Abstract:

Objective To discuss the effect of honeysuckle extract on the proliferation and apoptosis of airway smooth muscle cells （ASMCs） in the asthmatic mice，and to clarify the related mechanism. Methods The asthma models of mice were constructed， and the primary ASMCs were isolated and identified. The M2 polarization of macrophages RAW264.7 was induced and identified. The RAW264.7 cells were divided into control group， low， medium and high doses of honeysuckle extract groups. The RAW264.7 cells in control group were induced M2 polarization and co-cultured with ASMCs. The RAW264.7 cells in low， medium， and high doses of honeysuckle extract groups were treated with different concentrations （50， 100， and 200 mg·L^－1） of honeysuckle extract for 1 h and then treated with interleukin-4 （IL-4） （60 μg·L^－1） for 6 h. Then the RAW264.7 cells and ASMCs were co-cultured for 24 h. The percentages of CD86 and CD206 positive cells in various groups were detected by flow cytometry； the levels of interleukin-10（IL-10） in culture supernatant of the ASMCs in various groups were detected by enzyme-linked immunosorbent assay （ELISA） method； the proliferation activities of cells in various groups were detected by MTT assay； the apoptotic rates of ASMCs in various groups were detected by flow cytometry. Results The morphology of the cells and immunofluorescence staining results proved that the extracted cells were the ASMCs.The M2 polarization identification results showed that the RAW264.7 cells were induced into the M2 macrophages.Compared with control group， the percentages of CD86 positive cells in the ASMCs in low， medium and high doses of honeysuckle extract groups were significantly increased （P<0.05），while the percentages of CD206 positive cells were decreased（P<0.05）；the IL-10 levels in culture supernatant of the ASMCs and the proliferation activities of ASMCs were significantly decreased （P<0.05），and the apoptotic rates of the ASMCs were increased（P<0.05）. Compared with low dose of honeysuckle extract group， the percentages of CD86 positive cells in medium and high doses of honeysuckle extract groups were significantly increased（P<0.05）， while the percentages of CD206 positive cells were decreased（P<0.05）；the IL-10 levels in the culture supernatant and proliferation activities of the cells were significantly decreased （P<0.05），and the apoptotic rates of the ASMCs were increased（P<0.05）.Compared with medium dose of honeysuckle extract group， the percentages of CD86 positive cells in high dose of honeysuckle extract group was significantly increased（P<0.05）， while the percentage of CD206 positive cells was decreased（P<0.05）； the IL-10 levels in the culture supernatant and proliferation activities of the cells were significantly decreased （P<0.05），and the apoptotic rates of the ASMCs were increased（P<0.05）. Conlusion： Honeysuckle extract can inhibit the proliferation and promote the apoptosis of the ASMCs in the asthmatic mice by inhibiting the M2 polarization of the macrophages.

Key words: Asthma, Honeysuckle extract, Airway smooth muscle cells, Cell proliferation, Apoptosis