Department of Neuroscience and Physiology, State University of New York - Upstate Medical University, Syracuse, NY 13210, USA.
Department of Neuroscience and Physiology, State University of New York - Upstate Medical University, Syracuse, NY 13210, USA; Department of Anatomical Sciences, Touro University, Middletown, NY 10940, USA; Developmental Exposure Alcohol Research Center, Syracuse, NY 13210, USA.
Neuroscience. 2018 Jan 15;369:278-291. doi: 10.1016/j.neuroscience.2017.11.013. Epub 2017 Nov 12.
Fetal alcohol spectrum disorder is associated with defects in neuronal generation, migration, and differentiation. The present study tested the hypothesis that ethanol exposure during the period of naturally occurring neuronal death causes a time- and Bax-dependent neuronal loss. Wild-type and Bax knockout mice were given a pair of injections (two hours apart) of ethanol (2.5 g/kg) or saline on postnatal day (P) 4, P7, P10, or P13. Mean blood ethanol concentration was 435 mg/dl one hour after the second injection. The total numbers of neurons in individual layers of somatosensory cortex were stereologically determined in 30-day-old mice and the expressions of active caspase 3 immunopositivity and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) were determined 2-36 h after the first injection. On P30, ethanol caused up to 36% neuronal loss in cortical laminae of wild-type mice. In contrast, no ethanol-induced loss was detected in Bax knockout mice. Ethanol also caused an acute bilaminar (layers II/III and V) increase in caspase 3 immunoexpression and TUNEL in wild-type mice. The changes in the expression of these markers were age- and lamina-dependent. No ethanol-induced expression of caspase 3 or TUNEL was detected in Bax knockout animals. Thus, ethanol-induced death of cortical neurons is Bax-dependent, occurs concurrently in all layers, but does not correspond to lamina- and age-dependent expression of DNA fragmentation. Both ethanol-induced and naturally occurring death of cortical neurons rely on caspase 3-dependent and independent mechanisms.
胎儿酒精谱系障碍与神经元发生、迁移和分化缺陷有关。本研究检验了这样一个假设，即在自然发生的神经元死亡期间暴露于乙醇会导致时间和 Bax 依赖性神经元丢失。在出生后第 4、7、10 或 13 天，野生型和 Bax 敲除小鼠接受了一对（相隔两小时）乙醇（2.5g/kg）或盐水注射。第二次注射后一小时，平均血液乙醇浓度为 435mg/dl。在 30 日龄的小鼠中通过立体学确定了感觉皮层各层的神经元总数，并在第一次注射后 2-36 小时确定了活性 caspase 3 免疫阳性和末端脱氧核苷酸转移酶 dUTP 缺口末端标记 (TUNEL) 的表达。在 P30，乙醇导致野生型小鼠皮质层多达 36%的神经元丢失。相比之下，在 Bax 敲除小鼠中未检测到乙醇诱导的丢失。乙醇还导致野生型小鼠中 caspase 3 免疫表达和 TUNEL 的急性双皮层（层 II/III 和 V）增加。这些标志物表达的变化与年龄和层有关。在 Bax 敲除动物中未检测到乙醇诱导的 caspase 3 或 TUNEL 表达。因此，皮质神经元的乙醇诱导死亡依赖于 Bax，同时发生在所有层中，但与 DNA 片段化的层和年龄依赖性表达不对应。乙醇诱导和自然发生的皮质神经元死亡都依赖于 caspase 3 依赖性和非依赖性机制。
