Developmental neurotoxicity of ketamine: Morphometric confirmation, exposure parameters, and multiple fluorescent labeling of apoptotic neurons
Developmental neurotoxicity of ketamine: Morphometric confirmation, exposure parameters, and multiple fluorescent labeling of apoptotic neurons
复制标题
DOI：
10.1093/toxsci/kfh224
复制
发表时间：
2004-10-01
影响因子：
3.8
通讯作者：
Hanig, JP
中科院分区：
文献类型：
--
作者：
Scallet, AC;Schmued, LC;Hanig, JP
氯胺酮是最近报道的一种广泛使用的儿科麻醉剂（C. Ikonomidou et al., 1999, Science 283, 70-74），可增加新生大鼠的神经元死亡。为了证实和扩展这些结果，我们给四组PND 7大鼠注射了7次剂量，每90分钟一次，分别是生理盐水、10 mg/kg氯胺酮、20 mg/kg氯胺酮或单剂量20 mg/kg氯胺酮。20 mg/kg氯胺酮的重复剂量增加了丘脑背外侧银阳性（退化）神经元的数量，其程度与先前的结果相当（Ikonomidou等人，1999,Science 283, 70-74），即分别是28倍和31倍。然而，在重复20毫克/公斤剂量后，氯胺酮的血液浓度立即达到14马克/毫升，大约是麻醉后人体血液浓度的7倍(J. M. Malinovsky et al., 1996, Br。[j] .农业科学学报，2007 (3):391 - 391；R. A. Mueller和R. Hunt, 1998, Pharmacol。物化学。行为，60,15-22)。暴露于多次10mg /kg剂量氯胺酮或单次20mg /kg剂量氯胺酮后，血液中的氯胺酮水平约为2-5马克杯/毫升；虽然这些血液浓度接近人类的麻醉水平，但它们没有产生神经变性。为了研究氯胺酮诱导的神经元死亡模式，冠状切片用Fluoro-Jade B（一种对神经变性有选择性的绿色荧光染色剂）和DAPI（一种蓝色DNA染色剂）以及caspase-3（使用罗丹明标记为红色的抗血清）进行染色。这些组织化学结果证实了氯胺酮的发育神经毒性，表明氟玉B （FJ-B）与银法一样成功染色新生大鼠变性神经元，表明氯胺酮通过增加神经元凋亡率起作用。
Ketamine is a widely used pediatric anesthetic recently reported (C. Ikonomidou et al., 1999, Science 283, 70-74) to enhance neuronal death in neonatal rats. To confirm and extend these results, we treated four groups of PND 7 rats with seven sc doses, one every 90 min, of either saline, 10 mg/kg ketamine, 20 mg/kg ketamine, or a single dose of 20 mg/kg ketamine. The repeated doses of 20 mg/kg ketamine increased the number of silver-positive (degenerating) neurons in the dorsolateral thalamus to a degree comparable to previous results (Ikonomidou et al., 1999, Science 283, 70-74), i.e., 28-fold vs. 31-fold respectively. However, blood levels of ketamine immediately after the repeated 20 mg/kg doses were about 14 mug/ml, about seven-fold greater than anesthetic blood levels in humans (J. M. Malinovsky et al., 1996, Br. J. Anaesth. 77, 203-207; R. A. Mueller and R. Hunt, 1998, Pharmacol. Biochem. Behav. 60, 15-22). Levels of ketamine in blood following exposure to the multiple 10 mg/kg doses of ketamine or to a single 20 mg/kg dose ranged around 2-5 mug/ml; although these blood levels are close to an anesthetic level in humans, they failed to produce neurodegeneration. To investigate the mode of ketamine-induced neuronal death, coronal sections were stained with both Fluoro-Jade B (a green fluorescent stain selective for neurodegeneration) and DAPI (a blue DNA stain), as well as for caspase-3 (using an antisera labeled red with rhodamine). These histochemical results confirmed the developmental neurotoxicity of ketamine, demonstrated that Fluoro-Jade B (FJ-B), like silver methods, successfully stained degenerating neurons in neonatal rats, and indicated that ketamine acts by increasing the rate of neuronal apoptosis.