Expression of cell cycle proteins and PARP after PH. PCNA, cyclin D1, p21 and PARP in the remaining liver were analyzed by western blot analysis after PH. β-actin was used as loading control. Cyclin-D1 expression was increased as early as 3 hours and remained at the higher levels in IL-6 KO mice after PH. In contrast, there is no increased expression of cyclin-D1 in WT mice until 24 hour after PH. PCNA expression was significantly increased in IL-6 KO mice at 24 hours after PH. However, there is no increased expression of PCNA in WT mice at 24 hours after PH. The expression of cell cycle inhibitor, p21, was significantly higher in WT mice at 6 or 24 hours after HP compared to IL-6 KO mice. Almost no p21 expression was present in IL-6-KO mice at 24 hours after PH. Full length PARP (116 kDa) expression was decreased in IL-6 KO mice compared to WT mice at 6, 12, and 24 hours after PH. Representative data of 3 or 4 individual samples per group.