【作者】 朱占永；

【导师】 吴毅平；

【作者基本信息】 华中科技大学 ， 外科学， 2011， 博士

【摘要】 目的：用GK大鼠建立袖状胃切除术手术模型,借助此模型来探讨袖状胃切除术(SG)对血糖的控制效果。方法：23只GK大鼠随机分为袖状胃切除组(SG)、假手术组(sham-SG)和饮食配对组(PF)。体重、进食量、空腹血糖、口服葡萄糖耐量试验(OGTT)、胰岛素耐量试验(ITT)和空腹胰岛素浓度在特定的时间内被检测。结果：SG手术模型的成功率为100%。自术后第4周起,SG和PF组与sham-SG组间的体重增量有着明显的统计学意义(P<0.01)。SG组空腹血糖水平较sham-SG和PF组明显改善。SG组较PF组和sham-SG组明显改善对葡萄糖耐量的水平,手术后第2周葡萄糖耐量曲线下面积(AUC)较术前减少约28.1%(P<0.01),较饮食配对组减少约21%(P<0.01)。SG组大鼠术后胰岛素耐量和胰岛素抵抗指数(HOMA-IR)较sham-SG和PF组明显改善。结论：SG能够直接控制2型糖尿病而不是继发于体重减轻的效果。SG是一种相对稳定的降糖手术模型。目的：探讨袖状胃切除术的降糖作用及其机制。方法：随机将GK大鼠分为袖状胃切除(SG)组、假手术(sham-SG)组、饮食配对(PF)组和空白对照(Control)组。动态观察手术前和手术后24周中各组大鼠体重、空腹血糖、口服葡萄糖耐量试验(OGTT)、胰岛素耐量试验(ITT)、胰岛素、Ghrelin及GLP-1浓度的变化。结果：自术后第4周起,SG和PF组与sham-SG和Control组之间的体重增量有明显统计学意义(P<0.01)。术后SG组空腹血糖浓度较其它3组明显降低(P<0.05),SG组术后第2周OGTT曲线下面积(AUC)较其术前减少约28.1%(P<0.01),相对于其它3组有显著性的差异(P<0.05)。术后第6周的ITT显示SG组胰岛素敏感性较sham-SG组明显改善,血糖水平变化明显降低。实验期间,与sham-SG组相比,SG组胰岛素浓度无明显变化(P>0.05), Ghrelin浓度明显下降(P<0.01), GLP-1浓度上升(P<0.01)。结论：SG降糖效果确切,能够独立于体重的变化而直接有效地降低血糖。术后Ghrelin浓度下降、GLP-1浓度升高可能是SG降糖的主要机制。目的：建立胃袖状切除附加改良空回肠旁路的GK大鼠模型并对其分析。方法：将27只GK大鼠随机分为改良胃袖状切术(MSG)组、假手术(sham-MSG)组、饮食配对组(PF)组和空白对照(Controls)组。动态观察手术前和手术后16周体重、空腹血糖、口服葡萄糖耐量试验(OGTT)、胰岛素浓度、胰岛素抵抗指数(HOMA-IR)及其体内血脂水平的变化。结果：从手术后第4周起MSG与sham-MSG和PF组的体重增量有明显统计学差异(P<0.01)。MSG组空腹血糖浓度较其它3组明显降低。术后第2周MSG组的OGTT曲线下面积(AUC)较术前减少约38.9%(P<0.01),而在sham-MSG和PF组却无以上明显变化。实验期间,MSG组胰岛素敏感性及其分泌量明显改善,而在sham-MSG组却无以上明显变化。与PF组和sham-MSG组相比,MSG组在术后的血脂浓度得到明显改善。这些结果显示后肠在血糖调节中可能起到了重要的作用。结论：MSG独立于体重和进食量的变化直接控制GK大鼠体内血糖水平,为2型糖尿病治疗机制的研究提供了一种稳定、持久的降糖手术模型。目的：研究改良袖状胃切除术的降糖作用,并对其降糖机制进行初步探讨。方法：54只GK大鼠和6只Wistar大鼠随机分为改良袖状胃切除(modified sleeve gastrectomy, MSG)组,延迟-改良袖状胃切除(delayed-modified sleeve gastrectomy,MSG)组,袖状胃切除(sleeve gastrectomy, SG)组,对应MSG组的假手术(sham-MSG)组,对应SG组的假手术(sham-SG)组,药物治疗(罗格列酮,rosiglitazone, RSG)组,限制饮食(food restriction, FR)组；空白对照(Controls)组;Wistar大鼠构建为(Wistar MSG, WMSG)组。动态观察手术前后16周中各组大鼠对应的检测项目：体重、空腹血糖、口服葡萄糖耐量试验(OGTT)、胰岛素耐量试验(ITT)；胰岛素、Ghrelin、GLP-1和GIP浓度的变化。在术后第16周,组织中insulin、Ghrelin、GLP-1和GIP(胰腺、末端回肠、十二指肠和下丘脑)对应基因表达的变化水平及其手术后胰腺和末端回肠等组织的形态学变化。结果：手术后,MSG组对葡萄糖耐量较其它各组的GK大鼠明显改善。术后第2周,MSG组行OGTT后的曲线下面积较术前减少38.9%(P<0.001),较SG减少23.9%(P=0.007),而sham-MSG/SG、Controls和FR组都没有以上的变化发生。MSG组术后2周对葡萄糖耐量的改善程度较该组术前(SG术后8周)明显。MSG组行ITT后血糖水平变化较RSG改善明显。术后,MSG组空腹血浆Ghrelin水平较假手术组明显改善(P<0.001),MSG组进食葡萄糖后血浆GLP-1水平较SG和假手术组明显升高(P<0.001)。术后MSG组胰岛素水平较SG和假手术组明显改善(P<0.05)。术后16周,MSG组织中的胰岛素和GLP-1基因的表达水平明显上升,并且MSG组胰岛形态明显改善,阳性B细胞量和胰岛内成熟腺泡的电子密度都明显增加,胰岛细胞水肿现象明显缓解。这些结果显示后肠在血糖调节中起到了重要的作用。结论：MSG是一种相对稳定的、独立与体重和进食量的变化外直接改善血糖并改善胰岛素敏感性的一种手术方式；MSG进一步证实了2型糖尿病的病因可能与体内多种激素分泌的失衡有关,重新调节体内胰岛素内分泌轴的平衡可能是治疗糖尿病的有效方法。更多还原

【Abstract】 PartⅠEstablishment of sleeve gastrectomy in Goto-Kakizaki ratsObjective To establish sleeve gastrectomy (SG) model in the nonobese type 2 diabetic model-Goto Kakizaki (GK) rats, and to investigate that SG effects on blood glucose control.Methods Twenty three GK rats were randomly divided into the sleeve gastrectomy (SG), sham-sleeve gastrectomy (sham-SG) and pair food (PF) groups. Body weight, food intake, fasting glecmia, oral glucose tolerance test (OGTT), insulin tolerance test (ITT) and fasting plasma insulin concentration were measured in the special time of throughout the study.Results The succeeding rate of SG model is 100%. There were significant difference changes of body weight gain after the 4th operation (P< 0.01), but the fasting glycemia of SG rats was significantly improvance than PF and sham-SG groups. SG strikingly improved glucose tolerance, two weeks after surgery, the area