睡眠碎片化对大鼠血管性认知障碍的影响及其与中枢炎症和氧化应激的关系

Effects of sleep fragmentation on vascular cognitive impairment and relationship with central inflammation and oxidative stress in rats

目的评价睡眠碎片化对大鼠血管性认知障碍的影响及其中枢炎症和氧化应激的关系。方法雄性SD大鼠48只,8~10周龄,体重210~240 g,采用随机数字表法分为4组(n=12):假手术组(Sham组)、假手术+睡眠碎片化组(Sham+SF组)、血管性认知障碍组(VCI组)和血管性认知障碍+睡眠碎片化组(VCI+SF组)。采用结扎双侧颈总动脉的方法制备大鼠血管性认知障碍模型。VCI+SF组和Sham+SF组于血管性认知障碍模型建立后第26天开始建立睡眠碎片化模型,第29天行条件性恐惧实验和旷场实验。条件性恐惧实验结束后,采用ELISA法检测海马TNF-α、IL-6含量,微板法检测海马SOD、谷胱甘肽过氧化物酶(GSH-Px)、MDA及铁含量,Western blot法检测NF-κB、caspase-3及谷胱甘肽过氧化物酶4(GPX4)表达水平。结果与Sham组相比,VCI组穿越格数、站立次数及僵直时间百分比降低,海马SOD及GSH-Px含量降低,MDA、IL-6、TNF-α及铁含量升高,NF-κB、caspase-3表达上调,GPX4表达下调(P<0.05);与Sham+SF组和VCI组相比,VCI+SF组穿越格数、站立次数及僵直时间百分比降低,海马SOD及GSH-Px含量降低,MDA、IL-6、TNF-α及铁含量升高,NF-κB、caspase-3表达上调,GPX4表达下调(P<0.05)。结论睡眠碎片化可加重大鼠血管性认知障碍,机制可能与诱导中枢炎症和氧化应激,导致海马神经细胞凋亡及铁死亡增加有关。

Objective To evaluate the effects of sleep fragmentation on vascular cognitive impairment(VCI)and the relationship with central inflammation and oxidative stress in rats.Methods Forty-eight male Sprague-Dawley rats,aged 8-10 weeks,weighing 210-240 g,were divided into 4 groups(n=12 each)by a random number table method:sham operation group(group Sham),sham operation+sleep fragmentation group(group Sham+SF),group VCI and VCI+sleep fragmentation group(group VCI+SF).VCI was induced by ligating bilateral common carotid arteries of anesthetized rats.In VCI+SF and Sham+SF groups,the sleep fragmentation model was established starting from day 26 after inducing VCI,and the contextual fear conditioning test and open field test were performed on day 29.After the end of the contextual fear conditioning test,the contents of tumor necrosis factor-alpha(TNF-α)and interleukin-1beta(IL-6)were determined by enzyme-linked immunosorbent assay,the hippocampal superoxide dismutase(SOD),glutathione peroxidase(GSH-PX),malondialdehyde(MDA)and iron contents were measured using microplate method,and the expression of nuclear factor-kappa B(NF-κB),caspase-3 and glutathione peroxidase 4(GPX4)was determined using Western blot.Results Compared with group Sham,the number of crossing lattices and standing on back legs and percentage of time spent freezing were significantly decreased,the contents of SOD and GSH-Px were decreased,the contents of MDA,IL-6,TNF-αand iron were increased,the expression of NF-κB and caspase-3 was up-regulated,and the expression of GPX4 was down-regulated in group VCI(P<0.05).Compared with Sham+SF and VCI groups,the number of crossing lattices and standing on back legs and percentage of time spent freezing were significantly decreased,the contents of SOD and GSH-Px were decreased,the contents of MDA,IL-6,TNF-αand iron were increased,the expression of NF-κB and caspase-3 was up-regulated,and the expression of GPX4 was down-regulated in group VCI+SF(P<0.05).Conclusion Sleep fragmentation can aggravate VCI,and the mechanism may be related to the induction of central inflammation and oxidative stress,which leads to increased apoptosis and ferroptosis in hippocampal neurons of rats.