Low-energy LED red light inhibits the NF-κB pathway and promotes hPDLSCs proliferation and osteogenesis in a TNF-α environment in vitro.

Abstract

There are few studies on the effect of low-energy LED red light on periodontal tissue regeneration in an inflammatory environment. In this study, Cell Counting Kit-8(CCK-8) assays were used to detect the effects of TNF-α at three different concentrations (0, 10ng/ml, and 20ng/ml) on the proliferation of human periodontal ligament stem cells (hPDLSCs), and 10ng/ml was selected as the subsequent experimental stimulation concentration. CCK-8 assays were used to detect the effect of LED red light with energy density of 1J/ cm2, 3J/ cm2, and 5J/cm2 on the proliferation of hPDLSCs. The promotion effect of energy density of 5J/cm2 on the proliferation of hPDLSCS was the most obvious (p < 0.05). Set CON group, ODM group, ODM + 10ng/ml TNF-α group, and ODM + 10ng/ml TNF-α + 5J/ cm2 LED red light group. Alkaline phosphatase staining and activity detection, alizarin red staining and calcium nodules quantitative detection of osteoblast differentiation products, real-time fluorescence quantitative PCR detection of osteoblast gene expression (Runx2, Col-I, OPN, OCN). The results showed that ODM showed the strongest osteoblast ability, followed by ODM + 10ng/ml TNF-α + 5J/ cm2 LED red light group. The osteoblast ability of ODM + 10ng/ml TNF-α was decreased, but was not found in CON group. Western blot was used to detect the expression of NF-κB pathway protein and osteoblast-related proteins (Runx2, Col-I, OPN, OCN) after addition of PDTC inhibitor. The results showed that the expression of p-IκBα was increased and the expression of IκBα was decreased (p < 0.05). The expression of osteoblast protein increased after the addition of inhibitor (p < 0.05). Therefore, in an inflammatory environment constructed by 10ng/ml TNF-α, 5J/cm2 LED red light can upregulate the proliferation and osteogenesis of hPDLSCs by inhibiting NF-κB signaling pathway.