Effect of emodin and berberine on gastrointestinal motility in type 2 diabetic rats
Lu-Hong Yang, Fu-Er Lu, Hui Dong, Li-Jun Xu, Kai-Fu Wang, Institute of Integrative Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
AIM: To compare the effects of emodin and berberine on the gastrointestinal motility of type 2 diabetic rats and to investigate their mechanisms. METHODS: Seventy-two male Wistar rats were randomly divided into six groups, i.e., control, model, emodin, berberine, emodin plus berberine, and cisapride groups. Murine type 2 diabetes model was induced by intravenous injection of a small dose of streptozotocin plus high fat high caloric laboratory chow. The rats were treated with emodin, berberine, emodin puls berberine, or cisapride for 10 weeks. 10% mixed fluid of Arabic gum and charcoal powder was given to the animals by lavage to measure the gastrointestinal propulsive index before sacrifice. The blood glucose and serum triglycerides (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) were determined by biochemical methods. Plasma and tissue levels of substance P (SP), somatostatin (SS), vasoactive intestinal polypetide (VIP) were determined using radioimmunoassay. RESULTS: In the mice treated with emodin, berberine, or emodin puls berberine, blood glucose (8.87±1.3, 7.9±1.2, 7.7±1.3), serum TG (0.57±0.39,0.61 ±0.22,0.59±0.27) and TC (1.79±0.58,1.85±0.42,1.70±0.62) were significantly lower than those in model group (10.3±1.7, 1.47±0.45, 2.18±0.17 for glucose, TG and TC, respectively, P0.05 or P0.01). The murine gastrointestinal propulsive index in model group was decreased remarkably as compared with normal group (52.3±7.9 vs 60.7±12.5, P0.01), while those in emodin and emodin puls berberine groups were significantly elevated in comparison with model group (63.4±9.9,62.7±5.7 vs 52.3±7.9, P0.01). In contrast, the index in berberine group was even lower than that in model group (46.5±8.7, P0.05). Compared with normal group, plasma and intestine levels of SS and VIP (SS:18.7±6.5, 47.8±14.8;VIP: 26.5±6.5,28.8±12.3) in model group were significantly raised (P0.01), while plasma SP (35.6±6.5) was decreased and tissue SP (70.6±20.7) was increased significantly (P0.01). In comparison with model group, plasma and intestine levels of SS and VIP (SS:15.5±3.6, 14.6±5.6; VIP:26.5±6.5,28.8±12.3) in emodin and emodin puls berberine groups were significantly reduced (P0.01), but plasma SP levels in both groups were significantly increased (44.2±5.9, 45.2±6.6, P0.01). CONCLUSION: Berberine inhibits, while emodin promotes the gastrointestinal motility in type 2 diabetic rats. The combined application of both drugs not only reduces blood glucose and adjusts lipid profile, but also improves the gastrointestinal motility. The enhacement of the gastrointestinal motility by emodin might be partially explained by its rectification of the aberrant expression of gastrointestinal hormones.