Traiser M, Diener B, Utesch D, Oesch F
Institute of Toxicology, University of Mainz, Germany.
In Vitro Cell Dev Biol Anim. 1995 Apr;31(4):266-73. doi: 10.1007/BF02634000.
In primary monocultures of adult rat liver parenchymal cells (PC), the activities of the xenobiotic metabolizing enzymes microsomal epoxide hydrolase (mEHb), soluble epoxide hydrolase (sEH), glutathione S-transferases (GST), and phenolsulfotransferase (ST) were reduced after 7 d to values below 33% of the initial activities. Furthermore, the gap junctional intercellular communication (GJIC), measured after microinjection by dye transfer, decreased from 90% on Day 1 to undetectable values after 5 d in monoculture. Co-culture of PC with nonparenchymal rat liver epithelial cells (NEC) increased (98% on Day 1) and stabilized (82% on Day 7) the homotypic GJIC of PC. Additionally, most of the measured xenobiotic metabolizing enzyme activities were well stabilized over 1 wk in co-culture. Because GJIC is one of several mechanisms playing an important role in cell differentiation, the importance of GJIC for the stabilization of xenobiotic metabolizing enzymes in PC was investigated. PC in monoculture were, therefore, treated with 2% dimethyl sulfoxide (DMSO), a differentiation promoting factor, and 1,1,1-trichloro-2,2,-bis (p-chlorophenyl) ethane (DDT) (10 micrograms/ml), a liver tumor promotor and inhibitor of GJIC, was given to co-cultures of PC with NEC. DMSO significantly stabilized (68% on Day 7), while DDT significantly inhibited (8% on Day 7) homotypic GJIC of PC in the respective culture systems. In contrast, the activities of mEHb, sEH, GST, and ST were not affected in the presence of DMSO or DDT. These results lead to the assumption that the differentiation parameters measured in this study (i.e., homotypic GJIC and the activities of xenobiotic metabolizing enzymes) are independently regulated in adult rat liver PC.
在成年大鼠肝实质细胞（PC）的原代单培养中，7天后，异生物代谢酶微粒体环氧化物水解酶（mEHb）、可溶性环氧化物水解酶（sEH）、谷胱甘肽S-转移酶（GST）和酚磺基转移酶（ST）的活性降低至初始活性的33%以下。此外，通过染料转移显微注射测量的间隙连接细胞间通讯（GJIC），在单培养中从第1天的90%降至5天后无法检测到的值。PC与非实质大鼠肝上皮细胞（NEC）共培养可增加（第1天为98%）并稳定（第7天为82%）PC的同型GJIC。此外，在共培养中，大多数测量的异生物代谢酶活性在1周内得到很好的稳定。由于GJIC是在细胞分化中起重要作用的几种机制之一，因此研究了GJIC对PC中异生物代谢酶稳定的重要性。因此，单培养中的PC用2%二甲基亚砜（DMSO）处理，DMSO是一种分化促进因子，而1,1,1-三氯-2,2-双（对氯苯基）乙烷（DDT）（10微克/毫升），一种肝肿瘤促进剂和GJIC抑制剂，给予PC与NEC的共培养物。DMSO在各自的培养系统中显著稳定（第7天为68%），而DDT显著抑制（第7天为8%）PC的同型GJIC。相反，在存在DMSO或DDT的情况下，mEHb、sEH、GST和ST的活性不受影响。这些结果导致这样的假设，即在本研究中测量的分化参数（即同型GJIC和异生物代谢酶的活性）在成年大鼠肝PC中是独立调节的。
