小檗碱抑制肠道二肽基肽酶-Ⅳ的降糖机制研究

目的：探讨短疗程口服小檗碱对糖尿病大鼠模型的作用及相关机制。方法：取健康雄性SD大鼠60只，采用腹腔注射链脲佐菌素建立糖尿病大鼠模型，其中造模成功50只，按照每天灌喂不同药物将大鼠随机分为五组：模型对照组，西格列汀组（磷酸西格列汀10 mg/kg）和小檗碱小剂量组（小檗碱30 mg/kg）、中剂量组（小檗碱60 mg/kg）、大剂量组（小檗碱120 mg/kg）。第三天早晨空腹采血，喂药后半小时予灌喂50%葡萄糖水（2 g/kg），灌喂葡萄糖2 h时采集血液和肠道标本，采用生化分析仪检测空腹血糖及餐后2 h血糖，采用ELISA法检测餐后2 h血胰岛素、胰高血糖素样肽-1（GLP-1）、二肽基肽酶-Ⅳ（DPP-Ⅳ）及局部肠道组织GLP-1、DPP-Ⅳ含量。结果：干预后小檗碱各剂量组的空腹血糖水平、餐后2 h血DPP-Ⅳ水平与模型对照组差异无统计学意义（均P>0.05）；小檗碱中、大剂量组的餐后2 h血GLP-1水平、血胰岛素水平比模型对照组升高，餐后2 h血糖水平比模型对照组降低（均P<0.05）；小檗碱各剂量组的肠道组织餐后2 h GLP-1含量比模型对照组增加，餐后2 h肠道组织DPP-Ⅳ含量比模型对照组减少（均P<0.05）。结论：短疗程口服中、大剂量小檗碱能降低糖尿病大鼠模型的餐后血糖，抑制肠道局部的DPP-Ⅳ可能是口服小檗碱的降糖机制之一，DPP-Ⅳ抑制剂的疗效可能与该药的肠道药代动力学有关。
Abstract: Objective: To investigate the effect of berberine on glycemia regulation in rats with diabetes and the related mechanisms. Methods: Diabetic-like rat model was successfully induced by intraperitoneal injection of streptozotocin in 50 out of 60 male SD rats, which were then randomly divided into 5 groups with 10 rats in each:control group (received vehicle only), positive drug control group (sitagliptin 10 mg·kg-1·d-1), low-dose berberine group (30 mg·kg-1·d-1), moderate-dose berberine group (60 mg·kg-1·d-1), and high-dose berberine group (120 mg·kg-1·d-1). All animals were fed for 3 d, and fasting blood sampling was performed on day 3 of administration. Rats were given glucose (2 g/kg) by gavage 30 min after the last dose. Blood and intestinal samples were obtained 2 h after glucose loading. Fasting blood glucose (FBG) and 2-h postprandial plasma glucose (2h-PPG) were detected by using biochemical analyzer, and insulin, glucagon-like peptide-1 (GLP-1) and dipeptidyl peptidase-Ⅳ(DPP-Ⅳ) were measured by using ELISA kit. Results: No significant difference in FBG and serum DPP-Ⅳ level were found between berberine groups and control group (all P>0.05). Compared with control group, serum levels of GLP-1 and insulin were increased in high-and moderate-dose berberine groups, while 2h-PPG was decreased (all P<0.05); GLP-1 levels in the intestinal samples were increased, while DPP-Ⅳ levels were decreased in all berberine groups (all P<0.05). Conclusions: Short-term berberine administration can decrease 2h-PPG level in streptozotocin-induced diabetic rat model through local inhibition of intestinal DPP-Ⅳ. The efficacy of DPP-Ⅳ inhibitor may be associated with its intestinal pharmacokinetics. Key words: Diabetes mellitus/drug therapy Berberine/pharmacology Berberine/administration & dosage Glucagon-like peptide 1/drug effects Antigens, CD26/drug effects Blood glucose/blood Diabetes mellitus, experimental