CD44在大鼠急性颈脊髓损伤后肺水肿中的作用

Role of CD44 in pulmonary edema in spinal cord injured rats

[目的]探讨大鼠急性颈脊髓损伤后不同时间节点血清及肺泡灌洗液中CD44含量的变化与肺水肿的关系。[方法]成年Wistar大鼠40只,体重240～250 g,雌雄不限。大鼠随机分为实验组和对照组,每组20只,每组又分为造模后24 h、3 d、1、2周共4个时间点,每个时间点5只大鼠。实验组采用C7段脊髓改良Allen's打击法制作大鼠脊髓损伤模型,打击力度为10×2.5 g.cm;对照组只暴露C7脊髓。在不同时间点处死大鼠,检测各时间点两组大鼠血清和肺泡灌洗液中CD44含量和蛋白浓度,计算肺通透指数。[结果]急性脊髓损伤大鼠伤后肺泡灌洗液的CD44无明显变化,血清CD44含量于伤后24 h开始下降,伤后3 d达最低值,伤后1周含量开始回升,伤后24 h和3 d实验组大鼠血清CD44含量与假手术组有显著差异性。CD44含量变化周期与SCI后肺水肿及肺病理变化周期呈负相关。[结论]血清CD44含量变化周期与SCI后肺水肿及肺病理变化周期呈负相关,急性脊髓损伤后肺水肿的形成过程可能与SCI后血清CD44含量下降有关。

[Objective]To investigate the relationship between pulmonary edema and the change of CD44 in serum and bronchoalveolar lavage fluid at different time points in acute spinal cord injured rats.[Method] Forty Wistar rats with 240 g to 250 g in weight were divided into two groups：control group（n=20） and injury group（n=20）.The two groups were respectively subdivided into groups of 24 hours,3 days,1 week,and 2 weeks after the models had been created.The spinal cord injury（SCI） models were induced at the C7 level by dropping a weight of 10 g from the height of 25 mm（Allen＇s model）.In the control group,laminas were removed only,leaving spinal cord at the C7 lerel intact.All the animals were sacrificed at the 4 time points.The content of CD44 and protein concentration in serum and BALF were measured.Then the lung permeability index（LPI） was calculated. [Result]In the injury group the content of CD44 in bronchoalveolar lavage fluid had no obvious difference.But in serum the content of CD44 began decreasing at 24 hours,and reached trough at 3 days.The deviation of CD44 in injury group at 24 hours,and 3 days after the models had been created was significant compared with that in control group（P0.05）.The change of LPI showed negative correlation with that of CD44.[Conclusion]The change of CD44 in serum has negative correlation with the degree of pulmonary edema in acute spinal cord injured rats.The development of pulmonary edema in SCI rats has relationship with the content of CD44 in serum.