Chronic Electrical Stimulation at Acupoints Reduces Body Weight and Improves Blood Glucose in Obese Rats via Autonomic Pathway

Background: The aim of this study was to investigate effects and mechanisms of chronic electrical stimulation at acupoints (CEA) using surgically implanted electrodes on food intake, body weight, and metabolisms in diet-induced obese (DIO) rats. Methods: Thirty-six DIO rats were chronically implanted with electrodes at acupoints ST-36 (Zusanli). Three sets of parameters were tested: electrical acupuncture (EA) 1 (2-s on, 3-s off, 0.5 ms, 15 Hz, 6 mA), EA2 (same as EA1 but continuous pulses), and EA3 (same as EA2 but 10 mA). A chronic study was then performed to investigate the effects of CEA on body weight and mechanisms involving gastrointestinal hormones and autonomic functions. Results: EA2 significantly reduced food intake without uncomfortable behaviors. CEA at EA2 reduced body weight and epididymal fat pad weight (P < 0.05). CEA reduced both postprandial blood glucose and HbA1c (P < 0.05). CEA delayed gastric emptying (P < 0.03) and increased small intestinal transit (P < 0.02). CEA increased fasting plasma level of glucagon-like peptide-1 (GLP-1) and peptide YY (P < 0.05); the increase of GLP-1 was inversely correlated with postprandial blood glucose (R² = 0.89, P < 0.05); and the plasma ghrelin level remained unchanged. EA increased sympathetic activity (P < 0.01) and reduced vagal activity (P < 0.01). Conclusions: CEA at ST-36 reduces body weight and improves blood glucose possibly attributed to multiple mechanisms involving gastrointestinal motility and hormones via the autonomic pathway.