黄连解毒汤对糖耐量减低大鼠的糖尿病延缓作用

Effects of huang-ilan-jie-du-decoction in delaying diabetes in rats with impaired glucose tolerance

目的观察黄连解毒汤对糖耐量减低（IGT）Zucker糖尿病肥胖（ZDF，fa／fa）大鼠糖尿病发病的延缓作用并探讨相关机制。方法以高脂饲料诱导20只ZDF大鼠至IGT期后，将大鼠按随机数字表法分为模型组及黄连解毒汤干预组（黄连组），每组10只，并以ZuckerLean（fa／＋）大鼠作为正常对照组，其中，黄连组以黄连解毒汤0．075g／d灌胃干预，模型组及正常对照组以同体积双蒸水对照，以干预3周后，模型组全部发展至糖尿病为实验终点。行口服葡萄糖耐量试验（OGTT）观察黄连组糖尿病发病率。以酶联免疫吸附法（ELISA）测定血浆脂多糖、胰高血糖素样肽-1（GLP-1）、胰岛素及胰高血糖素（GC）水平，并以稳态模型评估-胰岛素抵抗指数（HOMA-IR）评价胰岛素抵抗；以免疫组化方法观察不同组间回肠occludin、zonula occludens（ZO）-1、核因子-κB和肿瘤坏死因子（TNF）-α的表达。结果药物干预3周后，模型组全部发展为糖尿病，而黄连组仅50％发展为糖尿病，且与模型组相比，黄连组空腹血糖水平（F=13．940，P〈0．01）显著下降。随着糖尿病病程进展，模型组大鼠空腹血浆GC（F=51．045，P〈0．01）、HOMA-IR（F=19．260，P〈0．01）、脂多糖（F=10．661，P〈0．05）、GLP-1（F=7．077，P〈0．01）水平逐渐升高，而胰岛素（F=13．445，P〈0．01）水平逐渐下降；干预3周后，与模型组相比，黄连组胰岛素（F=1．020，P〉0．05）、HOMA—IR（F=13．227，P〈0．01）、GC（F=23．440，P〈0.05）、脂多糖（F=22．636，P〈0．01）水平均有不同程度下降，GLP-1水平升高（F=4．954，P〈0.05）。在回肠，与正常对照组相比，模型组核因子．KB（F=91．951，P〈0．01）和TNF-α（F=83．633，P〈0．01）的表达增加，而occludin（F=105．653，P〈0．01）及ZO-1（F=71．753，P〈0．01）表达明显减少。黄连组上述指标均有明显改善（P均〈0．01）。结论黄连解毒汤可能通过改善GLP-1的分泌、减轻肠道炎性反应并维持肠道屏障功能，对IGT期ZDF大鼠有延缓T2DM发病的作用。

Objective To investigate the effects of huang-lian-jie-du-decoction in delaying diabetes in Zucker diabetes fat （ZDF, fa/fa） rats with impaired glucose tolerance （IGT） and its related mechanisms. Methods High fat diet was used to induce IGT in ZDF rats. Twenty rats were divided into model group and huang-lian-jie-du-decoction intervention group（huang-lian group） in accordance with the random number table once they entered into the stage of IGT with ten rats in each group. Zucker Lean （ZL, fa/＋ ） rats were used as normal control group. Rats in huang-lian group were treated with huang-lian-jie-du-decoction at dose of 0. 075 g/d, whereas rats in the model group and normal control group received the same vol- ume of distilled water as vehicle. The interventions were terminated when all rats in model group developed diabetes after three weeks of intervention. Incidence of diabetes was calculated by oral glucose tolerance test （OGTF） in huang-lian group. Plasma lipopolysaccharide （ LPS）, glueagon-like peptide-1 （ GLP-1 ）, insulin and glucagon （GC） were measured by enzyme linked immunosorbent assay （ELISA）, and homeostasis model assessment of insulin resistance （HOMA-IR） index was calculated to evaluate insulin resistance. Immunohistochemistry method was used to observe the expression of oecludin, zonula occludens （ZO） -1, nuclear factor-κB and tumor necrosis factor-α（TNF-α） in different groups. Results After 3 weeks of intervention, all rats in model group developed diabetes whereas only 50% rats in huang-lian group developed diabetes. And fasting blood glucose was decreased in huang-lian group compared with model group （ F = 13. 940, P 〈 0.01 ）. During the progression of diabetes, the fasting plasma GC （ F = 51. 045, P 〈 0.01 ）, HOMA-IR （ F = 19. 260, P 〈0.01 ）, LPS （F = 10.661, P 〈0.05） and GLP-1 levels （F =7. 077, P 〈0.01 ） of mod- el group were gradually increased, while insulin level（ F = 13. 445, P 〈 0.01 ） was gradually decreased. Af- ter 3 weeks of treatment, compared with model group, insulin （ F= 1.020, P 〉0.05 ） , HOMA-IR （F=13.227, P〈0.01）, GC （F=23.440, P〈0.05） and LPS （F=22.656, P〈0.01） of huang-lian group were decreased, but GLP-1 level （ F = 4. 954, P 〈 0.05 ） was increased. Compared with normal control group, the expression of nuclear factor-κB （ F=91.951, P〈0.01 ） and TNF-α （ F=83.633, F〈0.01） in ileum of model group were increased, and the expression of occludin （F=105.653, P 〈 0.01 ） and ZO-1 （ F = 71. 753, P 〈 0.01 ） in ileum decreased significantly. The above indexes were improved obviously in huang-lian group （all P 〈 0.01 ）. Conclusion Huang-lian-jie-du-decoction may delay the onset of type 2 diabetes in ZDF rats with IGT by improving the secretion of GLP-1, reducing intestinal in- flammation and protecting the intestinal barrier function.