The effect of patulin on oxidative stress and global DNA methylation in C57BL/6 mice hearts.

Abstract

Mycotoxins are chemical compounds produced by fungi that, when ingested, induce a variety of diseases including hepatotoxicity, nephrotoxicity, gastrointestinal toxicity, neurotoxicity, and immunotoxicity. Patulin (PAT) is a common mycotoxin produced by Penicillium, Aspergillus, and Byssochlamys fungal species, and is commonly found in apples and its products. Researchers have reported that consumption of PAT-contaminated foods causes nephrotoxicity and hepatotoxicity; however, its effects on the heart are unknown. Following reports that PAT causes oxidative stress and epigenetic changes, this study assessed if PAT induces oxidative stress and global DNA methylation in C57BL/6 mice hearts. Methods included: (i) ten mice treatment with PAT (2,5mg/kg) and PBS (0,1M) for 24hr, five mice per treatment group, (ii) thiobarbturic acid reactive substances (TBARS) assay (lipid peroxidation), (iii) quantitative polymerase chain reaction (gene expression of kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase (GPx), superoxide dismutase 2 (SOD2), catalase (CAT), methyl-CpG binding domain protein 2 (MBD2), DNA methyltransferases (DNMT1, DNMT3A, DNMT3B), (iv) western blot (protein expression of Nrf2, SOD2, CAT, MBD2, DNMT3A and DNMT1), (v) enzyme-linked immunosorbent assay (global DNA methylation levels). PAT caused an induction of oxidative stress as indicated by the significant increase in malondialdehyde (MDA) levels (0.52-fold, p = 0.005). PAT significantly increased gene expression of Nrf2 (1.20-fold, p=0.049), GPx (1.20-fold, p = 0.028), SOD2 (1.40-fold, p = 0.042) and CAT (0.90-fold, p = 0.038); and significantly decreased gene expression of keap1 (1.10-fold, p = 0.007). PAT increased expression of Nrf2 protein, significantly (0.64-fold, p = 0.005), SOD2 (2.40-fold, p = 0.020), and CAT (1.88-fold, p = 0.004). Additionally, PAT suppressed the gene expression of DNMT3A (0.41-fold, p = 0,0001) and MBD2 (0.45-fold, p = 0,0001) and increased the gene expression of DNMT1 (1.48-fold, p = 0,02) and DNMT3B (1.62-fold, p = 0,04). PAT increased the protein expression of DNMT1 (0.68-fold, p=0.029); and significantly decreased the protein expression of MBD2 (0.48-fold, p=0.008) and DNMT3A (0.50-fold, p = 0.0001). The alterations in DNMTs and MBD2 led to PAT-induced global DNA hypermethylation (1.72-fold, p = 0,02). In conclusion, PAT induced oxidative stress and global DNA hypermethylation in C57BL/6 mice hearts and is toxic to the heart.