TNF-α对小鼠肺泡巨噬细胞CD14和清道夫受体表达的影响

Effects of TNF-α on expression of CD14 and scavenger receptorof mouse alveolar macrophages

本研究旨在通过观察TNF α对肺泡巨噬细胞 (AM)清道夫受体 (SR)、CD14表达的影响 ,探讨TNF α在内毒素血症时AM由早期防御性 (清除、灭活内毒素 )向后期效应性 (释放大量的致炎与抗炎因子 )转变中的作用。分离培养小鼠AM ,以不同剂量TNF α(0 ,0 0 0 1,0 0 1,0 1,1,10 ,10 0 μg L)刺激细胞 16h或以 10 0 μg LTNF α刺激细胞不同时间 (0 ,2 ,4 ,6 ,8,12 ,16 ,2 4h) ,采用免疫细胞化学及RT PCR方法观察SR、CD14表达变化。结果显示 ,以低至 0 1μg LTNF α刺激16h或 10 0 μg LTNF α刺激 6h以上就能显著增强CD14并抑制SR蛋白的表达 ,实验同时显示 ,CD14mRNA、SRmRNA表达也显著增强 ,SRmRNA表达变化与SR蛋白表达趋势不一致。研究结果提示 ,TNF α能通过增强CD14蛋白表达并抑制SR蛋白表达而在内毒素血症时小鼠AM由免疫防御型向炎症效应型转变中发挥重要作用。

To demonstrate the role of TNF-α in AM transformation from defence stage (clearance and inactivation of lipopolysaccharides) to effective stage (release of a mount of pro-inflammation and anti-inflammation factors) during endotoximia by studying the effects of TNF-α on expression of CD14 and scavenger receptor (SR) on murine alveolar macrophages (AM). After been separated and cultured for addition 24 hours, mice AM were incubated with different dose (0,0.001,0.01,0.1,1,10,100μg/L) of TNF-α for 16 hours(h) or with 100μg/L TNF-α for different time (0,2,4,6,8,12,16,24h). Immunocytochemistry and RT-PCR were used to detect the expression of CD14 and SR on protein and mRNA levels. CD14 protein expression was up-regulated and SR protein expression was significantly reduced when AM were stimulated by TNF-α with 0.1μg/L or above concentrations for 16h or with 100μg/L TNF-α for 6h or above, the CD14mRNA and SRmRNA expression were also enhanced at the same time, the SRmRNA expression was not positively related to its protein alteration. The data suggests that TNF-α may have a critical role in prompting the AM transformation from defence stage to effective stage during mouse endotoximia by altering the expression of CD14 and SR protein.