Assessment of arsenic trioxide toxicity on cock muscular tissue: alterations of oxidative damage parameters, inflammatory cytokines and heat shock proteins.

To evaluate the toxicity of arsenic trioxide (As2O3) in the muscular tissues (wing, thigh and pectoral) of birds, 72 one-day-old Hy-line cocks were selected and randomly divided into four groups. They were fed either a commercial diet or an arsenic-supplemented diet containing 7.5, 15 or 30 mg/kg As2O3. The experiment lasted for 90 days and the samples of muscular tissues were collected at 30, 60 and 90 days. The results showed that As2O3 exposure significantly lowered the activities of antioxidant enzymes (catalase (CAT), glutathione peroxidase (GSH-Px)) and inhibition ability of hydroxyl radicals (OH) and increased the malondialdehyde (MDA) contents. Furthermore, the mRNA levels of inflammatory cytokines (tumor necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS), prostaglandin E synthase (PTGEs)) and heat shock proteins (HSPs) in muscular tissue were significantly upregulated in the As2O3 exposure groups. The results indicated that As2O3 exposure resulted in oxidative damage, induced the inflammatory response, and influenced the mRNA levels of HSPs in muscular tissue of cocks. Additionally, the results suggested that HSPs possibly resisted due to the As2O3 exposure-induced oxidative stress and inflammatory response, which provided a favorable environment and played protective roles in the muscular tissues of cocks. The information presented in this study is helpful to understand the mechanism of As2O3 toxicity in bird muscular tissues.