2022, Vol. 26 ›› Issue (31): 4962-4966

Apoptosis of mouse bone marrow-derived macrophages induced by lipopolysaccharide

Zheng Meijie1, Yang Weizhe1, Liu Jialin1, Han Xiangzhen1, 2, Zhou Qiqi1, 2, He Huiyu1, 2   

Abstract: BACKGROUND: Macrophage is an immune defense line in response to external stimuli. The related reaction of any biological material implanted in vivo is related to the immune response mediated by macrophage.  
OBJECTIVE: To investigate the effect of lipopolysaccharide on the apoptosis of bone marrow-derived macrophages in mice.
METHODS:   The bone marrow-derived macrophages of C57BL/6 mice were isolated in vitro and cultured with DMEM containing 0 (control), 10, 100, and 1 000 µg/L lipopolysaccharide for 24 hours. Apoptotic rate was identified by flow cytometry. Hoechst staining was used to observe the cell morphology. RT-PCR was used to detect the mRNA expression levels of interleukin 1, interleukin 6, tumor necrosis factor alpha, and apoptosis-related factors Bax and P53.  
RESULTS AND CONCLUSION: (1) The apoptotic rate of the lipopolysaccharide group at each mass concentration was higher than that of the control group (P < 0.05), and the apoptotic rates of the 100, 1 000 µg/L lipopolysaccharide groups were higher than that of the 10 µg/L lipopolysaccharide group (P < 0.05). (2) Hoechst staining showed that the nucleus of the control group was normal, and the chromatin was concentrated when the cells underwent apoptosis. The cells in the lipopolysaccharide group of various mass concentrations experienced different degrees of apoptosis, and the nuclei of the apoptotic cells were densely stained or fragmented densely stained; the color was slightly whitish, especially at 1 000 µg/L. (3) RT-PCR detection showed that the expression levels of interleukin 1, interleukin 6, tumor necrosis factor α, Bax, and P53 mRNA in the cells of the lipopolysaccharide group of various mass concentrations were higher than those of the control group (P < 0.01 or P < 0.001). With the increased concentration of lipopolysaccharide, the expression levels of interleukin 1, interleukin 6, and tumor necrosis factor α mRNA showed a trend of first increasing and then decreasing, and the expression of Bax and P53 mRNA showed an increasing trend. (4) Results have confirmed that lipopolysaccharide can induce the apoptosis of bone marrow-derived macrophages.
Key words: implant, bone marrow, macrophage, lipopolysaccharide, apoptosis, bone tissue engineering