肿瘤坏死因子一α抑制剂英夫利西单抗通过降低吲哚胺2,3-双加氧酶活性减轻短暂性大脑中动脉闭塞小鼠的认知损害

Tumor necrosis factor-α inhibitor infliximab alleviates cognitive impairment in mice with transient middle cerebral artery occlusion by decreasing indoleamine 2,3-dioxygenase activity

目的 探讨肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)在卒中后认知损害(post-stroke cognitive impairment,PSCI)中作用及其机制.方法 60只9~11周龄C57BL/6J雄性小鼠随机分为假手术组、PSCI组和英夫利西单抗组,采用大脑中动脉闭塞法建立PSCI模型.英夫利西单抗组给予英夫利西单抗腹腔注射(10 mg/kg,2次/周),PSCI组注射等体积生理盐水.利用水迷宫和避暗实验评价认知损害.蛋白质印迹分析检测海马TNF-α 和白细胞介素-18(interleukin-18,IL-18)含量.通过高效液相色谱技术检测海马犬尿氨酸及色氨酸水平,评估吲哚胺2,3-双加氧酶(indoleamine 2,3-dioxygenase,IDO)活性(犬尿氨酸/色氨酸比值)变化.结果 Morris水迷宫实验表明,与假手术组相比,PSCI组小鼠逃避潜伏期显著延长,目标象限停留时间显著缩短,穿越目标象限次数显著减少(P均<0.05);英夫利西单抗组较PSCI组逃避潜伏期显著缩短,目标象限停留时间显著延长,穿越次数显著增多(P均<0.05).避暗实验结果提示,PSCI组小鼠潜伏期显著缩短而错误次数显著增多(P均<0.05);英夫利西单抗组较PSCI组潜伏期显著延长,错误次数显著减少(P均<0.05).与假手术组相比,PSCI组小鼠海马组织TNF-α和IL-18水平显著增高(P均<0.05),犬尿氨酸/色氨酸比值显著增高(P<0.05);英夫利西单抗组海马TNF-α 水平以及犬尿氨酸/色氨酸比值均较PSCI组显著降低(P均<0.05).结论 TNF-α 抑制剂英夫利西单抗能通过降低IDO活性减轻小鼠PSCI.

Objective To investigate the role and its mechanism of tumor necrosis factor-α (TNF-α) in post-stroke cognitive impairment (PSCI). Methods Sixty male C57BL/6J mice aged 9-11 weeks were randomly divided into sham operation group, PSCI group, and infliximab group. A PSCI model was induced by middle cerebral artery occlusion. The infliximab group was given infliximab intraperitoneally (10 mg/kg, twice a week), and the PSCI group was injected with an equal volume of normal saline. Water maze and light-dark transition tests were used to evaluate cognitive impairment. Western blot analysis was used to detect hippocampal TNF-α and interleukin-18 ( IL-18 ). The levels of kynurenine and tryptophan in hippocampus were measured by high performance liquid chromatography (HPLC), and the changes of indoleamine 2,3-dioxygenase (IDO) activity (the ratio of kynurenine to tryptophan) were evaluated. Results Morris water maze experiment shows that the escape latency of mice was significantly prolonged in the PSCI group, the target quadrant stay time was significantly shortened, and the number of crossing target quadrants was significantly reduced compared with the sham operation group (all P < 0. 05). The escape latency of the infliximab group was significantly shorter than that of the PSCI group, the target quadrant stay time was significantly prolonged, and the number of crossings increased significantly ( all P < 0. 05 ). Light-dark transition test shows that the latency of the mice was significantly shortened and the number of errors was significantly increased in the PSCI group (all P < 0. 05). The latency of the infliximab group was significantly prolonged compared with the PSCI group, and the number of errors was significantly reduced (all P < 0. 05). Compared with the sham operation group, the levels of TNF-α and IL-18 in the mouse hippocampus of the PSCI group were significantly increased (all P < 0. 05), and the kynurenine/tryptophan ratio was significantly increased (P < 0. 05); the level of TNF-α in hippocampus and the ratio of kynurenine/ tryptophan in the infliximab group were significantly lower than those in the PSCI group (all P < 0. 05). Conclusion TNF-α inhibitor infliximab can alleviate PSCI in mice by reducing IDO activity.