碱性成纤维细胞生长因子对小鼠创伤性脑损伤后周细胞的影响及其意义

Effects of basic fibroblast growth factor on pericytes in mice with traumatic brain injury

目的探讨小鼠创伤性脑损伤（TBI）后急性期碱性成纤维细胞生长因子（bFGF）对血脑屏障中周细胞的作用。方法选取90只C57BL／6小鼠，按随机数字表法分为假手术组（只开骨窗不损伤）、TBI组和给药组（TBI＋bFGF组），每组30只。采用皮质打击法建立中度TBI模型。造模24h后采用Garcia神经学评分评价神经功能变化。腹腔注射伊文思蓝行血脑屏障通透性检测。分离大脑皮层，用Western blot法检测周细胞血小板衍生长因子受体-β（PDGFR—β）、氨肽酶N（CD13）、结蛋白、神经胶质细胞2型硫酸软骨素糖蛋白（NG2）及内参甘油三磷酸脱氢酶（GAPDH）的变化。HE染色观察组织形态学变化，免疫荧光染色法检测PDGFR—β、CD13、细胞表面糖蛋白MUC18（CD146）的变化。结果TBI组Garcia神经学评分较假手术组明显下降（P〈0．01），TBI＋bFGF组神经学评分较TBI组明显增加（P〈0．05）。TBI组通透性较假手术组明显增加（P〈0．01），TBI＋bFGF组较TBI组通透性明显减少（P〈0．01）。Western blot结果显示TBI组PDGFR—β、CD13、结蛋白、NG2表达较假手术组明显下降（P均〈0．05），TBI＋bFGF组PDGFR—β、CD13、结蛋白、NG2表达较TBI组明显上升（P均〈0．05）。HE染色结果显示，与假手术组和TBI＋bFGF组比较，TBI组脑组织破坏严重，受压损伤深度变深，可见出血灶，血管结构消失。免疫荧光染色结果显示，TBI组PDGFR—β、CD13、CD146表达较假手术组明显下降（P均〈0．01），TBI＋bFGF组PDGFR—β、CD13、CD146表达较TBI组明显上升（P均〈0．05）。结论小鼠TBI后bFGF可以保护周细胞的相关蛋白，减少周细胞死亡，从而保护血脑屏障，减轻大脑皮层的损伤程度。

Objective To investigate the effects of basic fibroblast growth factor （bFGF） on perieytes in the blood brain barrier at acute stage after traumatic brain injury （TBI） in mice. Methods A total of 90 mice with a C57BL/6 background were randomly divided into sham group, TBI group, and TBI ＋ bFGF group, with 30 rats per group. The models of moderate TB1 were established using the controlled cortical impactor. After 24 hours, the changes of nerve function were evaluated by Garcia neurological score. Each mouse received an intraperitoueal injection of Evans blue dye for measuring the permeability of blood brain barrier. Western blot was used to test the related indices of pericytes after the cerebral cortex was quickly dissected： platelet-derived growth factor receptor beta （PDGFR-β）, aminopeptidase N （CD13）, desmin, neuroglioeyte 2 （NG2）, and glyceraldehyde-3-phosphate dehydrogenase （GAPDH）. Paraffin sections were prepared for HE staining and morphological changes were observed, hnnmnofluorescence assay was used to test the related indices of pericytes： PDGFR-β, CD13, and cell surface glycoprotein MUC18 （CD146）. Results Gareia neurological score revealed that the score in TBI group was significantly decreased compared with that in sham group （ P 〈 0.01 ）, but the score of TBI ＋ bFGF group was significantly increased compared with that of TBI group （ P 〈 0.05 ）. Permeability of blood brain barrier in TBI group was significantly increased compared with that in sham group （P 〈 0.01 ） , but in TBI ＋ bFGF group this parameter significantly reduced compared with that in TBI group （P 〈 0.01 ）. Western blot analysis revealed that the expressions of PDGFR-β, CDI3, desmin, NG2 proteins in TBI group were signifieantly decreased compared with those in sham group （P 〈0.05）, while the expressions of PDGFR-β, CD13, desmin, NG2 proteins in TBI ＋ bFGF group were significantly increased compared with those in TBI group （ P 〈 0. 05 ）. HE staining revealed injury of brain parenchyma in TBI group was the severest compared with both sham group and TBI ＋ bFGF group, hnmunofluorescence staining results revealed that the proteins expressions of PDGFR-β, CD13, and CD146 in TBI group were significantly decreased compared with those in sham group （ all P 〈 0.01 ） , and those in TBI ＋ bFGF group were signifieantly inereased eompared with those in TBI group （ all P 〈 0.05 ）. Conclusions bFGF can prevent pericyte death via protecting its proteins to conserve blood-brain barrier, bFGF ean also significantly ameliorate the injury of brain parenchyma.