Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio School of Medicine, TX 78229-3904, USA.
J Neurotrauma. 2013 Jan 1;30(1):55-66. doi: 10.1089/neu.2012.2488.
Traumatic brain injury (TBI) is the leading cause of death and disability in children and young adults. Neuroprotective agents that may promote repair or counteract damage after injury do not currently exist. We recently reported that stimulation of the purinergic receptor subtype P2Y(1)R using 2-methylthioladenosine 5' diphosphate (2MeSADP) significantly reduced cytotoxic edema induced by photothrombosis. Here, we tested whether P2Y(1)R stimulation was neuroprotective after TBI. A controlled closed head injury model was established for mice using a pneumatic impact device. Brains were harvested at 1, 3, or 7 days post-injury and assayed for morphological changes by immunocytochemistry, Western blot analysis, and wet/dry weight. Cerebral edema and expression of both aquaporin type 4 and glial fibrillary acidic protein were increased at all time points examined. Immunocytochemical measurements in both cortical and hippocampal slices also revealed significant neuronal swelling and reactive gliosis. Treatment of mice with 2MeSADP (100 μM) or MRS2365 (100 μM) 30 min after trauma significantly reduced all post-injury symptoms of TBI including edema, neuronal swelling, reactive gliosis, and AQ4 expression. The neuroprotective effect was lost in IP(3)R2-/- mice treated with 2MeSADP. Immunocytochemical labeling of brain slices confirmed that P2Y(1)R expression was defined to cortical and hippocampal astrocytes, but not neurons. Taken together, the data show that stimulation of astrocytic P2Y(1)Rs significantly reduces brain injury after acute trauma and is mediated by the IP(3)-signaling pathway. We suggest that enhancing astrocyte mitochondrial metabolism offers a promising neuroprotective strategy for a broad range of brain injuries.
创伤性脑损伤（TBI）是儿童和青年死亡和残疾的主要原因。目前不存在能够促进损伤后修复或对抗损伤的神经保护剂。我们最近报道，使用 2-甲基硫腺苷 5'二磷酸（2MeSADP）刺激嘌呤能受体亚型 P2Y（1）R 可显著减少光血栓形成诱导的细胞毒性水肿。在这里，我们测试了 P2Y（1）R 刺激在 TBI 后的神经保护作用。使用气动冲击装置为小鼠建立了受控的闭合性颅脑损伤模型。在损伤后 1、3 或 7 天收获大脑，并通过免疫细胞化学、Western blot 分析和干湿重法检测形态变化。在所有检查的时间点，脑水肿和水通道蛋白 4 型和神经胶质纤维酸性蛋白的表达均增加。皮质和海马切片的免疫细胞化学测量也显示出明显的神经元肿胀和反应性神经胶质增生。创伤后 30 分钟给予小鼠 2MeSADP（100 μM）或 MRS2365（100 μM）治疗可显著减轻 TBI 后的所有损伤症状，包括水肿、神经元肿胀、反应性神经胶质增生和 AQ4 表达。用 2MeSADP 处理的 IP（3）R2-/- 小鼠的神经保护作用丧失。脑切片的免疫细胞化学标记证实 P2Y（1）R 表达局限于皮质和海马星形胶质细胞，而不是神经元。总之，这些数据表明，星形胶质细胞 P2Y（1）R 的刺激可显著减轻急性创伤后的脑损伤，并且由 IP（3）信号通路介导。我们认为，增强星形胶质细胞线粒体代谢为广泛的脑损伤提供了一种有前途的神经保护策略。
