模拟失重大鼠肺组织肺炎链球菌感染的病理改变

目的 建立模拟失重条件下大鼠细菌性肺炎的动物模型,观察模拟失重对大鼠肺组织肺炎链球菌感染的影响. 方法 36只雄性Wistar大鼠按随机数字表法分为失重感染（weightless and infection,WI）组、失重对照（weightlessness and control,WC）组和1G重力感染（1 G gravity and infection,GI）组,每组12只.实验第8天（注入细菌后的第6天）处死各组大鼠,检测血常规、C-反应蛋白（C-reactive protein,CRP）及CD4 T淋巴细胞和CD8 T淋巴细胞的比值（CD4＋/CD8＋）.观察大鼠肺组织病理变化. 结果 各组大鼠白细胞计数差异无统计学意义,中性粒细胞（neutrophils,NEU）计数及NEU比值差异有统计学意义（F=6.12、4.23,P＜0.01、＜0.05）,其中WI组最高;3组大鼠的CRP差异有统计学意义（F=19.49,P＜0.01）,其中WI组最高,WC组最低;各组大鼠外周血中CD4＋/CD8＋差异无统计学意义.WI组肺组织病理改变最严重,炎症反应较重;GI组可见部分肺组织病理改变,炎症反应程度较轻;WC组肺组织病理改变和炎症反应均最轻. 结论 模拟失重（微重力）状态下大鼠机体免疫功能降低,肺炎链球菌肺部感染的病理改变严重,炎症反应较重.

The pathological changes of weightlessness simulation on streptococcus pneumoniae infection to the lung tissue of rats

Objective To establish bacterial pneumonia model of rats in simulated weightlessness state,and to observe the effects of weightless on streptococcus pneumoniae infection to the lung tissue of rats.Methods Thirty-six male Westar rats were randomly divided into weightlessness and infection （WI） group （n=12）,weightlessness and control （WC） group （n=12）,and 1 G gravity and infection （GI） group （n=12）.On the 8th day after bacterial suspension instilled into trachea,the rats were killed.The leukocytes and neutrophils,C-reactive protein level,CD4＋/CD8＋ ratios in the peripheral blood were analyzed.The pathology of lung tissue was also observed.Results There were statistical significances of neutrophilic granulocyte count （NEU）,neutrophilic granulocyte percentage （NEU%） among three groups （F=6.12,P〈0.01 and F=4.23,P〈0.05 respectively）,and the WI group showed the highest values but no statistical difference was found in leukocytes count.The WI group had the highest level of CRP while the WC group had the lowest,and statistical significances were seen among three groups （F=19.49,P〈0.01）.But CD4＋/CD8＋ ratios in peripheral blood among three groups had no statistical differences.The changes of lung pathology in WI group were the most severe.Some of these changes were also visible in WC group and GI group,but the inflammatory response to a lesser extent,and the pathological changes were the least in WC group.Conclusions The immune function of rat would reduce in weightlessness environment.Once the lung was insulted by streptococcus pneumoniae,the pathological changes and inflammatory response become more severe.