磷酸二酯酶4抑制剂Ro20-1724对反复氯胺酮麻醉后幼年大鼠学习记忆障碍的改善作用

Phosphodiesterase 4 inhibitor Ro20-1724 improved learning and memory disorders in young rats after repeated ketamine anesthesia

目的探讨磷酸二酯酶4抑制剂Ro20-1724对反复氯胺酮麻醉后幼年大鼠学习记忆障碍的作用及对环磷酸腺苷(cAMP)/蛋白激酶A (PKA)-cAMP应答元件结合蛋白(CREB)-脑源性神经营养因子(BDNF)信号通路的调控。方法 6周龄SD大鼠80只,随机选取20只为正常对照组,剩余60只随机分为模型组和观察组(均n=30),每日给予氯胺酮(50 mg·kg^(-1))麻醉30 min后,模型组腹腔注射生理盐水2 mL,观察组给予Ro20-1724腹腔注射0.5 mg·kg^(-1),均连续注射7 d。Morris水迷宫观察各组大鼠的记忆能力。取大鼠海马组织,采用放射免疫法检测cAMP的含量, Western-blot法和荧光定量PCR来检测PKA、 CREB、 BDNF蛋白和m RNA的相对表达量。结果与正常对照组比较,模型组的水迷宫逃避潜伏期和第一次穿环时间延长(P <0.05),穿环次数减少(P <0.05), c AMP含量降低(P <0.05);与模型组相比,观察组的水迷宫逃避潜伏期缩短,第一次穿环时间减少且穿环次数增多(P <0.05),与正常对照组差异不显著(P> 0.05)。观察组的cAMP含量高于模型组(P <0.05),但是低于正常对照组(P <0.05)。观察组PKA、 CREB、 BDNF蛋白和m RNA相对表达量均高于模型组(P <0.05),与正常对照组差异不显著(P> 0.05)。结论 Ro20-1724可能通过调控cAMP/PKA-CREB-BDNF信号通路而改善由于反复氯胺酮麻醉造成的幼年大鼠学习记忆障碍。

AIM To explore the effect of phosphodiesterase 4 inhibitor Ro20-1724 on the learning and memory disorders in young rats after repeated ketamine anesthesia and its regulation to the cAMP/protein kinase A (PKA)-cAMP response element binding protein (CREB)-brain-derived neurotrophic factor (BDNF)signaling pathway. METHODS Eighty 6-week old SD rats were bought, 20 of which were randomly selected as normal control. The remaining 60 rats were randomly divided into model group and observation group (n = 30).After anesthesia with ketamine ( 50 mg·kg^-1) for 30 min, the rats of the model group were intraperitoneally injected with saline 2 mL, and the rats of the observation group were intraperitoneally injected with Ro20-1724 ( 0.5 mg·kg^-1), once a day for 7 days. The memory functions were determined by Morris water maze.Hippocampus tissues of the rats were taken. The contents of cAMP were detected by radioimmunoassay. The relative protein and mRNA expression of PKA, CREB and BDNF were detected by Western-blot and fluorescence quantitative PCR. RESULTS Compared with the normal control group, the latency period of escape from water maze and the first time of ring penetration were longer in the model group (P < 0.05), times of crossing through the platform was decreased and the content of cAMP was lower (P < 0.05). Compared with the model group, escape latency was shortened, the first time through the platform was decreased, and times of crossing were increased in the observation group (P < 0.05). The content of cAMP in the observation group was higher than that in the model group (P < 0.05), but lower than that in the normal control group (P < 0.05).The results of Western-blot and fluorescence quantitative PCR showed that the relative protein and mRNA expression levels of PKA, CREB and BDNF in the observation group were all higher than those in the model group (P < 0.05), with no significant difference from the normal control group (P > 0.05). CONCLUSION Ro20-1724 can improve the learning and memory disorders of young rats caused by repeated ketamine anesthesia by regulating the c AMP/PKA-CREB-BDNF signaling pathway.