Department of Neurosurgery, The Affiliated Union Hospital of Fujian Medical University, Fuzhou, Fujian, China.
Neurochem Res. 2010 Aug;35(8):1147-55. doi: 10.1007/s11064-010-0167-6. Epub 2010 Apr 13.
Toll-like receptors (TLRs) are considered to mediate the inflammatory reaction, which are involved in the pathophysiological processes of cerebral ischemia injury. To elucidate the possible role of inflammatory reaction and TLR2/4 signaling pathway in cerebral ischemia, in the present study, we explored the spatio-temporal distribution of inflammatory reaction, and further investigated the time-course expression of TLR2/4 and the downstream effector molecules after focal cerebral ischemia in rats. Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (pMCAO) for 6, 12, 24, 48 and 72 h. Neurological deficit, cerebral infarction and neutrophil infiltration were measured at different time points following pMCAO. Expression of TLR2/4 were examined by immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Nuclear factor-kappaB (NF-kappaB) and cyclooxygenase-2 (COX-2) were determined by western blot. Serum content of tumor necrosis factor-alpha (TNF-alpha) was detected by enzyme-linked immunosorbent assay (ELISA). Experimental results showed that pMCAO caused an increase of neutrophil infiltration in infarcted brain tissue, with a peaked activity at 24 h of ischemia. The inflammatory molecules including TLR2, TLR4, NF-kappaB, COX-2 and TNF-alpha were significantly increased after pMCAO, especially during 12-24 h of ischemia, which were correlated with pMCAO-induced brain injury and cerebral inflammation. Our studies suggested that TLR2/4 signaling pathway likely aggravated ischemic brain injury through mediating the inflammatory reaction. TLR2/4 signaling pathway may be a promising therapeutic target for cerebral ischemia injury.
Toll 样受体（TLRs）被认为介导炎症反应，参与脑缺血损伤的病理生理过程。为了阐明炎症反应和 TLR2/4 信号通路在脑缺血中的可能作用，本研究探讨了炎症反应的时空分布，并进一步研究了大鼠局灶性脑缺血后 TLR2/4 及其下游效应分子的时间表达。Sprague-Dawley 大鼠行永久性大脑中动脉闭塞（pMCAO）6、12、24、48 和 72 h。pMCAO 后不同时间点测定神经功能缺损、脑梗死和中性粒细胞浸润。用免疫组织化学、逆转录-聚合酶链反应（RT-PCR）和 Western blot 检测 TLR2/4 的表达。用 Western blot 测定核因子-kappaB（NF-kappaB）和环氧化酶-2（COX-2）。用酶联免疫吸附试验（ELISA）测定血清肿瘤坏死因子-α（TNF-α）含量。实验结果表明，pMCAO 导致梗死脑组织中性粒细胞浸润增加，缺血 24 h 时活性最高。炎症分子如 TLR2、TLR4、NF-kappaB、COX-2 和 TNF-α 在 pMCAO 后明显增加，尤其是在缺血 12-24 h 时，与 pMCAO 诱导的脑损伤和脑炎症相关。本研究提示 TLR2/4 信号通路可能通过介导炎症反应加重缺血性脑损伤。TLR2/4 信号通路可能是脑缺血损伤的一个有前途的治疗靶点。
