Immunohistochemical Demonstration of Nitrosative Tissue Damage in Copper Induced Liver Toxicity in Japanese Quails

Abstract

Summary Excess copper may cause liver toxicosis in various species. In this study, nitrosative tissue damage was investigated in an experimental chronic copper toxicity model in Japanese quails by immuno-histopathological means. Four groups (control, 1 st , 2 nd and 3 rd ), each comprised of 10 one-day-old chicks, were fed for 6 weeks with rations containing none, 100, 250 and 500 ppm copper sulfate, respectively. At the end of the feeding period, animals were euthanized, liver tissues were collected and processed routinely for histopathologic applications. Immunohistochemical staining was performed for inducible nitric oxide synthase (iNOS) and nitrotyrosine antibodies with indirect avidin-biotin peroxidase technique. Apoptotic cell death was investigated with in situ TUNEL staining. Microscopically, there were only mild and moderate degenerative changes in the liver of the chicks of 2 nd and 3 rd groups, respectively. In immunohistochemical staining, little immunoreactivity was detected in the control group for both antibodies. Immunoreactivities were gradually stronger with the increasing copper concentration. A few apoptotic hepatocytes were present only in the 3 rd group. These findings suggest that nitric oxide play a role in the oxidative