under the blood glucose concentration curve (AUC) of SG decreased by about 28.1% compared to pre operation (P< 0.01), the AUC of SG reduced about 21% compared with PF (P< 0.01). Insulin tolerance test (ITT) and insulin resistance index (IRI) of SG rats were more significant improvement than sham-SG and PF animals.Conclusions SG is a relatively stable hypoglycemic surgical model and SG can directly controls type 2 diabetes and not secondarily to weight loss.PartⅡResearch hypoglycemic effect and mechanism of sleeve gastrectomyObjective Investigate hypoglycemic effect and its mechanism of sleeve gastrectomy (SG).Methods 30 GK rats were randomly divided into sleeve gastrectomy (SG), sham-sleeve gastrectomy (sham-SG), pair-fed (PF) and controls (Controls). Before and after surgery, we dynamically observed on changes of weight, fasting glucose, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), fasting plasma insulin, fasting plasma ghrelin and plasma GLP-1 in 24 weeks.Results From the 4th week of post-operation, the weight gain changes of SG and PF had significantly decreased compared with sham-SG and Controls group (P< 0.01). From the 2nd week post-operation, Fasting glucose concentration of SG were lower than sham-SG, PF and Controls group (P< 0.05), and the OGTT of SG rats was better improved than pre-operation and the other 3 groups. Two weeks after operation, SG was better improved glucose tolerance than pre-operation, the area under the blood glucose concentration curve (AUC) decreased by about 28.1%(P< 0.01), these effects were not seen in the sham-SG and PF animals despite similar change of weight changes and food intake. The 6th week after surgery, the results of ITT shows that insulin sensitivity of SG was obviously improvement and significantly lowered blood glucose levels compared with sham-SG group. Throughout the experiment period, we compared the hormone changes of SG and sham-SG animals, the results showed that there had no clear changes of insulin concentration (P> 0.05). Compared to sham-SG, SG significantly decreased the concentration of ghrelin (P< 0.01) and slightly raised the concentration of GLP-1 (P <0.01).Conclusions The hypoglycemic effects of SG are definite. Post-operation, SG can directly control blood glucose and not secondarily to weight loss and the decreased Ghrelin and slightly raised GLP-1 may be the major mechanism of hypoglycemic by SG.PartⅢEstablishment of modified sleeve gastrectomy in Goto-Kakizaki ratsObjective Creation and analysis of the model of modified sleeve gastrectomy by non-obese diabetic Goto-kakizaki (GK) rats.Methods 27 GK rats were randomly divided into MSG, sham-MSG, pair-fed (PF) and controls (Controls) group. Before and after operation, the changes of weight, food intake, fasting glucose, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), fasting plasma Insulin concentration, HOMA-IR and blood lipids changes were dynamically observed in 16 weeks.Results From the 4th week of post-operation, the weight gain changes of MSG had significantly decreased compared with sham-MSG and PF group (P< 0.01). Fasting glucose concentration of MSG were lower than sham-MSG, PF and Controls group, and the OGTT of MSG rats was better improved than pre-operation and the other 3 groups. Two weeks after operation, compared to pre-operation, MSG was obviously improved glucose tolerance, the area under the blood glucose concentration curve (AUC) decreased by about 38.9%(P< 0.01), these effects were not seen in the sham-MSG and PF animals despite similar weight changes and food intake. In this experiment, the insulin sensitivity and secretion of MSG were obviously improvement; these effects were not seen in the sham-MSG animals. Compared to PF and sham-MSG, the blood lipids concentration levels of MSG were significantly improvement. These results show that hindgut maybe plays a key role in the hypoglycemic effect.Conclusions MSG provides a stable, long-lasting hypoglycemic surgery model to research the mechanism of treating type 2 diabetes and is directly and effectively linked to improve the metabolism of blood glucose and blood lipids in GK rats, independently of weight loss and caloric intake.PartⅣResearch hypoglycemic effect and mechanism of modified sleeve gastrectomyObjective To study the hypoglycemic effect and its mechanism of modified sleeve gastrectomy (MSG).Methods 54 GK rats and 6 Wistar rats were randomly divided into modified sleeve gastrectomy (MSG), delayed-modified sleeve gastrectomy (D-MSG), sleeve gastrectomy (SG), sham-modified sleeve gastrectomy (sham-MSG), sham-sleeve gastrectomy (sham-SG), rosiglitazone (RSG), food restriction (FR), controls (Controls) and Wistar MSG (WMSG). Before and after surgery, each group corresponding changes were dynamically observed in 16 weeks:weight, fasting blood glucose, oral glucose tolerance (OGTT), insulin tolerance test (ITT), plasma fasting insulin, Ghrelin, GIP and plasma GLP-1. At 16th week after surgery, the gene expression of Ghrelin, GLP-1, GIP and insulin were measured in the tissues (pancreatic islets, distal ileum, duodenum and hypothalamus), and the morphological characteristics of pancreatic islets and distal ileum were investigated.Results After operation, MSG had significantly improved glucose tolerance compared with the other groups. At the 2nd week after surgery, MSG was better improved glucose tolerance than pre-operation, the area under the blood glucose concentration curve (AUC) decreased by about 38.9%(P< 0.001), the AUC of MSG reduced about 23.9% compare with SG (P= 0.007). These effects were not seen in the sham-MSG/SG and FR animals despite similar change of weight changes and less food intake. At 2nd week post-operation, D-MSG had obviously improvement compared with the pre-operation (at the 8 weeks after SG). At the 4th week after surgery, the ITT of MSG was obviously improved compared with RSG. After surgery, MSG had significantly decreased Ghrelin level (P< 0.001), increased GLP-1 level (P< 0.001) and significantly enhanced gene expression of GLP-1 and insulin gene. Immunohistochemistry examination revealed distinctly improved expression of positiveβ-cell and electron microscopy presented a remarkable increasing numbers of secretary granules in pancreatic islets of MSG, the cell edema were clear relieved. While SG and sham surgery groups had no obvious changes which were mentioned above. These results suggesting that hindgut played a key role in the hypoglycemic effect.Conclusion MSG is directly linked to the reduction in glucose levels and improvement in insulin sensitivity in GK rats, independently of weight loss and caloric intake. MSG further confirmed that the etiology of type 2 diabetes may be related to gastrointestinal hormones imbalance, re-adjust the balance of insulin endocrine axis may be an effective way to treat diabetes.更多还原