Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA.
Crit Care Med. 2012 Aug;40(8):2407-16. doi: 10.1097/CCM.0b013e318253563c.
High doses or prolonged exposure to ketamine increase neuronal apoptosis in the developing brain, although effects on neural stem progenitor cells remain unexplored. This study investigated dose- and time-dependent responses to ketamine on cell death and neurogenesis in cultured rat fetal cortical neural stem progenitor cells.
Laboratory-based study.
University research laboratory.
Sprague-Dawley rats.
Neural stem progenitor cells were isolated from the cortex of Sprague-Dawley rat fetuses on embryonic day 17. In dose-response experiments, cultured neural stem progenitor cells were exposed to different concentrations of ketamine (0-100 µM) for 24 hrs. In time-course experiments, neural stem progenitor cells cultures were exposed to 10 µM ketamine for different durations (0-48 hrs).
Apoptosis and necrosis in neural stem progenitor cells were assessed using activated caspase-3 immunostaining and lactate dehydrogenase assays, respectively. Proliferative changes in neural stem progenitor cells were detected using bromo-deoxyuridine incorporation and Ki67 immunostaining. Neuronal differentiation was assessed using Tuj-1 immunostaining. Cultured neural stem progenitor cells were resistant to apoptosis and necrosis following all concentrations and durations of ketamine exposure tested. Ketamine inhibited proliferation with decreased numbers of bromo-deoxyuridine-positive cells following ketamine exposure to 100 µM for 24 hrs (p<.005) or 10 µM for 48 hrs (p< .01), and reduced numbers of Ki67-positive cells following exposure to ketamine concentration>10 µM for 24 hrs (p<.001) or at 10 µM for 48 hrs (p<.01). Ketamine enhanced neuronal differentiation, with all ketamine concentrations increasing Tuj-1-positive neurons (p<.001) after 24-hrs of exposure. This also occurred with all exposures to 10 µM ketamine for >8 hrs (p<.001).
Clinically relevant concentrations of ketamine do not induce cell death in neural stem progenitor cells via apoptosis or necrosis. Ketamine alters the proliferation and increases the neuronal differentiation of neural stem progenitor cells isolated from the rat neocortex. These studies imply that ketamine exposure during fetal or neonatal life may alter neurogenesis and subsequent brain development.
大剂量或长时间接触氯胺酮会增加发育中大脑中的神经元凋亡，尽管其对神经干细胞前体细胞的影响仍不清楚。本研究旨在探讨氯胺酮对培养的大鼠胎皮质神经干细胞前体细胞的细胞死亡和神经发生的剂量和时间依赖性反应。
基于实验室的研究。
大学研究实验室。
斯普拉格-道利大鼠。
从胚胎第 17 天的斯普拉格-道利大鼠胎脑中分离出神经干细胞前体细胞。在剂量反应实验中，将培养的神经干细胞前体细胞暴露于不同浓度的氯胺酮（0-100μM）24 小时。在时间过程实验中，将神经干细胞前体细胞培养物暴露于 10μM 氯胺酮不同时间（0-48 小时）。
使用激活的 caspase-3 免疫染色和乳酸脱氢酶测定分别评估神经干细胞前体细胞的凋亡和坏死。用溴脱氧尿苷掺入和 Ki67 免疫染色检测神经干细胞前体细胞的增殖变化。用 Tuj-1 免疫染色评估神经元分化。在测试的所有浓度和持续时间的氯胺酮暴露后，培养的神经干细胞前体细胞对凋亡和坏死均具有抗性。氯胺酮抑制增殖，用溴脱氧尿苷阳性细胞的数量减少，在 100μM 氯胺酮暴露 24 小时（p<0.005）或 10μM 氯胺酮暴露 48 小时（p<0.01），Ki67 阳性细胞的数量减少，在氯胺酮浓度>10μM 暴露 24 小时（p<0.001）或 10μM 暴露 48 小时（p<0.01）。氯胺酮增强神经元分化，所有氯胺酮浓度在 24 小时暴露后增加 Tuj-1 阳性神经元（p<0.001）。在所有 10μM 氯胺酮暴露>8 小时（p<0.001）也发生了这种情况。
临床相关浓度的氯胺酮不会通过凋亡或坏死诱导神经干细胞前体细胞死亡。氯胺酮改变了神经干细胞前体细胞的增殖并增加了其神经元分化。这些研究表明，在胎儿或新生儿期接触氯胺酮可能会改变神经发生和随后的大脑发育。
