脂多糖/氨基半乳糖(LPS/D-GalN)体外诱导肝细胞损伤模型的建立和评价

Establishment and evaluation of hepatocyte injury model induced by LPS/D-galactosamine in vitro

目的建立脂多糖/D-氨基半乳糖(LPS/D-GalN)体外诱导肝细胞损伤模型.方法体外培养小鼠原代肝细胞,待其稳定贴壁生长后,加入(0.1、0.5、1、5)ng/mL肿瘤坏死因子α(TNF-α)和5 mg/mL D-GalN进行处理,全自动生化分析仪检测细胞上清丙氨酸氨基转移酶(ALT)活性反映肝细胞损伤.诱导骨髓来源巨噬细胞成熟,通过1μg/mL LPS刺激巨噬细胞产生TNF-α;巨噬细胞培养上清联合5 mg/mL D-GalN或50 ng/mL放线菌素D(ActD)处理原代肝细胞24 h,检测ALT活性、显微镜观察细胞损伤情况.原代肝细胞和骨髓来源巨噬细胞(BMDM)共培养,LPS联合D-GalN或ActD对共培养体系处理24h,检测共培养细胞上清ALT活性、显微镜观察细胞损伤情况.结果TNF-α和D-GalN联合处理原代肝细胞,细胞培养上清ALT活性升高,表明肝细胞发生损伤.LPS刺激BMDM表达TNF-α明显增加,BMDM上清联合D-GalN能引起肝细胞培养上清ALT活性升高和肝细胞皱缩、破碎.肝细胞和BMDM共培养体系中,LPS联合D-GalN能够引起肝细胞损伤;但LPS联合ActD不能引起肝细胞损伤,显微镜观察发现巨噬细胞大量变圆、皱缩,提示巨噬细胞早于肝细胞发生死亡.结论LPS/D-GalN能在体外诱导肝细胞损伤;在利用BMDM和原代肝细胞共培养体系评价损伤效应时,应当用D-GalN而不是ActD作为转录抑制剂.

Objective To establish a novel hepatocyte injury model induced by lipopolysaccharide/D-galactosamine(LPS/D-GalN) in vitro. Methods Freshly isolated mouse primary hepatocytes were cultured in vitro and treated with different doses of tumor necrosis factor-α(TNF-α) and 5 mg/mL of D-GalN. The supernatants from hepatocyte culture were detected for alanine aminotransferase(ALT) activity by chemiluminescence assay. Bone marrow-derived macrophages(BMDMs) were stimulated with 1 μg/mL of LPS and the level of TNF-α in supernatants were detected by ELISA. Primary hepatocytes were treated with the BMDM supernatants combined with 5 mg/mL D-GalN or 50 ng/mL actinomycin D(ActD) for 24 hours. The level of ALT from hepatocyte supernatant was detected and morphology of hepatocytes was observed with microscopy. BMDMs and hepatocytes were co-cultured and treated with 1 μg/mL of LPS combined with D-GalN or ActD for 24 hours. Hepatocyte injury was reflected by the ALT activity and hepatocyte morphology. Results The ALT activity was significantly increased in the supernatants of hepatocytes treated with TNF-α and D-GalN, indicating the obvious hepatocyte injury. Co-treatment with LPS-primed BMDM supernatants and D-GalN or ActD could cause hepatocyte injury, as reflected by markedly increased ALT activity and the deformed and cracked hepatocytes. In the context of co-culture of BMDM and hepatocytes, treatment with LPS and D-GalN led to obvious hepatocyte injury as expected. LPS combined with ActD could not cause hepatocyte injury, since the BMDMs started to die earlier than they could secret TNF-α to destruct hepatocytes. Hepatocytes with normal morphology and deformed BMDMs were observed. Conclusion LPS/D-GalN can be used to induce hepatocyte injury in vitro. D-GalN, rather than ActD, should be used as a transcriptional inhibitor when the TNF-α-induced hepatocyte injury is evaluated in a co-culture system of BMDMs and hepatocytes.