BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intes...BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.展开更多
目的观察高糖刺激的大鼠肾小球系膜细胞基质金属蛋白酶-2(MMP-2)及其组织抑制物-2(TIMP-2)、膜型基质金属蛋白酶-1(MT1-MMP)和结缔组织生长因子(CTGF)的动态变化以探讨糖尿病肾病(DN)的发病机制。方法体外培养的大鼠HBZY-1肾小球系膜细...目的观察高糖刺激的大鼠肾小球系膜细胞基质金属蛋白酶-2(MMP-2)及其组织抑制物-2(TIMP-2)、膜型基质金属蛋白酶-1(MT1-MMP)和结缔组织生长因子(CTGF)的动态变化以探讨糖尿病肾病(DN)的发病机制。方法体外培养的大鼠HBZY-1肾小球系膜细胞分为低糖(5.5mmol/L葡萄糖)组、高糖(30mmol/L葡萄糖)组和渗透压对照(5.5mmol/L葡萄糖+24.5mmol/L甘露醇)组,24、48、72、96h后采用RT-PCR及Western blotting法分别检测MMP-2、TIMP-2、MT1-MMP及CTGF的mRNA及蛋白表达情况,酶联免疫吸附法(ELISA)检测培养上清中Ⅳ型胶原的含量。结果 Western blotting结果显示,与低糖组相比,高糖组MMP-2的表达在24h时略有升高,较低糖组增加10%±4%(P<0.05),至48h时则较低糖组减少42%±2%,其后随时间延长表达持续降低,至96h时较低糖组减少78%±2%;MT1-MMP表达在24h开始下降并随时间呈下降趋势,与低糖组相比较,在刺激的24h,高糖组MT1-MMP表达下降了29%±3%,随后持续下降,至96h则下降了78%±9%(P<0.01)。高糖组各时间点TIMP-2和CTGF表达均较低糖组增高,其中CTGF的表达在高糖刺激的24h即显著增高,为低糖组的201%±24%,随后持续增高,至培养96h为低糖组的484%±51%(P<0.01);TIMP-2的表达在24h时较低糖组增加55%±3%,且随时间延长呈增高趋势(P<0.01)。MMP-2、TIMP-2、MT1-MMP和CTGF的mRNA表达与相应蛋白的表达趋势基本一致。与低糖组相比,高糖组细胞上清中的Ⅳ型胶原于24h即有增加,且持续增高至96h(P<0.05)。低糖组和渗透压对照组组内、组间的各指标差异均无统计学意义。结论尽管高糖刺激早期可小幅诱导MMP-2的表达增强,但长期高糖刺激则可抑制MMP-2和MT1-MMP的表达及活化,同时促进系膜细胞TIMP-2和CTGF的表达。DN中肾小球细胞外基质的积聚可能是由于上述细胞因子和蛋白酶引起细胞外基质代谢失衡所致。展开更多
基金European Union and the Hungarian Government in the framework,No.EFOP-3.6.1-16-2016-00008Hungarian NKFIH fund project,No.FK131789(to Bódi N)+1 种基金János Bolyai Research Scholarship of the Hungarian Academy of Sciences(to Bódi N)and New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research,Development and Innovation Fund,No.ÚNKP-20-5(to Bódi N).
文摘BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.
文摘目的观察高糖刺激的大鼠肾小球系膜细胞基质金属蛋白酶-2(MMP-2)及其组织抑制物-2(TIMP-2)、膜型基质金属蛋白酶-1(MT1-MMP)和结缔组织生长因子(CTGF)的动态变化以探讨糖尿病肾病(DN)的发病机制。方法体外培养的大鼠HBZY-1肾小球系膜细胞分为低糖(5.5mmol/L葡萄糖)组、高糖(30mmol/L葡萄糖)组和渗透压对照(5.5mmol/L葡萄糖+24.5mmol/L甘露醇)组,24、48、72、96h后采用RT-PCR及Western blotting法分别检测MMP-2、TIMP-2、MT1-MMP及CTGF的mRNA及蛋白表达情况,酶联免疫吸附法(ELISA)检测培养上清中Ⅳ型胶原的含量。结果 Western blotting结果显示,与低糖组相比,高糖组MMP-2的表达在24h时略有升高,较低糖组增加10%±4%(P<0.05),至48h时则较低糖组减少42%±2%,其后随时间延长表达持续降低,至96h时较低糖组减少78%±2%;MT1-MMP表达在24h开始下降并随时间呈下降趋势,与低糖组相比较,在刺激的24h,高糖组MT1-MMP表达下降了29%±3%,随后持续下降,至96h则下降了78%±9%(P<0.01)。高糖组各时间点TIMP-2和CTGF表达均较低糖组增高,其中CTGF的表达在高糖刺激的24h即显著增高,为低糖组的201%±24%,随后持续增高,至培养96h为低糖组的484%±51%(P<0.01);TIMP-2的表达在24h时较低糖组增加55%±3%,且随时间延长呈增高趋势(P<0.01)。MMP-2、TIMP-2、MT1-MMP和CTGF的mRNA表达与相应蛋白的表达趋势基本一致。与低糖组相比,高糖组细胞上清中的Ⅳ型胶原于24h即有增加,且持续增高至96h(P<0.05)。低糖组和渗透压对照组组内、组间的各指标差异均无统计学意义。结论尽管高糖刺激早期可小幅诱导MMP-2的表达增强,但长期高糖刺激则可抑制MMP-2和MT1-MMP的表达及活化,同时促进系膜细胞TIMP-2和CTGF的表达。DN中肾小球细胞外基质的积聚可能是由于上述细胞因子和蛋白酶引起细胞外基质代谢失衡所致。
