ABSTRACT
Objective@#To analyze the immune responses of bone-marrow derived macrophages and osteoclasts to lipopolysaccharide from Porphyromonas gingivalis (Pg-LPS) so as to provide reference for host immunomodulatory therapy of periodontitis.@*Methods@#Bone marrow mononuclear cells from C57BL/6 mice were obtained and induced into bone marrow macrophages (BMM) and osteoclasts (OC) by conditioned medium. The BMMs and OCs were divided into blank control group and Pg-LPS treated experimental group. Pg-LPS (10 μg/ml) was used to stimulate BMM and OC. The mRNA and protein expression of TLR-2 and TLR-4 and secretion of inflammatory cytokines were detected, respectively. Furthermore, the effect of Pg-LPS on the differentiation of BMM into OC was evaluated.@*Results@#Mouse bone marrow mononuclear cells were successfully induced into BMM and mature OC. In the presence of Pg-LPS, the gene level of TLR-2 in BMM was significantly up-regulated by (41.41±13.07) folds (P<0.01), while the level of TLR-4 mRNA was not significantly changed. TLR-2 mRNA and TLR-4 mRNA levels in OC increased by (2.24±0.23) times (P<0.05) and (4.83±1.07) times (P<0.01), respectively. Flow cytometry results showed that TLR-2 protein expression in BMM was robustly enhanced (P<0.01), as mean fluorescence intensities (MFI) were (39.85±5.27) in blank group and (221.57±13.13) in experimental group, respectively. The MFI of TLR-2 in OC also increased as (83.31±2.69) in blank group and (108.65±6.32) in experimental group, respectively (P<0.01). However, no significant TLR-4 expressions were observed in both BMM and OC (P>0.05). Moreover, the productions of tumor necrosis factor-α and interleukin-6 in response to LPS in BMM and OC remarkably increased (P<0.01). Lower cytokine expression was observed in OC than that in BMM (P<0.01). In addition, Pg-LPS obviously inhibited the number and size of OC formation, with a reduction in area percentage of approximately 47%.@*Conclusions@#Pg-LPS generated a robust immune inflammatory response to BMM, while OC had a relatively weaker immune response to the Pg-LPS. Pg-LPS might inhibite the differentiation of BMM into OC.