Abstract:

Abstract 
BACKGROUND: Both high glucose and lipopolysaccharide have been proved to promote the apoptosis of human periodontal ligament fibroblasts (HPLFs), but their interactions on the HPLF apoptosis in vitro have not yet 
been reported.
OBJECTIVE: To investigate the effect of different concentrations of lipopolysaccharide and high glucose on the proliferation, apoptosis and the expression levels of Bax and Bcl-2 in HPLFs in vitro. 
METHODS: The primarily cultured HPLFs were identified. The 5-8 generations of HPLFs were collected and used in the subsequent experiment. The HPLFs were cultured in different concentrations of glucose (5.5 and 25 mmol/L) and lipopolysaccharide (0, 1 and 10 mg/L) for 24 and 48 hours, respectively. 
RESULTS AND CONCLUSION: Lipopolysaccharide (10 mg/L) could significantly inhibit the cell proliferation, promote the cell apoptosis, upregulate the expression levels of Bax and Bcl-2 mRNA and induce a significant decrease in Bcl-2/Bax ratio in the cells cultured with 5.5 mmol/L glucose (P < 0.05). The lipopolysaccharide-induced suppression of cell proliferation, cell apoptosis, the expressions of Bax and Bcl-2 mRNA as well as decrease in Bcl-2/Bax ratio were significantly strengthened in the HPLFs treated with 25 mmol/L glucose (P < 0.05). Analysis of variance found that high glucose and lipopolysaccharide had a significant interaction on the cell apoptosis (P < 0.05). These results reveal that lipopolysaccharide-induced suppression of cell proliferation, cell apoptosis and the expressions of Bax and Bcl-2 mRNA are augmented in HPLFs cultured under high glucose condition, indicating lipopolysaccharide and high glucose interactively act in inducing cell apoptosis.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Lipopolysaccharides, Apoptosis, Tissue Engineering