Medicines are usually prescribed for repeated use over shorter or longer times. Unfortunately, repeated-dose animal toxicity studies do not correlate well with observations in man. As emphasized by the ‘3Rs’ and the desire to phase-out animal research, in vitro models are needed. One potential approach uses clinostat-cultured 3D HepG2–C3A liver-mimetic spheroids. They take 18 days to recover in vivo physiological functionality and reach a metabolic equilibrium, which is thereafter stable for a year. Acute and chronic repeated-dose studies of six drugs (amiodarone, diclofenac, metformin, phenformin, paracetamol and valproic acid) suggest that spheroids are more predictive of human in vivo toxicity than either 2D-cultured HepG2 cells or primary human hepatocytes. Repeated non-lethal treatment results in a clear response and return to equilibrium. Mitochondrial toxic compounds can be identified using a galactose-based medium. Some drugs induced a protective (or stress) response that intensifies after the second treatment. This 3D spheroid model is inexpensive, highly reproducible and well-suited for the determination of repeated-dose toxicity of compounds (naturally or chemically synthesized).

中文翻译：

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对人类模拟肝的类球体球状体的反应以及从治疗中恢复：评估重复剂量药物毒性的模型。

通常开出处方，规定在较短或更长时间内重复使用药物。不幸的是，重复剂量的动物毒性研究与人的观察结果并没有很好的关联。正如“ 3R”所强调的以及逐步淘汰动物研究的愿望一样，需要体外模型。一种可能的方法是使用由clinostat培养的3D HepG2-C3A仿肝球体。它们需要18天才能恢复体内的生理功能并达到代谢平衡，此后稳定一年。急性和的6种药物（胺碘酮，双氯芬酸，二甲双胍，苯乙双胍，对乙酰氨基酚和丙戊酸）慢性重复剂量研究表明，球状体是多个预测人类的体内毒性高于2D培养的HepG2细胞或原代人肝细胞。反复进行非致死性治疗会产生明确的反应并恢复至平衡。线粒体有毒化合物可以使用基于半乳糖的培养基进行鉴定。一些药物引起的保护性（或应激性）反应在第二次治疗后加剧。该3D球体模型价格便宜，可重复性很高，非常适合确定化合物（天然或化学合成）的重复剂量毒性。