哮喘大鼠大脑和肺组织c-fos蛋白表达与神经免疫调节

背景越来越多的研究事实表明免疫系统不是一个仅有自主调节的孤立系统,而是与中枢神经系统之间存在双向联系.目的探讨哮喘大鼠肺脏和大脑中c-fos表达的分布及其意义.设计随机对照实验.单位南方医科大学南方医院肿瘤科和珠江医院神经外科.材料实验在2004-01/08在南方医科大学南方医院肿瘤科实验室和珠江医院神经外科完成.选择成年健康雄性大鼠14只.随机分为实验组10只和对照组4只.方法实验组第1天用卵蛋白10mg加氢氧化铝干粉200 mg与灭活百日咳菌苗5×109个配成2 mL混悬液腹腔注射,于第15天开始用10 g/L卵蛋白超声雾化吸入,2次/h,共3 d,制作卵蛋白致敏大鼠哮喘模型,对照组第1天用生理盐水2 mL腹腔注射,于第15天用生理盐水雾化吸入,30 mL/d,共3 d.所有大鼠在麻醉状态下灌流固定取肺和脑组织,采用免疫组织化学卵白素-生物素-过氧化物复合物法和图像分析等技术观察Fos蛋白在肺脏和大脑内的分布情况.主要观察指标Fos蛋白在脑内不同区域和肺脏中的分布.结果14只大鼠均进入结果分析.①哮喘组大鼠肺脏和大脑中c-fos表达明显高于对照组(P＜0.05); Fos阳性产物在脑内主要集中分布在额顶皮质、边缘前脑(扣带皮质、梨状皮质和中央杏仁核等)、丘脑室旁核、下丘脑室旁核、视上核、下丘脑外侧区、下丘脑室周核、孤束核、最后区和延髓腹外侧区内;小脑内无明显Fos分布密集区.②哮喘组气道壁及肺组织中可见大量的c-fos阳性细胞,阳性炎症细胞主要分布于黏膜层、黏膜下层及平滑肌周围;而对照组动物气道及肺组织中无或偶见免疫反应极弱的c-fos阳性细胞.结论哮喘大鼠不仅肺脏中c-fos表达明显增加,而且在延髓内脏带及其上行投射神经核团(下丘脑、杏仁核等)表达也较多,说明原癌基因c-fos表达可能与哮喘神经免疫调节密切相关.

Cerebral and lung c-fos protein expression and neuroimmunomodulation in asthmatic rats

BACKGROUND: Increasing evidence identifies the immune system not as an isolated system with automodulations, but one that interacts with the central nervous system.OBJECTIVE: To investigate the distribution of c-fos expression in the lung and brain tissues of asthmatic rats and explore is significance.DESIGN: Randomized controlled study.SETTING: Department of Oncology, Southern Hospital, and Department of Neurosurgery, Zhujiang Hospital, Southern Medical University.MATERIALS: The experiment was conducted Department of Oncology,Southern Hospital, and Department of Neurosurgery, Zhujiang Hospital,Southern Medical University, between January and August 2004. Fourteen healthy male rats were randomized into experimental group (n=10) and control group (n=4).METHODS: On the first day of experiment, the rats in experimental group received intraperitoneal injection of 2 mL of the suspension containing 10 mg albumen, 200 mg aluminum hydroxide powder and inactivated pertussis vaccine (5×109), and subjected to inhalation of ultrasonically atomized 10 g/L albumen from on the 15th day, 2 times per hour for totally 3 days, to induce asthma in the rats. The rats in the control group received intraperitoneal injection of 2 mL normal saline on the 1st day and inhalation of ultrasonically normal saline on the 15th day, 30 mL a day for totally 3 days. The lung and brain tissues of all the anesthetized rats were fixed by perfusion, and immunohistochemical method with ovin-biotin-peroxidase complex and imaging analysis system were used to observe the distribution of Fos protein in the lung and brain.MAIN OUTCOME MEASURES: Distribution of c-Fos protein in lung and cerebrum.c-Fos in the lung and brain tissues was obviously higher in asthmatic group than in the control group (P ＜ 0.05), located mainly in the parietal-fontal cortex, limbic forebrain (cingulum cortex, pyriform cortex and central amygdaloid nucleus and so on), thalamus paraventricular nucleus, hypothalamus paraventricular nucleus, supraoptic nucleus, lateral region of the hypothalamus, hypothalamus periventricular nucleus, nucleus of solitary tract,area postrema and ventrolateral medulla. No obvious Fos expression was observed in the cerebellum. A large number of c-Fos-positive cells were observed in the wall of the airway and lungs in asthmatic rats, mainly distributing in the mucous membrane and submucous layer and around the smooth muscles; in the control rats, no positive cells or only occasional cells with weak c-Fos positivity were found in the wall of the airway and lungs.CONCLUSION: c-Fos expression increases obviously not only in the lungs of asthmatic rats, but also in medullar and its ascending projecting nuclei (hypothalamus, amygdala and so on), suggesting that the expression of protooncogene c-fos might be closely related with neuroimmunomodulation in asthma.