Mao Juan, Yu Jia-lin, Fu Xue-mei, Wang Ting-hua
Sichuan Da Xue Xue Bao Yi Xue Ban. 2014 May;45(3):386-9, 409.
To investigate changes of Aquaporin-4 (AQP-4) and the relation of brain edema after different time of hypoxic ischemic brain damage (HIBD).
Healthy 3 day-old SD rats (n=60), were divided into Sham group (n=12), the hypoxic ischemic brain damage group (n=48). The rats were subjected to the ligation of right carotid artery (ischemia). After rewarming 30 min with mother, they were sent into a box full with 80 mL/L oxygen and 920 mL/L nitrogen (hypoxia) for 4 h, 8 h, 16 h, 24 h (n=12 respectively). The rats of sham group were subjected to exposure right carotid artery, but were not ligated. Rats of the HIBD group were sacrificed at 4 h, 8 h, 16 h, 24 h of hypoxic ischemic damage and rats of the sham group were sacrificed at 12 h after operation without hypoxic ischemic damage. Then brain water content from left and right hemisphere were investigated respetively to observe brain edema at different time of hypoxic ischemic brain damage, which was followed by the investigation of brain pathology through HE staining. Real time PCR was used to test the level of AQP-4 mRNA.
Water content of right brain increased significantly after 8 h, 16 h and 24 h hypoxic ischemic brain damage, compared with the sham group (P < 0.05). Under light microscopy, the size of neurons and glia cells increased gradually during 8-24 h following HIBD. Dissolved Neurons were obviously observed during 16-24 h of HIBD. Glia cells were scarcely distributed. The mRNA expression of AQP-4 in right hippocampus decreased significantly during 4-24h of HIBD by evaluated with real time PCR (P < 0.05), when compared with the sham group.
AQP-4 mRNA expression in hippocampus of neonatal rats with HIBD exhibited a significant decrease, which was associated with brain edema. The present findings indicated that AQP-4 may has a novel role in the brain edema in neonatal rats with HIBD.
探讨缺氧缺血性脑损伤（HIBD）不同时间后水通道蛋白4（AQP-4）的变化及其与脑水肿的关系。
将60只健康3日龄SD大鼠分为假手术组（n = 12）、缺氧缺血性脑损伤组（n = 48）。对大鼠进行右侧颈动脉结扎（缺血）。与母鼠复温30分钟后，将它们放入充满80 mL/L氧气和920 mL/L氮气的箱中（缺氧）4小时、8小时、16小时、24小时（每组n = 12）。假手术组大鼠暴露右侧颈动脉，但不结扎。HIBD组大鼠在缺氧缺血损伤4小时、8小时、16小时、24小时处死，假手术组大鼠在无缺氧缺血损伤的手术后12小时处死。然后分别检测左右半球的脑含水量，观察缺氧缺血性脑损伤不同时间的脑水肿情况，随后通过HE染色进行脑病理学检查。采用实时PCR检测AQP-4 mRNA水平。
与假手术组相比，缺氧缺血性脑损伤8小时、16小时和24小时后右侧脑含水量显著增加（P < 0.05）。光镜下，HIBD后8 - 24小时神经元和胶质细胞大小逐渐增加。HIBD 16 - 24小时可见明显的神经元溶解。胶质细胞分布稀少。实时PCR评估显示，与假手术组相比，HIBD 4 - 24小时右侧海马中AQP-4的mRNA表达显著降低（P < 0.05）。
HIBD新生大鼠海马中AQP-4 mRNA表达显著降低，且与脑水肿有关。本研究结果表明，AQP-4可能在HIBD新生大鼠脑水肿中具有新的作用。
