J Neuroinflammation 2011 ;8 118. [IF:5.785]
Treatment with gelsolin reduces brain inflammation and apoptotic signaling in mice following thermal injury.
Zhang QH , Chen Q , Kang JR , Liu C , Dong N , Zhu XM , Sheng ZY , Yao YM .
Department of Microbiology and Immunology, Burns Institute, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing 100048, PR China.
微生物及免疫学系烧伤研究所，北京中国人民解放军总医院第一附属医院
Abstract
Burn survivors develop long-term cognitive impairment with increased inflammation and apoptosis in the brain. Gelsolin, an actin-binding protein with capping and severing activities, plays a crucial role in the septic response. We investigated if gelsolin infusion could attenuate neural damage in burned mice. Mice with 15% total body surface area burns were injected intravenously with bovine serum albumin as placebo (2 mg/kg), or with low (2 mg/kg) or high doses (20 mg/kg) of gelsolin. Samples were harvested at 8, 24, 48 and 72 hours postburn. The immune function of splenic T cells was analyzed. Cerebral pathology was examined by hematoxylin/eosin staining, while activated glial cells and infiltrating leukocytes were detected by immunohistochemistry. Cerebral cytokine mRNAs were further assessed by quantitative real-time PCR, while apoptosis was evaluated by caspase-3. Neural damage was determined using enzyme-linked immunosorbent assay of neuron-specific enolase (NSE) and soluble protein-100 (S-100). Finally, cerebral phospho-ERK expression was measured by western blot. Gelsolin significantly improved the outcomes of mice following major burns in a dose-dependent manner. The survival rate was improved by high dose gelsolin treatment compared with the placebo group (56.67% vs. 30%). Although there was no significant improvement in outcome in mice receiving low dose gelsolin (30%), survival time was prolonged against the placebo control (43.1 ± 4.5 h vs. 35.5 ± 5.0 h; P < 0.05). Burn-induced T cell suppression was greatly alleviated by high dose gelsolin treatment. Concurrently, cerebral abnormalities were greatly ameliorated as shown by reduced NSE and S-100 content of brain, decreased cytokine mRNA expressions, suppressed microglial activation, and enhanced infiltration of CD11b+ and CD45+ cells into the brain. Furthermore, the elevated caspase-3 activity seen following burn injury was remarkably reduced by high dose gelsolin treatment along with down-regulation of phospho-ERK expression. Exogenous gelsolin infusion improves survival of mice following major burn injury by partially attenuating inflammation and apoptosis in brain, and by enhancing peripheral T lymphocyte function as well. These data suggest a novel and effective strategy to combat excessive neuroinflammation and to preserve cognition in the setting of major burns.
摘要
烧伤幸存者存在着长期的认知功能障碍，并且伴随着脑细胞炎症和凋亡的发生。凝溶胶蛋白Gelsolin，是一种肌动蛋白结合蛋白，具有切断纤丝和封端的活性，在败血症发生的过程中起着重要的作用。我们通过实验研究了输注gelsolin是否可以减轻烧伤小鼠的神经损伤。体表烧伤面积15％的小鼠静脉注射牛血清白蛋白作为安慰剂组（2毫克/千克），静脉注射给予低剂量gelsolin（2毫克/千克），或高剂量的gelsolin（20毫克/千克）作为实验组。实验标本分别在烧伤后8，24，48和72小时取材。我们分析了脾T淋巴细胞的免疫功能，通过苏木素/伊红（HE）染色脑组织病理切片，采用免疫组化方法检测激活的神经胶质细胞和粒细胞浸润。脑内细胞因子的mRNA的转录情况使用实时定量PCR检测，通过检测caspase-3的活化观察了脑细胞的凋亡情况，采用酶联免疫吸附分析（ELISA）的方法测定神经元特异性烯醇化酶（NSE）和可溶性蛋白-100（S-100）来评估神经损伤的程度。此外，我们还采用免疫印迹法（western blot）检测了脑细胞磷酸化ERK的表达情况。结果显示：gelsolin呈剂量依赖性地显著提高了小鼠重度烧伤后的预后。高剂量gelsolin组生存率与安慰剂组相比得到了显著提高（56.67％与30％）。虽然低剂量gelsolin组的预后没有得到显著改变（30％），但存活时间较安慰剂组得到了延长（43.1±4.5小时与35.5±5.0小时，P <0.05）。同时高剂量的gelsolin治疗大大减轻了烧伤引起的T淋巴细胞活性的抑制。此外，脑的损伤得到了明显地改善，结果显示脑中NSE和S-100的表达下降，细胞因子mRNA的转录减少，小胶质细胞的活化得到了抑制，浸润进入大脑的CD11b +和CD45+的细胞增多。高剂量gelsolin的治疗还能够显著降低烧伤后caspase-3蛋白的激活和磷酸化ERK的表达。总而言之，外源性gelsolin的输注可以通过一定程度地减轻脑细胞的炎症和凋亡、增强T淋巴细胞的功能来提高烧伤小鼠的存活率。这些数据提供了一个新的、有效的对策来治疗大面积烧伤后严重的神经炎症并且来保护认知功能。
