20-羟基蜕皮甾酮对大鼠全脑缺血再灌注后海马神经元损伤和炎症反应的影响

目的:观察20-羟基蜕皮甾酮对全脑缺血再灌注后SD大鼠海马神经元和认知功能的保护作用,并探讨其相关机制。方法:采用四血管闭塞法建立SD大鼠全脑缺血再灌注模型,脑电图和脑组织Nissl染色评估模型的可靠性。将实验动物分为假手术组,缺血再灌注组和缺血再灌注+20-羟基蜕皮甾酮组。TUNEL染色观察海马神经元凋亡,Morris水迷宫实验评价大鼠的认知功能,酶联免疫法测定缺血再灌注后3-24小时大鼠血清中白细胞介素-1β(IL-1β)和肿瘤坏死因子α(TNF-α)的浓度。结果:全脑缺血再灌注后大鼠海马神经元凋亡率从4.50±1.90%上升至72.90±8.40%(p0.01),给予20和40 mg/kg 20-羟基蜕皮甾酮干预,大鼠海马神经元凋亡率分别下降至51.40±8.60%(p0.05)和42.70±6.80%(p0.01)。与假手术组相比,全脑缺血再灌注后大鼠在Morris水迷宫定位航行试验中逃避潜伏期明显延长(p0.01),在空间探索试验中目标象限停留时间和穿越目标象限次数明显减少(p0.01),而20-羟基蜕皮甾酮显著抑制上述变化,改善大鼠的认知功能。缺血再灌注后3-24小时,大鼠血清中IL-1β和TNFα浓度较假手术组显著升高,20-羟基蜕皮甾酮能抑制上述各时间点大鼠血清中IL-1β和TNFα浓度的升高。结论:20-羟基蜕皮甾酮对全脑缺血再灌注后大鼠海马神经元和认知功能有显著保护作用,抑制缺血再灌注后的炎症反应是其保护机制之一。

Effects of 20-hydroxyecdysone on Hippocampal Neuronal Damage and Inflammatory Response after Global Cerebral Ischemia and Reperfusion in SD Rats

ABSTRACT Objective: To investigate the protective effects of 20-hydroxyecdysone on hippocampal neurons and cognitive function and the related mechanisms in SD rats after global cerebral ischemia and reperfusion. Methods: The global cerebral ischemia reperfusion model was established by four vessel occlusion method in SD rats. The reliability of the model was evaluated by EEG and Nissl staining of brain tissue. The experimental animals were divided into sham operation group, ischemia-reperfusion group and 20-hydroxyecdysone-treation after ischemia-reperfusion group. TUNEL staining was used to observe the apoptosis of hippocampal neurons. The cognitive function of rats was evaluated by Morris water maze test. The concentration of IL-1 and TNF in serum of rats at 3-24 hours after ischemia reperfusion was determined by enzyme-linked immunosorbent assay. Results: SD rats hippocampus neuron apoptosis rate was increased from 4.50±1.90% up to 72.90±8.40% after global cerebral ischemia reperfusion. After 20 and 40 mg/kg 20-hydroxyecdysone intervention, the apoptosis rate of rat hippocampal neurons decreased to 51.40 + 8.60% (P < 0.05) and 42.70 + 6.80% (P < 0.01). Compared with the sham operation group, the escape latency of rats in the Morris water maze navigation test was significantly prolonged (P < 0.01) and the time spent in the target quadrant time and the number of traversing target quadrant in the Morris water maze space exploration test are significantly reduced (P < 0.01). 20-hydroxyecdysone inhibited the above changes and improved the cognitive function of rats. The concentrations of IL-1 and TNF in serum of rats were significantly increased at 3-24 hours after ischemia reperfusion, which were inhibited by 20-hydroxyecdysone. Conclusion: 20-hydroxyecdysone protected hippocampal neurons and cognitive function in SD rats after global cerebral ischemia by inhibited the inflammatory response after global cerebral ischemia and reperfusion.