胰岛素样生长因子结合蛋白2、4在实验性肝细胞损伤中的表达及意义

目的：通过观察肿瘤坏死因子α (TNF -α)和转化生长因子β1（TGF-β1）两种细胞因子所致体外培养的肝细胞损伤时胰岛素样生长因子结合蛋白2、4(IGFBP2、IGFBP4)的表达变化，探讨IGFBP2和IGFBP4在肝损伤中的作用机制。方法：对人肝细胞株HL-7702分别给予不同浓度的TNF-α、TGF-β1两种处理因素作用24 h，采用免疫细胞化学染色法观察其IGFBP2和IGFBP4的表达变化，再在相同处理培养条件下用MTT比色法检测两种细胞因子对肝细胞抑制率的影响。根据MTT及预实验结果选择TNF-α 20 μg/L作用于人肝细胞株48h，采用Annexin-Ⅴ/PI双染色流式细胞分析法和TUNEL法检测肝细胞凋亡发生率。结果：与对照组相比，各处理组IGFBP2、IGFBP4的表达均显著增加(P<0.05)，其中在TNF-α 20 μg/L组和TGF-β1 4 μg/L组表达最强，且与肝细胞抑制率呈正相关关系(P<0.05 or P<0.01)。TNF-α 20 μg/L处理48 h后肝细胞凋亡率明显增加(P<0.01)。结论：IGFBP2、IGFBP4参与了肝细胞的损伤过程，在TNF-α、TGF-β1介导的肝细胞损伤中具有重要作用。

Expression of IGFBP2 and IGFBP4 in hepatocytes with experimental injury

AIM:To explore the mechanism of IGFBP2 and IGFBP4 in hepatocytes with injury induced by TNF-α and TGF-β1. METHODS:Human hepatocyte line (HL-7702) was cultured in vitro and treated with TNF-α or TGF-β1 for 24 h. The expression of IGFBP2 and IGFBP4 was detected by immunochemistry staining. The inhibition ratio of hepatocytes was detected by MTT assay. HL-7702 was treated with TNF-α at concentration of 20 μg/L for 48 h, then the apoptosis of hepatocytes was detected by both Annexin-V /PI and TUNEL assay. RESULTS:The expression of IGFBP2 and IGFBP4 in TNF-α or TGF-β1 treated groups was significantly higher than that in control group (P<0.05). The positive staining of IGFBP2 and IGFBP4 in TNF-α (20 μg/L) treated groups or TGF-β1 (4 μg/L) treated groups was the strongest among all groups. A positive correlation was found between IGFBP2 or IGFBP4 and inhibitory ratio of hepatocytes (P<0.05 or P<0.01). Compared with normal control group, the percentage of apoptosis markedly increased in TNF-α (20 μg/L) treated group (P<0.01). CONCLUSION:IGFBP2 and IGFBP4 involved in the injury process in hepatocytes, indicating an important role in injury of hepatocytes induced by TNF-α or TGF-β1.