Ke C, Poon W S, Ng H K, Pang J C, Chan Y
Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, PR China.
Neurosci Lett. 2001 Mar 23;301(1):21-4. doi: 10.1016/s0304-3940(01)01589-0.
Aquaporin-4 (AQP4) is the most abundant water channel in the rat brain. In this study, the distribution pattern and mRNA expression levels of AQP4 were examined in a severe traumatic brain injury model by immunohistochemistry and reverse transcription-polymerase chain reaction. Oedema formation and blood-brain barrier (BBB) integrity were assessed by wet-dry weight measurements and immunostaining of endogenous IgG respectively. In the oedematous contusional cortex with impaired BBB integrity, negative immunostaining of AQP4 and down-regulation of its mRNA level were identified (P<0.05) at 1 day post-injury, while in other oedematous regions of the injured brain where BBB was intact, there was no significant change in the AQP4 expression level. This heterogeneous pattern of AQP4 responses can be interpreted as follows: focal brain injury (such as a contusion) with impaired BBB resulting in vasogenic oedema is associated with reduction of AQP4 expression, whereas, in cytotoxic oedema, associated with diffuse brain injury with intact BBB, changes in AQP4 expression are not significant. This study provides basic information for investigating new treatments for traumatic brain oedema.
水通道蛋白4（AQP4）是大鼠脑中含量最丰富的水通道。在本研究中，通过免疫组织化学和逆转录聚合酶链反应，在重度创伤性脑损伤模型中检测了AQP4的分布模式和mRNA表达水平。分别通过干湿重测量和内源性IgG免疫染色评估水肿形成和血脑屏障（BBB）完整性。在血脑屏障完整性受损的水肿性挫伤皮层中，伤后1天AQP4免疫染色呈阴性，其mRNA水平下调（P<0.05），而在血脑屏障完整的损伤脑的其他水肿区域，AQP4表达水平无显著变化。AQP4反应的这种异质性模式可解释如下：血脑屏障受损导致血管源性水肿的局灶性脑损伤（如挫伤）与AQP4表达降低有关，而在与血脑屏障完整的弥漫性脑损伤相关的细胞毒性水肿中，AQP4表达变化不显著。本研究为研究创伤性脑水肿的新治疗方法提供了基础信息。
