Tang Zhan-Hong, Pan Xuan, Hu Jun-Tao, Ji Xiao-Fang
Department of Intensive Care Unit , the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi, China.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2011 Apr;23(4):236-8.
To investigate the effect of hypothermia (HT) on the concentration of surfactant protein A (SP-A) during lipopolysaccharide (LPS) induced acute lung injury (ALI) in rats.
Forty male Wistar rats were randomly divided into three groups. The ALI model was reproduced by LPS intratracheal instillation; only saline was instilled intratracheally for control group. Rats in both model group and control group were sacrificed respectively at 1 hour and 8 hours (each n=8). In HT group the body temperature was lowered to 32.5-33.0 centigrade 1 hour after LPS instillation, and 8 rats were sacrificed at 8 hours. The arterial blood gas was determined in all the groups before and 1 hour and 8 hours after instillation of saline or LPS, and the oxygenation index (PaO(2)/FiO(2)) was calculated. The concentration of SP-A in bronchoalveolar lavage fluid (BALF) was determined by enzyme linked immunosorbent assay. The morphological changes in lung tissue of rats were observed under light microscope.
At 1 hour after intratracheal instillation of LPS, the PaO(2)/FiO(2) of each group reached the diagnostic criterion of ALI. Compared with control 1 hour group, the SP-A (μg/L) in BALF of model 1 hour group was decreased (53.27±1.95 vs. 74.81±6.55, P<0.01); the SP-A in model 8 hour group and HT 8 hour group (4.35±2.76 and 51.36±2.33) was both obviously decreased compared with control 8 hour group (70.81±5.01, both P<0.01). Compared with model 8 hour group, the SP-A of HT 8 hour group was obviously increased (P<0.01). Results of light microscopic examination, it was revealed that the alveolar structure of control 1 hour group and control 8 hour group was almost normal. Inflammatory response in lung tissues in model 8 hour group was found to be most serious; compared with model 8 hour group, inflammatory response in lung tissues in model 1 hour group and HT 8 hour group was reduced in certain degree.
A certain extent of HT may reduce lung injury of early endotoxin induced ALI rats by delaying lowering of alveolar SP-A levels.
探讨低温（HT）对脂多糖（LPS）诱导的大鼠急性肺损伤（ALI）过程中表面活性蛋白A（SP-A）浓度的影响。
40只雄性Wistar大鼠随机分为三组。通过气管内滴注LPS建立ALI模型；对照组仅气管内滴注生理盐水。模型组和对照组大鼠分别在1小时和8小时处死（每组n = 8）。HT组在LPS滴注后1小时将体温降至32.5 - 33.0摄氏度，8小时后处死8只大鼠。在所有组中，于滴注生理盐水或LPS前、滴注后1小时和8小时测定动脉血气，并计算氧合指数（PaO₂/FiO₂）。采用酶联免疫吸附测定法测定支气管肺泡灌洗液（BALF）中SP-A的浓度。在光学显微镜下观察大鼠肺组织的形态学变化。
气管内滴注LPS后1小时，各组的PaO₂/FiO₂均达到ALI的诊断标准。与对照组1小时组相比，模型组1小时组BALF中SP-A（μg/L）降低（53.27±1.95 vs. 74.81±6.55，P<0.01）；与对照组8小时组相比，模型组8小时组和HT组8小时组的SP-A（4.35±2.76和51.36±2.33）均明显降低（均P<0.01）。与模型组8小时组相比，HT组8小时组的SP-A明显升高（P<0.01）。光学显微镜检查结果显示，对照组1小时组和对照组8小时组的肺泡结构基本正常。模型组8小时组肺组织的炎症反应最为严重；与模型组8小时组相比，模型组1小时组和HT组8小时组肺组织的炎症反应有一定程度减轻。
一定程度的低温可能通过延缓肺泡SP-A水平降低减轻早期内毒素诱导的ALI大鼠的肺损伤。
