Impacts of simultaneous exposure to arsenic (III) and copper (II) on inflammatory response, immune homeostasis, and heat shock response in chicken thymus

Arsenic and copper, two common environmental contaminants, presented potentially harmful to the immune system. In order to examine whether simultaneous exposure to arsenic and copper has the potential effects on immunity and inflammatory response in chicken thymus, 30 mg/kg arsenic trioxide and/or 300 mg/kg copper sulfate were added to chicken basal diet, respectively. After 12 weeks of administrations, we observed significantly decreased thymus weight and thymus index, inflammatory cell infiltration and hyperemia visible to the unaided eye. Concurrent administration arsenic and copper markedly increased levels of NF-κB, COX-2, iNOS and PTGEs and pro-inflammatory cytokines in concomitant with a tendency of Th1 bias immune response. Additionally, heat shock proteins levels were noticeably elevated in all treated groups. Above mentioned indicators were more pronounced among co-administrated groups. Collectively, arsenic and/or copper exposure engendered immunotoxicity of chicken thymus, resulting in inflammatory responses and imbalance of the immune response. Concurrent exposure of arsenic and copper was likely to potentiate the toxicity of chicken thymus and detailed mechanisms required further exploration. Heat shock proteins may play protective roles in thymus damage, and HSP60 combines with the IL-17/IL-10 ratio may be potential predictive marker of arsenic and/or copper-subchronic toxicity in chicken thymus.