Subchronic acrylamide treatment induces superoxide dismutase 1 expression in rat liver

Abstract

INTRODUCTION: Acrylamide (AA) is a widely used chemical and an important monomer in various industrial and laboratory purposes. In addition, AA is formed in many types of fried and oven-baked foods during cooking. Considering proven neurotoxic, carcinogenic and mutagenic effects on living organisms, AA became a main topic of interest for many research groups. OBJECTIVES: The objective of our study was to determine whether acrylamide treatment affects superoxide dismutase 1 (SOD1) expression in rat liver. METHOD / DESIGN: Adult male Wistar rats were subchronicly (three weeks) treated with 25 mg/kg or 50 mg/kg body weight (b.w.) of AA. Formalin-fixed paraffin-embedded liver tissue was cut into 5 µm thin sections and immunostained with anti-SOD1 antibody. The amount of SOD1 in immunostained sections was determined using Windows based ImageJ program (ImageJ, Version 1.50f). The optical density (OD) and stained percentage color area of immunolabeled SOD1 were measured. RESULTS: Figure 1. Representative micrographs of superoxide dismutase 1 (SOD1) immunohistochemical staining in liver of control rats, rats treated with acrylamide (AA) in dose of 25 mg/kg b.w., and rats treated with acrylamide in dose of 50 mg/kg b.w. (a). Optical density of SOD1 immunopositive cells in control and AA-treated rats in doses of 25 mg/kg b.w. and 50 mg/kg b.w. (b). Percentage contribution of high positive, positive, low positive and total positive immunohistochemical staining of SOD1 in control and AA-treated rats in doses of 25 mg/kg b.w. and 50 mg/kg b.w. (c). Values in charts are means ± SEM; n = 10, *p < 0.05. In statistical analysis AA-treated animals were compared with the control group. CONCLUSIONS: Immunostaining of SOD1 in liver of control rats showed weak cytoplasmic immunoreactivity in hepatocytes (Fig. 1a). AA application induced dose dependent increase of immunostaining intensity (Fig. 1a). Significant increase of OD and percentage contribution of low positive and total positive cells of immunostained SOD1 was detected in group treated with AA in a dose of 50 mg/kg (Fig.1b, c).