METHODS: A total of 45 aged healthy male Sprague Dawley rats were divided into control group, sham group, and dexmedetomidine group. The open tibia fracture surgery rat model was established, and dexmedetomidine was intraperitoneally injected before operation. The cognitive function of aged rats was examined by Morris Water-Maze Test, open field experiment, and passive avoidance memory test. The expression levels of IL-6, IL-1β, and TNF-α in the hippocampus were examined by enzyme-linked immunosorbent assay (ELISA).
RESULTS: The escape latency over 5 continuous days in the dexmedetomidine group was significantly shorter than that in the control group (all P<0.05). The number of swimming times and the percentage of swimming time in the dexmedetomidine group were significantly higher and longer than those in the control group (all P<0.05). Moreover, rats in the dexmedetomidine group exhibited shorter time of stay at the central square and higher number of standing times in comparison with the control group (all P<0.05). Compared with the control group, dexmedetomidine intraperitoneally injected before surgery significantly inhibited the expression levels of IL-6, IL-1β, and TNF-α in the hippocampus (all P<0.05).
CONCLUSIONS: Dexmedetomidine could significantly relieve the postoperative cognitive dysfunction in aged rats. The mechanism may be associated with the decreased inflammatory cytokines in the hippocampus.
方法:45只健康雄性SD大鼠分为对照组,假手术组,右美托咪定组。建立开放性胫骨骨折手术大鼠模型,术前腹腔注射右美托咪定。采用Morris水迷宫试验检测老年大鼠的认知功能,露天实验,和被动回避记忆测试。IL-6、IL-1β的表达水平,采用酶联免疫吸附试验(ELISA)检测海马组织中TNF-α的含量。
结果:右美托咪定组的逃避潜伏期连续5天明显短于对照组(均P<0.05)。右美托咪定组游泳次数和游泳时间百分比均显著高于对照组(均P<0.05)。此外,与对照组相比,右美托咪定组大鼠在中央广场的停留时间更短,站立次数更多(均P<0.05)。与对照组相比,术前腹腔注射右美托咪定显著抑制IL-6、IL-1β的表达,和TNF-α在海马区(均P<0.05)。
结论:右美托咪定能明显减轻老年大鼠术后认知功能障碍。其机制可能与海马中炎性细胞因子的减少有关。