Effect of naringin combined with bone morphogenetic protein-2 on the proliferation and differentiation of MC3T3-E1 cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study evaluates the biological effects of naringin (NAR) joint bone morphogenetic protein (BMP)-2 on the proliferation, alkaline phosphatase (ALP) activity, and expression of osteoblastogenic genes, such as Runt-related transcription factor 2 (Runx2), collagen Ⅰ (ColⅠ), ALP, and osteocalcin (OCN) of pre-osteoblasts.</p><p><b>METHODS</b>Three different NAR concentrations (10, 100, and 1 000 μmol·L⁻¹) were applied, alone or combined with BMP-2(50 ng·mL⁻¹), to restore the osteoblastogenesis of pre-osteoblasts (MC3T3-E1 cell line). Cell numbers (proliferation) were evaluated at first, fourth, and seventh days by Alamar blue assay. ALP activity and the expression of osteoblastogenic genes, such as Runx2, ColⅠ, ALP, and OCN were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) at fourth and seventh day.</p><p><b>RESULTS</b>Stimulation by NAR alone and in combination with BMP-2 for 1 day and 4 days could promote cell proliferation, which peaked at a concentration of 100 μmol·L⁻¹ NAR combined with BMP-2 could promote cell proliferation significantly (P<0.05). Stimulation by NAR alone and in combination with BMP-2 for 4 and 7 days could promote ALP activity and bone-related gene(ALP, OCN, Runx2, ColⅠ) expression. ALP expression was significantly promoted after stimulation of 100 μmol·L⁻¹ NAR and BMP-2 (P<0.05).</p><p><b>CONCLUSIONS</b>NAR exhibits promising potential for improving MC3T3-E1 proliferation and differentiation, and appropriate concentrations of NAR and BMP-2 show synergistic effect.
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Research progress of mechanism of hypoxia-inducible factor-1α signaling pathway in condylar cartilage growth and remodeling / 华西口腔医学杂志

The condylar cartilage was adapted to hypoxic conditions in vivo. However, condylar cartilage cells exposed in normoxia in vitro affect the chondrocyte phenotype and cartilage matrix formation. This condition also resulted in great difficulty in chondrocyte research. Culturing chondrocyte should be simulated in in vivo hypoxia environment as much as possible. The hypoxia-inducible factor-1α (HIF-1α) demonstrates an important transcription factor of adaptive response to hypoxic conditions. HIF-1α also plays an active role in maintaining homeostasis and function of chondrocytes. This review summarized current knowledge of the HIF-1α structure, signaling pathway, and mechanism of HIF-1α in the condylar cartilage repair.