Ucar T, Ozkaya G, Demir N, Gurer I, Akyuz M, Onal M Z
Department of Neurosurgery, School of Medicine, University of Akdeniz, Antalya, Turkey.
Acta Neurol Scand. 2005 Sep;112(3):163-72. doi: 10.1111/j.1600-0404.2005.00463.x.
The aim of this study was to investigate the effects of environmental light-dark changes on the outcome of mild traumatic brain injury (MTBI) using an experimental rodent model. The functions of endogenous and exogenous melatonin on the outcome of injury were also investigated
Mild traumatic brain injury was experimentally induced in 56 male Sprague-Dawley rats using a weight-drop device. Animals were divided into four groups of 14 each as follows: (i) sham-operated (trauma only, normal day-night cycle), (ii) treated with melatonin (trauma+melatonin, normal day-night cycle), (iii) darkness-induced (trauma+48 h constant dark), and (iv) treated with melatonin and darkness-induced (trauma+48 h constant dark+melatonin). Melatonin (50 mg/kg) was administered, intraperitoneally, immediately after trauma. EEG recordings were taken at three time periods (pretrauma, immediately after trauma, and 48 h after trauma). Motor functions were tested pretrauma, 24 and 48 h post-trauma. Serum melatonin levels were determined pretrauma and 48 h post-trauma. Tissue samples from right frontal area were taken 48 h after trauma for light and electron microscopic examinations.
Following MTBI light deprivation alone and light deprivation in combination with exogenously administered melatonin indicated significant neuroprotective effects. Although there may be other important pathways, darkness-induced elevation in endogenous melatonin secretion appears to play an important role in this neuroprotective outcome.
本研究旨在使用实验性啮齿动物模型，研究环境明暗变化对轻度创伤性脑损伤（MTBI）结果的影响。同时还研究了内源性和外源性褪黑素对损伤结果的作用。
使用重物下落装置对56只雄性Sprague-Dawley大鼠进行实验性轻度创伤性脑损伤。动物被分为四组，每组14只，如下：（i）假手术组（仅创伤，正常昼夜循环），（ii）褪黑素治疗组（创伤+褪黑素，正常昼夜循环），（iii）黑暗诱导组（创伤+48小时持续黑暗），以及（iv）褪黑素治疗且黑暗诱导组（创伤+48小时持续黑暗+褪黑素）。创伤后立即腹腔注射褪黑素（50mg/kg）。在三个时间段（创伤前、创伤后立即、创伤后48小时）进行脑电图记录。在创伤前、创伤后24小时和48小时测试运动功能。在创伤前和创伤后48小时测定血清褪黑素水平。创伤后48小时从右额叶区域采集组织样本进行光镜和电镜检查。
MTBI后单独的光照剥夺以及光照剥夺与外源性褪黑素联合使用均显示出显著的神经保护作用。尽管可能存在其他重要途径，但黑暗诱导的内源性褪黑素分泌升高似乎在这种神经保护结果中起重要作用。
