signaling

“…Several studies have studied the relationship between EA and AMPK. Tominaga et al [ 18 ] suggested that repeated EA therapy is capable of improving diet-induced insulin resistance, possibly via AMPK signaling activation in skeletal muscle. Immediately after EA stimulation, phospho-AMPKα (Thr172) was significantly higher in animals receiving EA than control animals.…”

Role of AMPKαin Skeletal Muscle Glycometabolism Regulation and Adaptation in relation to Sepsis

“…All of the membranes were incubated at 4°C overnight with anti-Phos-AMPK α -Thr172 antibody (1 : 1000), or anti-AMPK α antibody (1 : 1000) or anti-GLUT4 (1 : 3000), or anti- α -tubulin antibody (1 : 1000) in 5% Carnation instant milk/TBS. After incubating with a secondary antibody (1 : 500) (Beijing Zhongshan Biotechnology, China) in 5% Carnation instant milk-TBS-Tween 20, the blots were developed using enhanced chemiluminescence according to the manual (Biological Industries, Beit Haemerk LTD, Israel) and exposed to X-ray film [22]. Normalization of protein expression was carried out using α -tubulin as control.…”