Jiao Zhuo-Min, Fu Yu-Hong, Fu Jin, Zhang Feng, Wang Wei-Zhi
Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China.
Zhonghua Yi Xue Za Zhi. 2008 Aug 26;88(33):2350-4.
To investigate the mechanism of rapid amelioration of the pathological changes in experimental allergic encephalomyelitis (EAE) by 1, 25-dihydroxyvitamin D(3) [1, 25-(OH)(2)D(3)].
Forty Lewis rats were immunized with myelin basic protein in complete Freud's adjuvant so as to establish ESE animal models and then randomly divided into 4 equal groups: prevention group, fed with 1, 25-(OH)(2)D(3) since day 0 for 10 days, prevention-control group fed with peanut oil for 10 days, treatment group fed with 1, 25-(OH)(2)D(3) since the appearance of EAE symptoms (generally since day 10 or 11), and treatment-control group fed with peanut oil since the appearance of EAE symptoms. The clinical symptoms were scored since immunization till day 12 when the clinical symptoms reached the maximum level. The rats were sacrificed 13 days after sensitization with their brains and spinal cords taken out to undergo pathological examination, in situ TUNEL staining for detecting apoptotic cells, and semiquantitative immunohistochemical analysis to detect the inducible NO synthase (iNOS), FasL, and tumor growth factor (TGF)-beta 1, that might involve in the signal pathway of apoptosis. Peripheral blood samples were collected to isolate mononuclear cells (MNCs). The content of nitrite in the supernatant of MNC culture was evaluated.
The scores of clinical symptoms and the pathological changes of both the prevention and treatment groups decreased conspicuously and were significantly lower than their respective control groups (both P < 0.01). In contrast, the apoptosis indexes of the 2 1, 25-(OH)(2)D(3) administration groups were significantly higher than those of the control groups (all P < 0.01). The TUNEL positive cell rates in the brain and spinal cord of the treatment and prevention groups were all significantly higher than those of their corresponding control groups (P < 0.05, P < 0.01). The numbers of iNOS positive cells in the treatment and prevention groups were both lower than those of their corresponding control groups, which was in accord with the improvement of clinical signs and tissue lesions. The levels of nitrite in the supernatant of MNC culture of the treatment and prevention groups were higher than those of their corresponding control groups, but not significantly.
Administration of 1, 25-(OH)(2)D(3) rapidly ameliorates EAE symptoms by promoting the apoptosis of inflammatory cells. The elimination of infiltrating immune cells which reverses the pathological changes in central nervous system is associated with a favorable microenvironment provided by 1, 25-(OH)(2)D(3), such as decreasing of iNOS.
探讨1,25 - 二羟基维生素D₃[1,25-(OH)₂D₃]快速改善实验性变态反应性脑脊髓炎（EAE）病理变化的机制。
40只Lewis大鼠用髓鞘碱性蛋白与完全弗氏佐剂免疫以建立EAE动物模型，然后随机分为4组，每组10只：预防组自第0天起给予1,25-(OH)₂D₃，连续10天；预防对照组给予花生油，连续10天；治疗组自出现EAE症状（一般自第10或11天起）给予1,25-(OH)₂D₃；治疗对照组自出现EAE症状起给予花生油。自免疫至第12天临床症状达最高水平时对临床症状进行评分。致敏13天后处死大鼠，取出脑和脊髓进行病理检查、原位TUNEL染色检测凋亡细胞，以及半定量免疫组化分析检测可能参与凋亡信号通路的诱导型一氧化氮合酶（iNOS）、FasL和肿瘤生长因子（TGF）-β1。采集外周血样本分离单个核细胞（MNCs）。评估MNC培养上清中亚硝酸盐含量。
预防组和治疗组的临床症状评分及病理变化均显著降低，且明显低于各自的对照组（均P < 0.01）。相比之下，两个1,25-(OH)₂D₃给药组的凋亡指数均显著高于对照组（均P < 0.01）。治疗组和预防组脑和脊髓中的TUNEL阳性细胞率均显著高于相应对照组（P < 0.05，P < 0.01）。治疗组和预防组中iNOS阳性细胞数均低于相应对照组，这与临床症状和组织损伤的改善情况相符。治疗组和预防组MNC培养上清中亚硝酸盐水平高于相应对照组，但差异无统计学意义。
给予1,25-(OH)₂D₃可通过促进炎性细胞凋亡快速改善EAE症状。炎性浸润免疫细胞的清除逆转了中枢神经系统的病理变化，这与1,25-(OH)₂D₃提供的良好微环境有关，如iNOS减少。
