`Cadmium induced cardiac inflammation in chicken (Gallus gallus) via modulating cytochrome P450 systems and Nrf2 mediated antioxidant defense

Cadmium (Cd) has been implicated in the pathogenesis of inflammation, myocardial infarction, angiocardiopathy, even cancers. However, it is unknown that Cd-induced cardiac toxicity through Nrf2-mediate antioxidant defense and Cytochrome P450 (CYP450) system. To ascertain the chemoprevention of Cd-induced cardiac toxicity, total 60 newborn chicks were fed with different doses of Cd (0 mg/kg, 35 mg/kg and 70 mg/kg) for a period of 90 days feed administration. Results indicated Cd exposure caused cardiac histopathology changed and functions abnormal, induced NOS activities raised and cardiac inflammation, triggering inflammation factors (IL-6, IL-8, TNF-α, and NF-κb) upregulation and inhabitation of IL-10. Cd caused increase of total CYP450 and Cytochrome b5 (Cyt b5) contents, while erythromycin N-demethylase (ERND), aminopyrin N-demethylase (APND), aniline-4-hydeoxylase (AH) and NADPH-cytochrome c reductase (NCR) indicated opposite situations with different degrees of reduction in microsomes. The mRNA level of most CYP450s isoforms (CYP1A1, CYP1A2, CYP1A5, CYP1B1, CYP2C18, CYP2C45, CYP3A4, CYP3A7 and CYP3A9) were significantly increase but CYP2D6 expression level changed not obvious. Furthermore, Cd treatment caused increased the peroxidation product (MDA) and H2O2 over accumulation, the decreased of T-AOC accompanied by decreased activity of antioxidant enzymes (T-SOD, GST and GPX). Over accumulation of Cd lead to oxidative stress and activated Nrf2 signal pathway through upregulating pivotal target genes (HO-1, NQO1, GCLC, GCLM and SOD). These findings suggested Cd exposure caused cardiotoxicity through CYP450s enzymes homeostasis disturbance and Nrf2-mediated oxidative stress signal pathways defense. These results may provide new evidence on molecular mechanism of Cd-induced cardiac toxicity.