Haddadi Gholam Hassan, Fardid Reza
Department of Medical Physics, Fasa University of Medical Sciences, Fasa, Iran ; Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
Rep Pract Oncol Radiother. 2015 Feb 21;20(2):123-7. doi: 10.1016/j.rpor.2014.11.003. eCollection 2015 Mar-Apr.
We aimed to determine the changes in TNF-α expression and Malondialdehyde (MDA) level in a short time after irradiation. Furthermore, we evaluated the effect of melatonin on the modulation of TNF-α gene expression.
The radio-sensitivity of the cervical spinal cord limits the dose of radiation which can be delivered to tumors in the neck region. There is increasing evidence that TNF-α has a role in the development of the acute phase of spinal cord injury.
MATERIALS/METHODS: Four groups of rats were investigated. Group 1 (vehicle treatment) served as the control. Group 2 (radiation) was treated with the vehicle, and 30 min later, the rats were exposed to radiation. Group 3 (radiation + melatonin) was given an oral administration of melatonin (100 mg/kg body weight) and 30 min later exposed to radiation in the same manner as in group 2. Group 4 (melatonin-only) was also given an oral administration of melatonin (100 mg/kg body weight). 5 mg/kg of melatonin was administered daily to rats in groups 3 and 4, and the vehicle was administered daily to rats in groups 1 and 2.
Three weeks after irradiation, TNF-α gene up-regulated almost 5 fold in the irradiated group compared to the normal group. TNF-α gene expression in the melatonin pretreatment group, compared to the radiation group, was significantly down-regulated 3 weeks after irradiation (p < 0.05). MDA levels increased after irradiation and then significantly decreased under melatonin treatment.
We suggest that inhibition of TNF-α expression by oral administration of melatonin may be a therapeutic option for preventing radiation-induced spinal cord injury.
我们旨在确定照射后短时间内肿瘤坏死因子-α（TNF-α）表达及丙二醛（MDA）水平的变化。此外，我们评估了褪黑素对TNF-α基因表达调节的影响。
颈段脊髓的放射敏感性限制了可用于颈部肿瘤的放射剂量。越来越多的证据表明，TNF-α在脊髓损伤急性期的发展中起作用。
材料/方法：对四组大鼠进行研究。第1组（载体处理）作为对照。第2组（辐射组）用载体处理，30分钟后，大鼠接受辐射。第3组（辐射 + 褪黑素组）口服褪黑素（100毫克/千克体重），30分钟后以与第2组相同的方式接受辐射。第4组（仅褪黑素组）也口服褪黑素（100毫克/千克体重）。第3组和第4组的大鼠每天给予5毫克/千克的褪黑素，第1组和第2组的大鼠每天给予载体。
照射后三周，与正常组相比，照射组的TNF-α基因上调了近5倍。与辐射组相比，褪黑素预处理组在照射后三周的TNF-α基因表达显著下调（p < 0.05）。照射后MDA水平升高，然后在褪黑素治疗下显著降低。
我们认为口服褪黑素抑制TNF-α表达可能是预防辐射诱导的脊髓损伤的一种治疗选择。
