有氧运动对Ⅱ型糖尿病大鼠结肠肌间神经丛及结肠功能障碍的影响

 目的：观察有氧运动结合不同饮食方式对2型糖尿病大鼠结肠功能的影响，并从肠神经的角度探讨其神经生物学机制，进而为糖尿病胃肠功能紊乱的运动疗法提供理论和实验依据。方法：雄性SD大鼠45只，除正常对照组外其余大鼠经高脂饲养和链脲佐菌素注射建立2型糖尿病大鼠模型，再随机分为普通饲料安静组、普通饲料运动组、高脂饲料安静组和高脂饲料运动组。运动组进行8周无负重游泳训练（60 min/d，5 d/week）。采集血清测口服葡萄糖耐量，结肠组织进行肠张力测试、HE染色以及蛋白基因产物9.5（PGP9.5）、P物质（SP）和血管活性肠肽（VIP）免疫组化检测。结果：（1）糖尿病大鼠结肠肌间神经丛萎缩，神经元数目明显减少，有氧运动在一定程度上抑制上述病理改变；（2）有氧运动结合合理饮食可明显升高糖尿病大鼠结肠SP含量，而高脂膳食结合运动干预未见SP含量明显改善；（3）不同膳食方式结合运动，均能显著提高糖尿病大鼠结肠VIP含量；（4）运动干预后糖尿病大鼠结肠平滑肌萎缩减轻，肌纤维增粗，肠张力显著升高。结论：糖尿病可导致结肠平滑肌萎缩，肠张力下降；有氧运动可通过重塑结肠肌间神经丛而发挥对糖尿病机体结肠结构和功能的适度改善作用。

Effect of aerobic exercise on myenteric plexus and colonic dysfunction in type 2 diabetic rats

AIM: To observe the effect of aerobic exercise and dietary patterns on the colonic function of type 2 diabetic rats and the enteric nervous mechanism.METHODS: The rat model of type 2 diabetes was induced by high-fat diet (HFD) and streptozotocin (30 mg/kg, ip) injection, and the rats were divided into diabetes control (DC) group, HFD group, exercise (E) group and exercise combined with high fat diet (E+HFD) group. Some other healthy rats were arranged into normal control (NC) group. The rats in E group and E+HFD group received 8-week swimming training (5 d/week, 60 min/d). The colon samples were collected at the end of the 8th week for observation of the pathological changes by HE staining and for detection of colonic tension and expression of  protein gene product 9.5(PGP9.5), substance P(SP) and vasoactive intestinal peptide (VIP).RESULTS: Diabetes induced significant myenteric plexus damages and marked reduction of neurons, while exercise protected the enteric nervous system from injuries. The expression of SP significantly increased in the rats with long-term aerobic exercise combined with a reasonable diet. However, high-fat diet combined with exercise did not obviously up-regulate SP. The positive expression of VIP in the colon significantly increased in both E group and E+HFD group. Aerobic exercise attenuated the atrophy and increased the tension in colonic smooth muscles.CONCLUSION: Diabetes induces muscular atrophy and tension attenuation in colonic smooth muscle, which can be reversed in some extent by aerobic exercise through the remolding of enteric nervous system.