Utanohara Shinichi, Tsuji Mayumi, Momma Shusuke, Morio Yuri, Oguchi Katsuji
Department of Pharmacology, School of Medicine, Showa University, Hatanodai 1-5-8, Tokyo 142-8555, Japan.
Toxicology. 2005 Oct 15;214(1-2):77-86. doi: 10.1016/j.tox.2005.05.025.
Ursodeoxycholic acid (UDCA) has been widely used for treating cholestatic liver diseases. However, in a recent review of clinical trial articles, its therapeutic benefits were not proven. Therefore, we investigated whether UDCA prevents or potentiates glycochenodeoxycholic acid (GCDCA)-induced apoptosis in isolated rat hepatocytes. Hepatocellular cytotoxicity was assessed by lactate dehydrogenase (LDH) release, and apoptosis evaluated by DNA fragmentation, caspase activities, release of cytochrome C from mitochondria, and mitochondrial membrane potential change (Deltapsi). When hepatocytes were co-incubated with GCDCA and UDCA for a short time (2-6 h), GCDCA-induced LDH release was significantly reduced, while prolonged co-incubation (12-20 h) increased it. Similarly, the same co-incubation for a short time resulted in the inhibition of caspase activities and cytochrome C release, while prolonged incubation enhanced them compared with the incubation with GCDCA alone. Furthermore, UDCA significantly promoted the GCDCA-induced Deltapsi decline after 4h of incubation. These results demonstrated that UDCA reduced GCDCA-induced apoptosis in short incubation, but potentiated it in prolonged incubation. Based on these, we propose a hypothesis that induction of Deltapsi decrease from earlier stage of incubation may be responsible for the aggravation of GCDCA-induced apoptosis in long-term exposure, and would like to raise caution about clinical long-term use of UDCA.
熊去氧胆酸（UDCA）已被广泛用于治疗胆汁淤积性肝病。然而，在最近对临床试验文章的综述中，其治疗益处并未得到证实。因此，我们研究了UDCA是否能预防或增强甘氨鹅脱氧胆酸（GCDCA）诱导的离体大鼠肝细胞凋亡。通过乳酸脱氢酶（LDH）释放评估肝细胞毒性，通过DNA片段化、半胱天冬酶活性、细胞色素C从线粒体的释放以及线粒体膜电位变化（ΔΨ）评估凋亡。当肝细胞与GCDCA和UDCA短期共同孵育（2 - 6小时）时，GCDCA诱导的LDH释放显著降低，而延长共同孵育时间（12 - 20小时）则使其增加。同样，短期相同的共同孵育导致半胱天冬酶活性和细胞色素C释放受到抑制，而与单独用GCDCA孵育相比，延长孵育则增强了这些作用。此外，孵育4小时后，UDCA显著促进了GCDCA诱导的ΔΨ下降。这些结果表明，UDCA在短期孵育时可减少GCDCA诱导的凋亡，但在延长孵育时会增强这种凋亡。基于这些，我们提出一个假设，即孵育早期阶段ΔΨ下降的诱导可能是长期暴露时GCDCA诱导的凋亡加剧之原因，并希望对UDCA的临床长期使用提出警示。
