Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
Brain Res. 2011 Sep 15;1412:63-72. doi: 10.1016/j.brainres.2011.07.020. Epub 2011 Jul 18.
The mechanisms underlying the changes in blood-brain barrier (BBB) integrity in septic encephalopathy are poorly understood. The present study was designed to examine whether hyperbaric oxygen therapy (HBOT) influences the response of BBB to sepsis induced by cecal ligation and puncture (CLP) in rats. Cerebral cortical and hippocampal tissue levels of tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA) and glutathione (GSH) levels were measured. BBB permeability was functionally and structurally evaluated by determining extravasation of Evans blue (EB) and horseradish peroxidase (HRP) tracers, respectively. Immunohistochemistry and western blotting for occludin were performed. HBOT did not alter TNF-α levels in CLP operated rats while a significant decrease was noted when the therapy was subjected to intact rats. MDA levels in animals subjected to CLP plus HBOT were significantly decreased. In septic rats, the decreased GSH levels were significantly increased by HBOT. While HBOT attenuated the increased BBB permeability to EB in rats subjected to CLP (P<0.01), no macroscopic alteration was observed in the enhanced HRP extravasation. An increase in HRP extravasation was also observed by HBOT in intact animals. Occludin immunoreactivity and expression remained essentially unchanged in the brain capillaries of animals in all groups. Ultrastructurally, frequent vesicles containing HRP reaction products were observed in brain capillary endothelial cells of animals treated with CLP and/or HBOT. In conclusion, our results revealed that HBOT did not provide overall protective effects on the BBB integrity in septic conditions and even led to BBB disruption in intact animals.
在败血性脑病中，血脑屏障（BBB）完整性变化的机制尚不清楚。本研究旨在探讨高压氧治疗（HBOT）是否影响结扎和穿刺盲肠（CLP）诱导的大鼠败血症对 BBB 的反应。测量大脑皮质和海马组织中肿瘤坏死因子-α（TNF-α）、丙二醛（MDA）和谷胱甘肽（GSH）水平。通过测定 Evans 蓝（EB）和辣根过氧化物酶（HRP）示踪剂的渗出，分别从功能和结构上评估 BBB 通透性。进行 occludin 的免疫组织化学和蛋白质印迹分析。HBOT 并未改变 CLP 手术大鼠的 TNF-α水平，而在完整大鼠中则观察到显著降低。CLP 加 HBOT 处理的动物 MDA 水平显著降低。在败血症大鼠中，HBOT 显著增加了降低的 GSH 水平。HBOT 减轻了 CLP 大鼠 BBB 对 EB 的通透性增加（P<0.01），但对增强的 HRP 渗出没有观察到宏观改变。HBOT 还观察到完整动物中 HRP 渗出增加。在所有组的动物脑毛细血管中，occludin 免疫反应性和表达基本保持不变。超微结构观察到 CLP 和/或 HBOT 治疗的动物脑毛细血管内皮细胞中含有 HRP 反应产物的频繁小泡。总之，我们的结果表明，HBOT 并没有为败血症条件下的 BBB 完整性提供整体保护作用，甚至导致完整动物的 BBB 破坏。
