Exogenous GM1 Ganglioside Attenuates Ketamine-Induced Neurocognitive Impairment in the Developing Rat Brain
Exogenous GM1 Ganglioside Attenuates Ketamine-Induced Neurocognitive Impairment in the Developing Rat Brain
复制标题
外源性 GM1 神经节苷脂可减轻氯胺酮诱导的大鼠大脑发育中的神经认知损伤
DOI：
10.1213/ane.0000000000004570
复制
发表时间：
2020-02-01
影响因子：
5.7
通讯作者：
Wang, Xian-yu
中科院分区：
文献类型：
--
作者：
Meng, Chen;Yao, Xue-qin;Wang, Xian-yu
背景：长期暴露于氯胺酮会引发发育中大脑的显著神经变性和长期神经认知缺陷。单唾液酸四己糖神经节苷脂（GM 1）可以限制神经退行性疾病中由坏死和凋亡引起的神经元损伤。我们的目的是评估GM 1是否可以预防氯胺酮诱导的发育神经毒性。方法：出生后第7天（P7）大鼠幼崽接受5次腹腔注射氯胺酮（每次20 mg/kg），间隔90 min，持续6 h。通过使用Morris水迷宫（MWM）确定的认知功能，包括逃避潜伏期（P32-36）和平台穿越（P37），在氯胺酮暴露的幼鼠之间进行了比较，有或没有外源性GM 1（30 mg/kg; n = 12/组）。采用末端脱氧核苷酸转移酶介导的2 '-脱氧尿苷5 '-三磷酸缺口末端标记法（TUNEL）和半胱氨酸天冬氨酸蛋白酶3（caspase 3）活性测定，观察GM 1对海马细胞凋亡的影响。Western blotting检测海马脑源性神经营养因子（BDNF）的表达，沿着蛋白激酶B（AKT）和细胞外信号相关激酶1和2（ERK 1/2）的磷酸化。在GM 1处理之前施用抗BDNF抗体（每只大鼠2 μ g）以确定GM 1的神经保护机制。研究结果：与对照组大鼠相比，接受氯胺酮暴露的大鼠在MWM测试中出现认知障碍，表现为P34（P = .006）、P35（P = .002）和P36（P = .005）的逃避潜伏期延长。然而，在GM 1预处理的大鼠，氯胺酮暴露并没有诱导延长逃避潜伏期。外源性GM 1增加了P37时的平台穿越时间（3.00 +/- 2.22倍vs 5.40 +/- 1.53倍，平均值+/-标准差; P = 0.041），并减少了氯胺酮暴露的年轻大鼠海马TUNEL阳性细胞和裂解型半胱天冬酶3的表达。氯胺酮降低了海马中BDNF的表达和AKT和ERK的磷酸化，而外源性GM 1阻断了氯胺酮引起的这些作用。然而，与免疫球蛋白Y（IgY）同种型对照相比，对于接受外源性GM 1的氯胺酮暴露大鼠幼崽，BDNF中和抗体治疗抵消了外源性GM 1诱导的P36逃避潜伏期的改善（41.32 ± 12.37秒vs 25.14 ± 8.97秒，平均值±标准差; P = 0.036）、P37时的平台穿越时间（2.16 +/- 1.12次vs 3.92 +/- 1.97次，平均值+/-标准差; P <0.036）、细胞凋亡活性以及氯胺酮激发的年轻大鼠海马中的AKT和ERK 1/2磷酸化。结论：提示外源性GM 1通过作用于BDNF信号通路，改善氯胺酮所致的幼年大鼠认知功能障碍和海马细胞凋亡。我们的研究可能表明GM 1在预防氯胺酮诱导的年轻人认知缺陷方面的潜在用途。
BACKGROUND: A prolonged exposure to ketamine triggers significant neurodegeneration and long-term neurocognitive deficits in the developing brain. Monosialotetrahexosylganglioside (GM1) can limit the neuronal damage from necrosis and apoptosis in neurodegenerative conditions. We aimed to assess whether GM1 can prevent ketamine-induced developmental neurotoxicity. METHODS: Postnatal day 7 (P7) rat pups received 5 doses of intraperitoneal ketamine (20 mg/kg per dose) at 90-minute intervals for 6 hours. Cognitive functions, determined by using Morris water maze (MWM) including escape latency (at P32-36) and platform crossing (at P37), were compared among the ketamine-exposed pups treated with or without exogenous GM1 (30 mg/kg; n = 12/group). The effect of GM1 on apoptosis in hippocampus was determined by terminal deoxynucleotidyl transferase-mediated 2 '-deoxyuridine 5 '-triphosphate nick end labeling (TUNEL) staining and activated caspase 3 measurement. The hippocampal expression of brain-derived neurotrophic factor (BDNF), along with the phosphorylation of protein kinase B (AKT) and extracellular signal-related kinases 1 and 2 (ERK1/2), was detected by western blotting (n = 6/group). Anti-BDNF antibody (2 mu g per rat) administered before GM1 treatment was applied to determine the neuroprotective mechanisms of GM1. RESULTS: The rats receiving ketamine exposure experinced cognitive impairment in MWM test compared to the control rats, indicated by prolonged escape latency at P34 (P = .006), P35 (P = .002), and P36 (P = .005). However, in GM1-pretreated rats, ketamine exposure did not induce prolonged escape latency. The exogenous GM1 increased the platform-crossing times at P37 (3.00 +/- 2.22 times vs 5.40 +/- 1.53 times, mean +/- standard deviation; P = .041) and reduced the hippocampal TUNEL-positive cells and cleaved-caspase 3 expression in ketamine-exposed young rats. Ketamine decreased BDNF expression and phosphorylation of AKT and ERK in the hippocampus, whereas exogenous GM1 blocked these ketamine-caused effects. However, for the ketamine-exposed rat pups receiving exogenous GM1, compared to immunoglobulin Y (IgY) isotype control, the BDNF-neutralizing antibody treatment counteracted the exogenous GM1-induced improvement of the escape latency at P36 (41.32 +/- 12.37 seconds vs 25.14 +/- 8.97 seconds, mean +/- standard deviation; P = .036), platform-crossing times at P37 (2.16 +/- 1.12 times vs 3.92 +/- 1.97 times, mean +/- standard deviation; P < .036), apoptotic activity, as well as AKT and ERK1/2 phosphorylation in the hippocampus of ketamine-challenged young rats. CONCLUSIONS: Our data suggest that the exogenous GM1 acts on BDNF signaling pathway to ameliorate the cognitive impairment and hippocampal apoptosis induced by ketamine in young rats. Our study may indicate a potential use of GM1 in preventing the cognitive deficits induced by ketamine in the young per se.