高原脑损伤血脑屏障变化的实验研究

目的：了解高原条件下颅脑损伤后血脑屏障（ｂｌｏｏｄ－ｂｒａｉｎｂａｒｉｅｒ，ＢＢＢ）变化的特点．方法：采用自由落体致伤法（致伤冲量为１２００ｇ·ｃｍ）造成颅脑损伤模型．ＢＢＢ变化的定性测定采用伊文氏蓝（ｅｖａｎｓｂｌｕｅ，ＥＢ）染色，利用荧光比色法测定组织中ＥＢ含量来定量代表ＢＢＢ通透性变化，同时电镜观察毛细血管的病理改变．结果：高原脑损伤后局部损伤区出现蓝染带较早且范围宽．脑组织中ＥＢ含量较平原损伤时含量有非常显著的增高．脑组织中毛细血管损伤严重，以基底膜破坏明显，其周围有大量的水肿液．结论：高原低压低氧条件可加重颅脑ＢＢＢ损伤破坏，通透性增高．

Study of Brain blood barrier Permeability Alteration in Experimental Brain Injury at High altitudes

Aim: In an attempt to study the brain blood barrier (BBB) permeability alteration in experimental brain injury at high altitudes. Methods: A model of local cerebral injury on rabbits was set up by a drop of 100gm weight at 12cm height hitting on the left epidura, in hypobaric hypoxia chamber at a simulated altitude of 4000m. BBB changes were assessed by means of the quantitative Evans Blue (EB) dye technique and electron microscopy. EB was used as a marker for serum albumin extravasation. The concentration of EB was measured in the peri injured brain tissue 1 hour after intravenous injection at 4, 8 ,12, 24 and 48 hours after brain injury. Results: The differences between high altitude injury group and plain injury group were highly significant ( P <0.001). The EB staining was also increased in the peri injured brain tissue of the high altitude injury animals. Electron microscopic observation revealed severe swelling of the capillary basal membrane and extracellcular edema at 4 hours, disruption of capillaries basal membrane at 8, 12 hours after brain injury of high altitude animals. Severe extracellcular edema and swelling of capillaries basal membrane occurred at 24 hours after brain injury of plain animals. Conclusion: The permeability of BBB gets worse after brain injury at high altitude and hypobaric hypoxia aggravates the disruption of BBB after brain injury.