ABSTRACT
BACKGROUND: Compared with the traditional organic fluorescent dyes, quantum dots present good biomarker characteristics. Especially, quantum dots for cell labeling and targeted bioimaging present unique optical properties.OBJECTIVE: To investigate the biocompatibility of CdSe/ZnS quantum dots with mononuclear macrophages.METHODS: The macrophages RAW264.7 were inoculated into 96-well plates containing 0, 50, 100 mg/L CdSe/ZnS quantum dots for 1 or 2 hours. Then, the fluorescent signal was detected by flow cytometry. After 0-24 hours of culture,the fluorescence signal intensity of the macrophages cultured with 50 mg/L CdSe/ZnS quantum dots was detected by flow cytometry. After 18 hours of culture, quantitative PCR was used to detect the levels of tumor necrosis factor α and interleukin 1β in macrophages, and macrophage proliferation cell apoptosis were detected by MTT and flow cytometry,respectively.RESULTS AND CONCLUSION: The fluorescence signal intensity was positively correlated with the mass concentration of CdSe/ZnS quantum dots, and the intensity of the fluorescent signal was increased with the labeling time. After labeling using 50 mg/L CdSe/ZnS quantum dots, the fluorescence signal of macrophages increased continuously with time, and reached the peak at 18 hours. Compared with 0 mg/L quantum dot group, 50, 100mg/L quantum dot groups could significantly promote the expression of tumor necrosis factor α and interleukin 1β in macrophages (P < 0.01 or P < 0.05).The level of tumor necrosis factor α in the 100 mg/L quantum dot group was higher than that in the 50 mg/L quantum dot group (P < 0.01). The expression of interleukin-1β showed no difference between 50 and 100 mg/L quantum dot groups.The cell proliferation in the 50 and 100 mg/L CdSe/ZnS quantum dot groups was significantly higher than that in the 0 mg/L quantum dot group (P < 0.05), but there was no difference between the former two groups. In addition, 50 and 100 mg/L CdSe/ZnS quantum dots had no significant effect on apoptosis of macrophages. To conclude, CdSe/ZnS quantum dots could activate macrophages and promote their proliferation and secretion of inflammatory factors, but did not affect their apoptosis.
ABSTRACT
Objective:To investigate the effect of butyrate produced by bacterial metabolism on immune features of murine bone marrow-derived dendritic cells(BMDCs) and its potential mechanisms.Methods: BMDCs were prepared from bone marrow cells of C57BL/6 mice by being cultured with GM-CSF and IL-4.The expression of CD80,CD86,B7-DC and MHCⅡ on BMDCs and its pri-ming ability on the proliferation of OVA257-264 antigen specific CD8+T cell were analyzed by using Flow cytometry.The mRNA levels of IL-6 and IL-12 in BMDCs were detected by real-time fluorescence quantitative PCR(q-PCR).Simultaneously,Griess reaction and Western blot was used for analyzing the levels of NO2-in BMDCs culture supernatant and the ERK phosphortylation in BMDCs respectivly.Results:Butyrate could decrease the levels of CD80,CD86,MHCⅡand B7-DC,and downregulate the capability of BMDCs in priming the proliferation of CD8+T cells.Furthermore,the secretions of IL-6,IL-12,NO2-and the phosphorylation of ERK were sup-pressed.Conclusion:Butyrate down-regulats the immune functions of BMDCs via inhibition of ERK phosphorylation in TLR 4 signaling pathway.