Fig. 3.  Effects of nitric oxide donor and nitric oxide synthase inhibitor on hepatic histology and apoptosis (n = 10 in each group). (A  and B ) Photograph depicts typical pattern of focal necrosis after ischemic insult. Black arrows indicate ischemic changes that were seen more seriously in N -ω-nitro-l-arginine methyl ester (L-NAME) treatment and ischemia-reperfusion (IR) groups compared with other groups. Magnification: 200×. Scale bar = 200 μm (*P < 0.05 vs . IR). (A  and C ) The degree of apoptosis and the number of terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) positive cells (black arrows) were decreased in 2 μg · kg⁻¹· min⁻¹remifentanil preconditioning (RPC) and l-arginine (L-arg) pretreated groups. Magnification: 400×. Scale bar = 100 μm (*P < 0.05 vs . IR). H&E = hematoxylin and eosin.