人牙周膜成纤维细胞凋亡与体外高糖环境和脂多糖的交互作用

Interaction of high glucose and lipopolysaccharide on the apoptosis of human periodontal ligament fibroblasts in vitro

背景:已有研究表明,高糖和脂多糖在单独作用下都能够促进人牙周膜成纤维细胞的凋亡,但体外培养的人牙周膜成纤维细胞在高糖和脂多糖共同作用下的凋亡行为尚未有相关报道。目的:通过不同浓度脂多糖影响高糖环境下人牙周膜成纤维细胞,观察细胞增殖、凋亡以及凋亡相关基因Bax和Bcl-2表达的变化。方法:原代培养并鉴定人牙周膜成纤维细胞,5-8代用于后继实验。分别用葡萄糖(5.5,25 mmol/L)和脂多糖(0,1,10 mg/L)作用于细胞24 h及48 h。结果与结论:(1)在正常的葡萄糖浓度(5.5 mmol/L)下,质量浓度为10 mg/L的脂多糖能够显著抑制细胞的增殖(P<0.05),促进细胞的凋亡(P<0.05),Bax和Bcl-2 mR NA表达增强(P<0.05),Bcl-2/Bax的比值显著降低(P<0.05);(2)在高糖浓度(25 mmol/L)下,脂多糖诱导的细胞增殖的抑制、细胞凋亡、Bax和Bcl-2 mR NA的表达以及Bcl-2/Bax比值的降低都显著增强(P<0.05);(3)方差分析结果显示,高糖和脂多糖在诱导细胞凋亡方面有显著的交互作用(P<0.05);(4)结果说明,脂多糖在高糖环境下介导的人牙周膜成纤维细胞增殖的抑制、凋亡及凋亡相关基因Bax和Bcl-2的表达显著增强,脂多糖和高糖在细胞凋亡方面有显著的交互作用。

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 yetbeen 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 m RNA 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 m RNA 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 m RNA are augmented in HPLFs cultured under high glucose condition, indicating lipopolysaccharide and high glucose interactively act in inducing cell apoptosis.