Imanishi H, Kothary P C, Bhora F Y, Eckhauser F E, Raper S E
Department of Surgery, University of Michigan Medical School, Ann Arbor 48109, USA.
J Surg Res. 1995 Apr;58(4):435-40. doi: 10.1006/jsre.1995.1068.
Cirrhotic livers are considered to regenerate less actively than normal livers after hepatic resection. Little is known about the mechanisms responsible for impaired capacity of regeneration in cirrhotic liver. In the present study, we investigated the effect of phorbol ester on hepatocyte proliferation in healthy and cirrhotic hepatocytes, using one of the phorbol esters, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which has a direct effect on activation of protein kinase C (PKC). Cirrhosis was established by the administration of carbon tetrachloride and phenobarbital to rats. Healthy and cirrhotic hepatocytes were isolated from Wistar male rats by a two-step collagenase perfusion technique. DNA synthesis was estimated by [3H]thymidine incorporation into DNA and by autoradiographic nuclear labeling index. [3H]Thymidine incorporation was measured 24 hr after hepatocytes were stimulated by appropriate reagents. TPA (50 nM) stimulated [3H]thymidine incorporation in healthy hepatocytes (control vs TPA, 991 +/- 247 vs 2569 +/- 766 mean +/- SEM cpm/microgram DNA; P < 0.05), whereas TPA (50 nM) failed to stimulate in cirrhotic hepatocytes (control vs TPA, 1144 +/- 184 vs 1304 +/- 187 cpm/microgram DNA; NS). Staurosporine, a specific PKC inhibitor, suppressed [3H]thymidine incorporation in TPA-stimulated healthy hepatocytes (806 +/- 263 cpm/microgram DNA; P < 0.05); however, it had no effect on cirrhotic hepatocytes (1295 +/- 180 cpm/microgram DNA; NS). An autoradiographic nuclear labeling index exhibited the same results with [3H]thymidine incorporation. We conclude that TPA stimulates hepatocyte proliferation in healthy rat hepatocytes but has no effect on cirrhotic hepatocytes.
肝硬化肝脏在肝切除术后被认为比正常肝脏的再生活性更低。关于肝硬化肝脏再生能力受损的机制知之甚少。在本研究中，我们使用佛波酯之一的12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA），研究了佛波酯对健康和肝硬化肝细胞中肝细胞增殖的影响，TPA对蛋白激酶C（PKC）的激活有直接作用。通过给大鼠注射四氯化碳和苯巴比妥建立肝硬化模型。采用两步胶原酶灌注技术从Wistar雄性大鼠中分离出健康和肝硬化肝细胞。通过[3H]胸腺嘧啶核苷掺入DNA以及放射自显影核标记指数来估计DNA合成。在肝细胞用适当试剂刺激24小时后测量[3H]胸腺嘧啶核苷掺入量。TPA（50 nM）刺激健康肝细胞中的[3H]胸腺嘧啶核苷掺入（对照组与TPA组，平均±标准误cpm/μg DNA分别为991±247与2569±766；P < 0.05），而TPA（50 nM）未能刺激肝硬化肝细胞（对照组与TPA组，cpm/μg DNA分别为1144±184与1304±187；无显著性差异）。特异性PKC抑制剂星形孢菌素抑制TPA刺激的健康肝细胞中的[3H]胸腺嘧啶核苷掺入（806±263 cpm/μg DNA；P < 0.05）；然而，它对肝硬化肝细胞没有影响（1295±180 cpm/μg DNA；无显著性差异）。放射自显影核标记指数与[3H]胸腺嘧啶核苷掺入呈现相同结果。我们得出结论，TPA刺激健康大鼠肝细胞中的肝细胞增殖，但对肝硬化肝细胞没有影响。
