Harbin Medical University, Harbin, China.
Eur Rev Med Pharmacol Sci. 2018 Mar;22(6):1569-1579. doi: 10.26355/eurrev_201803_14561.
To investigate the effect of low-concentration lipopolysaccharide (LPS) on proliferation and apoptosis of osteoblasts and to discover the mechanism of low-concentration LPS in facilitating the proliferation of osteoblasts.
MC3T3-E1 osteoblasts were treated with LPS, 3-methyladenine (3-MA, autophagy inhibitor), and BAY11-7082 (inhibitor of nuclear factor-kappa b, NF-κB), respectively. The cell cycles were detected using a flow cytometer. Cell proliferation and activity of MC3T3-E1 osteoblasts were explored by cell counting kit-8. Western blotting and immunofluorescence assay were performed to detect the protein level. RNA expression was measured through polymerase chain reaction (PCR) and immunofluorescence assay.
At the third day after cell culture, cell infusion reached 80%, and cells were taken as the subjects. At 6 h after treatment with low-concentration LPS, the proliferation and activity of cells were higher than those at 1 h and 12 h after treatment, and the apoptotic level was significantly lower than that in cells at 12 h after treatment. The proliferation and activity of cells in the low-concentration LPS group were significantly higher than those in the control group, 3-MA group and BAY11-7082 group, and the apoptotic level was lower than those in these groups. Compared with those of cells in control group and BAY11-7082 group, the messenger RNA (mRNA) and protein expressions and nuclear transfer of cells in low-concentration LPS group were significantly elevated, but there were no statistically significant differences in comparisons with the 3-MA group. In the experiment of cell autophagy, the autophagic level in cells in low-concentration LPS group was higher than those in the control group, 3-MA group and BAY11-7082 group.
Through the NF-κB signaling pathway in osteoblasts, low-concentration LPS can activate the autophagy and promote cell proliferation, thereby inhibiting cell apoptosis and accelerating the fracture healing.
研究低浓度脂多糖（LPS）对成骨细胞增殖和凋亡的影响，探讨低浓度 LPS 促进成骨细胞增殖的作用机制。
分别用 LPS、3-甲基腺嘌呤（3-MA，自噬抑制剂）和 BAY11-7082（核因子-κB 抑制剂）处理 MC3T3-E1 成骨细胞，用流式细胞仪检测细胞周期。用细胞计数试剂盒-8 检测 MC3T3-E1 成骨细胞的增殖和活性。用 Western blot 和免疫荧光法检测蛋白水平。通过聚合酶链反应（PCR）和免疫荧光法测量 RNA 表达。
细胞培养第 3 天，细胞融合率达到 80%，取此时的细胞作为研究对象。低浓度 LPS 处理 6 h 后，细胞的增殖和活性均高于处理 1 h 和 12 h 时，凋亡水平明显低于处理 12 h 时。低浓度 LPS 组细胞的增殖和活性明显高于对照组、3-MA 组和 BAY11-7082 组，凋亡水平低于这三组。与对照组和 BAY11-7082 组相比，低浓度 LPS 组细胞的信使 RNA（mRNA）和蛋白表达及核转移明显升高，但与 3-MA 组相比差异无统计学意义。在细胞自噬实验中，低浓度 LPS 组细胞的自噬水平高于对照组、3-MA 组和 BAY11-7082 组。
通过成骨细胞中的 NF-κB 信号通路，低浓度 LPS 可以激活自噬，促进细胞增殖，从而抑制细胞凋亡，加速骨折愈合。
