韦晗宁,
黄永成,
王敏,
张晓溪^,
桂林医学院 基础医学院，广西 桂林 541199

基金项目: 国家自然科学基金项目（81860155）


详细信息 作者简介: 韦晗宁（1973-），女，副教授。E-mail：hanningweigl@163.com




通讯作者: 张晓溪，副研究员。E-mail：mike_527@163.com 中图分类号: R392.32


摘要:目的通过观察脾脏切除对小鼠胰岛形态功能及肠道微生物的影响，探讨脾脏与肠道微生物及胰岛功能之间的内在联系。方法30只雄性KM小鼠随机分为3组，正常对照组（NC组，n=10），假手术组（Sham组，n=10）及脾切除组（SPX组，n=10）。其中NC组小鼠未做任何处理，Sham组腹壁切开轻微翻动脾脏后缝合，SPX组开腹进行切除全部脾脏后缝合。观察各组小鼠切脾后的状态及活动情况，切脾后定期测定体重、空腹血糖。切脾干预120天后进行口服糖耐量试验（OGTT），ELISA法检测血清胰岛素、C肽水平，HE染色观察小鼠胰腺、小肠组织病理变化。通过粪便16S rRNA测序检测小鼠肠道菌群结构分布。结果切除脾脏120天后，SPX组较NC、Sham两组小鼠体重明显增加（P＜0.01），2 h内血糖曲线下面积（AUC）显著增加（P＜0.01）。SPX组血清胰岛素显著高于NC组（P＜0.01）和Sham组（P＜0.01），C肽水平显著高于NC组（P＜0.01）和Sham组（P＜0.05）。SPX组小鼠胰岛数目减少，胰岛形态变化，周围炎症浸润明显；小肠组织出现淋巴细胞浸润。与NC组、Sham组相比，SPX组小鼠肝脏中TGF-β1蛋白表达水平上调（P＜0.01，P＜0.01），而TLR-4蛋白表达水平下调（P＜0.05，P＜0.01）。SPX组肠道微生物种群比例较NC组、Sham组有显著变化，其中厚壁菌门/拟杆菌门比值下降（P＜0.01）；瘤胃球菌科（P＜0.001）和拟杆菌S24-7科细菌（P＜0.01）显著增加；丛毛单胞菌科（P＜0.01）和普雷沃氏菌科（P＜0.001）细菌显著减少；未分类丛毛单胞菌属（P＜0.05）及未分类伯克氏菌属细菌（P＜0.001）数量显著降低；未分类梭杆菌属（P＜0.001）、未分类毛螺菌属（P＜0.01）、颤螺菌属细菌（P＜0.01）数量显著升高。结论脾切除后可能造成慢性炎症，机体免疫防御、免疫监视功能减弱，肠道、胰岛形态和功能异常，远期有发生2型糖尿病、肿瘤等疾病风险。
关键词: 脾切除/
胰岛形态功能/
肠道微生物/
糖尿病风险


Abstract:ObjectiveTo study the mechanisms of pancreatic endocrine function regulated by spleen.MethodsIn the current study, 30 male KM mice were randomly divided into 3 groups: normal control group (NC, n=10), sham operation group (Sham, n=10), and splenectomy group (SPX, n=10). In NC group, the mice did not receive any treatment. In Sham group, the spleen was slightly turned over after sham operation. In SPX group, splenectomy was performed through laparotomy. The status and activities of mice in each group were observed after splenectomy. Body weight and fasting blood glucose after splenectomy were regularly determined. After 120 days of splenectomy, the oral glucose tolerance test (OGTT) was performed. Serum insulin and C-peptide levels were determined by ELISA. And the pathological changes in pancreas and small intestine of the mice were reviewed. The structure distribution of the intestinal flora in mice was detected by 16S rRNA sequencing of feces.ResultsAfter 120 days of splenectomy, compared with other two groups, the weight of SPX mice increased significantly (P＜0.01), the area under the curve (AUC) in 2 h glucose treatment was significantly increased (P＜0.01). Serum insulin level was significantly higher than NC (P＜0.01) and Sham groups (P＜0.01), C-peptide level was also significantly higher than NC (P＜0.01) and Sham groups (P＜0.05). Histologic examination revealed that the number of pancreatic islets in SPX mice decreased, and the islet morphology changed with marked inflammatory infiltration in the surrounding tissue; the small intestinal demonstrated lymphocytic infiltration. Compared with NC and Sham groups, TGF-β1 was up-regulated (P＜0.01, P＜0.01), and TLR-4 down-regulated (P＜0.05, P＜0.01) in SPX group. The distribution of gut microbiota species in SPX group showed significant changes compared to NC and Sham groups, with a significant decrease in the ratio of Firmicutes/Bacteroidetes (P＜0.01), a significant increase of Ruminococcaceae (P＜0.01) and Bacteroidales S24-7 (P＜0.01), and a significant decrease of Comamonadaceae (P＜0.01) and Prevotellaceae (P＜0.001). In general, Unclassified Streptomonas (P＜0.05) and Unclassified Burkholderiales (P＜0.001) were decreased significantly, while Unclassified Clostridiales (P＜0.01), Unclassified Lachnospiraceae (P＜0.01), and Oscillospira (P＜0.01) were increased significantly.ConclusionThe immune defense and immune surveillance functions of the body are reduced after splenectomy. The abundance and proportion of intestinal microbial populations change significantly in SPX mice, leading to inflammation of the small intestine and pancreas, resulting in abnormal islet morphology and function, which might further induce insulin resistance and even increase diabetic risk.
Keywords:splenectomy/
morphology and function of islet/
gut microbiota/
diabetic risk

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