胰高血糖素样肽-1受体与紧密连接相关蛋白5在糖尿病大鼠脑微血管内皮的表达变化

Expression of glucagon like peptide-1 receptor and Claudin-5 in diabetic rat brain-microvascular endothelial cells

目的研究糖尿病大鼠脑微血管内皮细胞胰高血糖素样肽-1受体(GLP-1R)与紧密连接相关蛋白5(Claudin-5)的表达变化,初步探讨GLP-1在糖尿病大鼠脑微血管病变中的可能机制。方法 (1)8周龄雄性SD大鼠60只,随机分为高脂组(模型组,30只)与普通饲料组(对照组,30只),分别予以高脂饲料和普通饲料喂养8周。(2)8周后高脂组予以腹腔注射链脲佐菌素(STZ)30 g/kg,建立2型糖尿病(T2DM)大鼠模型。(3)成模4周后测定大鼠体重及空腹血糖变化。(4)处死各组大鼠,免疫组化和Western blot检测各组大鼠脑微血管内皮细胞上GLP-1R及Claudin-5蛋白表达情况。采用SPSS 13.0统计软件,计量资料用均数±标准差(x珋±s)表示,数据经正态检验后采用完全随机设计t检验。结果 (1)对照组大鼠体重由基础值(163.00±10.10)g增加至(331.10±17.40)g;模型组大鼠体重由基础值(165.00±12.10)g增加至(421.30±18.82)g,两组组内前后比较差异有统计学意义(t值分别为-100.935、-104.124,均P<0.05)。(2)模型组大鼠空腹血糖由基础值(5.370±0.552)mmol/L升高为4周时的(22.100±3.069)mmol/L,显著高于相应时间点对照组(t=29.190,P<0.05)。(3)成模8周后模型组大鼠海马皮质微血管内皮细胞上,GLP-1R表达弱于对照组(t=-31.787,P<0.05),且Claudin-5表达呈弱阳性,对照组大鼠Claudin-5呈强阳性表达(t=-24.288,P<0.05)。结论高糖可同时下调脑微血管内皮细胞上GLP-1R与Claudin-5蛋白的表达水平。

Objective To research the expression of glucagon like peptide-1 receptor （GLP-1R） and Claudin-5 on diabetic rat brain microvascular endothelial ceils, to discuss the possible mechanism of GLP-1 in diabetic rat brain microvascular lesions. Methods （ 1 ） 60 male SD rats （ 8 weeks old ） were randomly divided into high fat group （30 rats） and conventional feeding group （30 rats）. The rats were given high fat diet or normal diet 4 weeks. （2） After fed high fat diet 8 weeks, given the model group by intraperitoneal injection of streptozotoein （STZ） 30 mg/kg to establish type 2 diabetes （T2DM） model. （3） The change of each group of rats body weight and fasting blood glucose were measured after 4 weeks. （4） Immunohistochemistry and Western blot were adopted to detect GLP-1R and Claudin-5 expression on rat brain micro-vessel endothelial cell. Using SPSS 13.0 statistical software, the measurement data was represented by S ＋ s, after the normal examination, data using completely randomized design test. Results （ 1 ） The general feeding group rats weight increases from（ 163.00± 10. 10） g to （ 331.10 ±17.40） g;The T2DM model group increases from（ 165.00 ± 12. 10） g to（421.30± 18.82） g, there were significant differences between two groups（t = -100. 935, -104. 124,all P 〈0. 05）. （2）The model group rats fasting glucose of（5. 370 ＋0. 552）mmo]/L increased to（22. 100 ＋ 3. 069）mmol/L,was significantly higher than that in the corresponding time points, the normal control group（ t = 29. 190 ,P 〈 0. 05 ）. （ 3 ） The model group rats hippocampus cortex microvascular endothelial cells, GLP-1 R was weakly than that of the normal control group （t = - 31. 787, P 〈 0. 05 ）, the expression of Claudin-5 was weakly positive, normal control rats in the Claudin-5 group showed strong positive expression（ t = - 24. 288, P 〈 0. 05）. Conclusion High glucose can also cut the the expression of Claudin-5 and GLP-1R on miccrovascular endothelial cells.