多壁碳纳米管抑制RAW264.7巨噬细胞的吞噬功能

目的 观察多壁碳纳米管（MWCNT）对巨噬细胞吞噬功能的影响.方法 采用常规细胞培养技术培养RAW264.7巨噬细胞;用流式细胞术定量检测RAW264.7巨噬细胞吞噬异硫氰酸荧光素标记的大肠杆菌（FITC-tagged E.coli k-12）的情况.结果 MWCNT剂量依赖性地抑制RAW264.7细胞吞噬大肠杆菌,随着MWCNT浓度的增加,RAW264.7细胞吞噬大肠杆菌的量（用平均荧光强度表示）降低.此外,MWCNT抑制RAW264.7细胞吞噬大肠杆菌亦呈时间依赖性：用MWCNT（75 μg/ml）孵育RAW264.7细胞12h后,RAW264.7细胞吞噬大肠杆菌的量与对照组相比降低了约70.4％ （P ＜0.01）,同时参与吞噬活动的RAW264.7细胞的百分比也从对照组的98.6％降低到了92.4％ （P＜0.05）.即使用低剂量的MWCNT（25 μg/ml）孵育RAW264.7细胞较长时间（24h）后,RAW264.7细胞吞噬大肠杆菌的量与对照组相比仍降低了约77.1％ （P ＜0.01）,同时参与吞噬活动的RAW264.7细胞的百分比也从71.2％降低到了43.4％ （P ＜0.01）.用脂多糖（LPS,10μg/ml）激活RAW264.7细胞后,其吞噬能力明显增强,而MWCNT仍可剂量依赖性地抑制LPS激活的RAW264.7细胞的吞噬能力,与LPS组相比,MWCNT（75 μg/ml）和LPS共孵育组吞噬大肠杆菌的量降低了70.9％ （P ＜0.01）.结论 MWCNT可明显抑制RAW264.7巨噬细胞的吞噬功能.

Multi-walled Carbon Nanotube Suppresses the Phagocytotic Function of RAW264.7 Macrophages

Objective To observe the effect of multi-walled carbon nanotube （MWCNT） on the phagocytotic function of RAW264.7 macrophages.Methods Flow cytometry was used to quantitatively identify the effect of MWCNT on the phagocytotic activities of RAW264.7 macrophages on FITC-tagged E.coli k-12.Results MWCNT inhibited the phagocytotic activity of RAW264.7 cells in a time-and concentration-dependent manner.Along with the increases of incubation time and MWCNT concentration,the mean fluorescence intensity （MFI） of phagocytosed E.coli inside the RAW264.7 cells decreased,indicating a decrease in the numbers of engulfed E,coli）.In addition,the percentage of RAW264.7 cells participated in the phagocytosis was also reduced by MWCNT.After cells were treated with MWCNT （75 μg/ml） for 12h,the MFI were decreased by 70.4％ （P ＜ 0.01 vs control group）,and the devouring percentage of RAW264.7 cells was decreased from 98.6％ to 92.4％ （P ＜ 0.05）.Incubation of RAW264.7 cells with MWCNT at a lower concentration （25μ g/ml） but a longer time （24 h） also reduced the MFI by 77.1％ （P ＜0.01 vs control group） and the devouring percentage （from 71.2％ to 43.4％,P ＜ 0.01）.When the RAW264.7 cells was activated by LPS （10μg/ml）,MWCNT could still concentration-dependently inhibit the phagocytotic function of RAW264.7 cells,MWCNT at 75μ g/ml reduced the MFI by 70.9％ （P ＜ 0.01 vs LPS alone）.Conclusion MWCNT suppresses the phagocytotic function of RAW264.7 macrophages.