College of Materials Science and Chemical Engineering, Zhejiang University, Zhejiang 310027, PR China.
Toxicol Appl Pharmacol. 2012 Jan 1;258(1):19-25. doi: 10.1016/j.taap.2011.10.020. Epub 2011 Nov 6.
Troglitazone, despite passing preclinical trials on animals, was shortly withdrawn from market due to its severe hepatotoxicity in clinic. As rat hepatocyte monolayer consistently showed sensitive troglitazone toxicity as human hepatocyte monolayer in contrast to the species-specific toxicity in vivo, this paper utilized both hepatocytes in three-dimensional culture of gel entrapment to reflect the species difference on hepatotoxicity. Rat hepatocytes in gel entrapment did not show obvious cellular damage even under a long-term exposure for 21 days while gel entrapped human hepatocytes significantly displayed oxidative stress, steatosis, mitochondrial damage and cell death at a short exposure for 4 days. As a result, the detected species-specific toxicity of troglitazone between gel entrapped rat and human hepatocytes consisted well with the situation in vivo but was in a sharp contrast to the performance of two hepatocytes by monolayer culture. Such contradictory toxicity of rat hepatocytes between monolayer and gel entrapment culture could be explained by the fact that troglitazone was cleared more rapidly in gel entrapment than in monolayer culture. Similarly, the differential clearance of troglitazone in rat and human might also explain its species-specific toxicity. Therefore, gel entrapment of hepatocytes might serve as a platform for evaluation of drug toxicity at early stage of drug development by reducing costs, increasing the likelihood of clinical success and limiting human exposure to unsafe drugs.
曲格列酮虽然在动物的临床前试验中通过了检测，但由于其在临床上具有严重的肝毒性，很快就被撤出市场。由于大鼠肝细胞单层在体外对曲格列酮的毒性比体内的种属特异性毒性更为敏感，与人类肝细胞单层相比，本文利用凝胶包埋的三维培养中的两种肝细胞来反映种属差异对肝毒性的影响。即使在长达 21 天的长期暴露下，凝胶包埋的大鼠肝细胞也没有明显的细胞损伤，而凝胶包埋的人肝细胞在 4 天的短期暴露下则明显显示出氧化应激、脂肪变性、线粒体损伤和细胞死亡。因此，凝胶包埋的大鼠和人肝细胞中检测到的曲格列酮的种属特异性毒性与体内情况相符，但与单层培养的两种肝细胞的表现形成鲜明对比。凝胶包埋培养的大鼠肝细胞与单层培养的大鼠肝细胞之间存在这种矛盾的毒性，可能是因为曲格列酮在凝胶包埋中的清除速度比在单层培养中更快。同样，曲格列酮在大鼠和人类中的清除差异也可能解释其种属特异性毒性。因此，通过降低成本、提高临床成功率和限制人类接触不安全药物，肝细胞的凝胶包埋可能成为药物开发早期药物毒性评估的平台。
