Fig. 2. Effect of remifentanil preconditioning on liver ischemia reperfusion injury (n = 10 in each group). (A ) Hepatic tissue histologic changes were processed with hematoxylin and eosin (H&E) staining for light microscopy examination. Photograph depicts typical pattern of focal necrosis (black arrows ) after ischemic degeneration of hepatocytes around the central venous area. Hepatocyte apoptosis was determined by immunohistochemical analysis by microscopy after terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining. Photograph depicts typical pattern of apoptotic cells (black arrows ). (B ) Areas of necrosis were significantly decreased in all remifentanil-pretreated groups than in ischemia-reperfusion group (IR) (*P < 0.05 vs. IR). Magnification: 200×. Scale bar = 200 μm. (C ) Percentage of apoptotic cells was significantly lower in 2 μg · kg−1· min−1remifentanil preconditioning (RPC2) and 20 μg · kg−1· min−1remifentanil preconditioning (RPC3) groups while not in 2 μg · kg−1· min−1remifentanil preconditioning (RPC1) group than in IR. Magnification: 400×. Scale bar = 100 μm (*P < 0.05 vs . IR).