EN
The aim of the study was an immunhistochemical evaluation of the expression of Apaf 1, Apaf 2 and Apaf 3 (apoptotic protease activating factors) in L-arginine, a substrate of nitric oxide (NO) inducing apoptosis of rats’ hepatocytes. The rats used in this experiment were divided into 2 equal groups. Experimental rats received per os L-arginine 40 mg/kg body weight every other day for 2 weeks and were decapitated after 3 weeks of the experiment. Control rats received per os 2 ml of distilled water every other day for 2 weeks and were decapitated after 3 weeks of the experiment. Specimens of the liver taken after decapitation were examined immunohistochemically, using the standard three-step method to detect the immunolocalization of Apaf 1, Apaf 2, Apaf 3. The results of immunohistochemical examinations were subjected to qualitative evaluation based on the intensity of a colour reaction at the antigen-antibody site in the rat liver examined in individual groups. The quantitative evaluation was conducted with the Analysis-pro software. The surface area of cells with a positive colour reaction (+) of antigen-antibody was calculated. The results of the study show that L-arginine, as a donor of exogenous nitric oxide, did not have an apoptotic effect leading by the intrinsic pathway, through the formation of the apoptosome and the activation of caspase 9 in the hepatocytes of rats.