Effects of LPS-stimulated monocyte culture supernatant on the osteogenic function of osteoblastic cells in vitro

Abstract

Objective To investigate the influence of Pg-LPS stimulated monocyte (RAW264.7) culture supernatant on the proliferation and alkaline phosphatase (ALP) activity of osteoblastic cells (MC3T3-E1) in vitro. Methods The culture supernatant of monocytes stimulated with Pg-LPS was applied to osteoblasts MC3T3-E1 with different diluted concentrations(10%、20%、30%、40% and 50%) simultaneously for 24 h and 48 h in vitro.The cellular proliferation was assessed by MTT assay, Cellular ALP activity was examined using ALP measurement kit, and the results were statistically analyzed using SPSS 12.0 software package. Results LPS stimulated RAW264.7 to release inflammatory cytokines including IL-1β, IL-6 and TNF-α, whose secretion was in a time and dose dependent manner with the concentration of LPS. After the stimulation of different concentrations of inflammatory supernatant, the proliferation and ALP activity of MC3T3-El cells significantly deceased, both in a concentration-dependent manner. Conclusions These results indicated that the inflammatory cytokine secretion of Pg-LPS stimulated RAW264.7 culture supernatant was similar to the change in vivo with inflammation. The inflammatory supernatant could inhibit the proliferation and ALP activity of osteoblastic cells. Key words: LPS; Monocyte; Osteoblasts; Proliferation; ALP activity