Objective: To observe the effect of electroacupuncture (EA) at "Tianshu" (ST25) on nitrergic neurons in jejunum and distal colon in type 2 diabetic rats, so as to explore its mechanism of regulating different intestinal segments.
Methods: Twenty-four SD rats were randomly divided into control, model and EA groups (n=8 in each group). The diabetes model was established by intraperitoneal injection of streptozotocin (35 mg/kg) and high-sugar and high-fat diet for 2 weeks. EA (2 Hz/15 Hz, 2 mA) was applied to bilateral ST25 for 20 min, once a day, 6 days a week for 4 weeks. The intestinal motility was evaluated by observing the first red stool excretion time and the distal colon bead excretion time. HE staining was used to observe the histological changes of jejunum and distal colon. The positive expression and protein expression of intestinal total neuronal marker protein gene product 9.5（PGP9.5） and neuronal nitric oxide synthase (nNOS) in jejunum and distal colon were detected by immunofluorescence staining and Western blot, respectively.
Results: After modeling, the blood glucose was significantly increased (P<0.01), the first red stool excretion time and the distal colon bead excretion time were shortened (P<0.01), the expression levels of PGP9.5 and nNOS in jejunum and distal colon were decreased (P<0.01) in the model group relevant to the control group. After treatment, compared with the model group, the blood glucose was decreased (P<0.01), the first red stool excretion time and the distal colon bead excretion time were prolonged (P<0.01, P<0.05), and the expression levels of PGP9.5 and nNOS in jejunum and distal colon were increased (P<0.05, P<0.01) in the EA group. HE staining showed disordered structure in intestinal mucosa of the jejunum and distal colon, and reduction of the number of goblet cells in the model group, which was relatively milder in the EA group.
Conclusion: EA can effectively improve the intestinal mucosal damage and restore intestinal motor function in type 2 diabetic rats, which may be related to its function in regulating the number of nitrergic neurons in the intestinal nervous system.
目的：观察电针“天枢”对2型糖尿病大鼠空肠及远端结肠氮能神经元的影响, 探讨电针对2型糖尿病大鼠不同肠段的局部调节机制。方法：SD大鼠随机分为正常组、模型组、电针组, 每组8只。采用高脂高糖饮食联合链脲佐菌素诱导2型糖尿病大鼠模型。电针组予“天枢”电针治疗, 20 min/次, 每日1次, 每周6 d, 共治疗4周。通过观察大鼠首粒红便排出时间、远端结肠排珠时间, 评估肠运动情况；采用苏木精-伊红染色法观察大鼠空肠及远端结肠组织形态变化；免疫荧光法及Western blot法检测大鼠空肠及远端结肠中肠总神经元标志物蛋白基因产物（PGP）9.5、氮能神经元标志物神经型一氧化氮合酶(nNOS)的阳性表达及蛋白表达量。结果：与正常组比较, 模型组大鼠随机血糖、空腹血糖水平明显升高(P<0.01), 首粒红便排出时间、远端结肠排珠时间均缩短(P<0.01), 空肠及远端结肠组织中PGP9.5、nNOS的表达水平均降低(P<0.01)。与模型组比较, 电针组大鼠随机血糖、空腹血糖水平明显降低(P<0.01), 首粒红便排出时间、远端结肠排珠时间均延长(P<0.01, P<0.05), 空肠及远端结肠组织中PGP9.5、nNOS表达水平均升高(P<0.05, P<0.01)。光镜下正常组大鼠空肠组织肠黏膜结构完整, 杯状细胞清晰可见, 腺体排列整齐；模型组大鼠空肠及远端结肠肠黏膜结构紊乱, 杯状细胞数量减少, 腺体数量减少、排列杂乱；电针组空肠和远端结肠肠黏膜破坏程度减轻, 杯状细胞数量增加, 肠黏膜腺体排列较整齐、结构完整。结论：电针可通过调节肠神经系统中氮能神经元的数量, 有效改善2型糖尿病大鼠肠道黏膜损伤, 恢复肠运动功能。.
Keywords: Electroacupuncture; Intestinal motility disorder; Neuronal nitric oxide synthase; Nitrergic neurons; Type 2 diabetes.