AQP-4 mRNA在新生鼠缺氧缺血损伤脑组织的表达及与脑水肿的关系探讨

目的观察水通道蛋白4 mRNA(aquaporin-4,AQP-4 mRNA)在新生鼠缺氧缺血损伤脑组织的表达,探讨其变化及与脑水肿发生的可能关系。方法健康7日龄SD大鼠共240只,随机分为对照组120只和缺氧缺血性脑损伤模型组(HIBD组)120只。HIBD组经右侧颈总动脉结扎后,吸入8%O21h,建立HIBD模型。对照组仅行假手术,不予颈总动脉结扎和缺氧。两组均于HIBD模型制成后0、6、24、48h和72h分别处死动物(各时间点动物24只),进行脑含水量观察,RealtimePCR检测脑组织AQP-4 mRNA表达。结果HIBD组6、24、48h和72h脑组织含水量均较对照组增加,差异有统计学意义(P<0.05);与对照组比较,HIBD组脑组织AQP-4 mRNA表达在48h内呈下降趋势,72h出现恢复,但仍低于对照组(P<0.05)。结论AQP-4 mRNA在脑组织表达下降可能与脑水肿的发生有关,我们推测AQP-4可能参与了HIBD时脑水肿的调节机制。

The expression and significance of AQP-4 mRNA in the brain tissues of rats with hypoxic-ischemic brain damage

Objective To study the expression of aquaporin-4 (AQP-4) mRNA and its dynamic relationship with cerebral edema in the brain tissue of newborn rats with hypoxic-ischemic brain damage (HIBD). Methods Two hundred and forty 7days old SD rats were selected and randomly divided into control group and experimental group. The rats in experimental group were treated with ligation of right carotid artery and then were kept in boxes filled with 8% oxygen and 92% nitrogen for an hour to establish HIBD models. The rats in control group received sham procedure. The rats were divided into 5 groups according to the time they were sacrificed after establishment of HIBD or sham operation, 0, 6, 24, 48 and 72 h. Real-time PCR was used to detect the expression of AQP-4 mRNA and dry weight method to measure water content in brain tissue of rats. Results Compared with control groups, the water content of brain tissue was increased markedly in HIBD groups after 6 h of hypoxic and ischemic exposure, and it was getting worse with the prolongation of time (P<0.05). The expressions of AQP-4 mRNA in neonatal brain tissue were decreased significantly in HIBD groups during the period of 6 h to 72 h after establishment of HIBD than in control group (P<0.05). Conclusions It is likely that the decreased expression of AQP-4 mRNA is associated with cerebral edema in rats with HIBD and AQP-4 may play an important role in the regulatory mechanisms of cerebral edema.