mRNA Rather than Protein Expression of Hepatic Selenoprotein H is More Sensitive to Short-term Low Aflatoxin B₁...

Aflatoxin B₁ (AFB₁) exposure is one of the important factors causing cirrhosis and hepatocellular carcinoma. Selenoproteins, key selenium (Se)-containing biomolecules, may mitigate early AFB₁ hepatotoxicity. To identify hepatic selenoproteins as sensitive biomarkers or functional players in AFB₁ exposure, we allotted 44 11-week-old male C57BL/6J mice into six groups (n = 6-8). Following a five-week pre-feeding period on a 0.03 mg Se/kg diet, mice were fed one of three dietary Se levels (0.03, 0.2, or 2.0 mg/kg) for six weeks, with daily gavage of 0 or 0.25 mg AFB₁/kg body weight administered during the final week. Analysis of the sampled tissues showed that hepatic mRNA abundances of four selenoproteins (Selenoh, Selenok, Selenos, and Sephs2) and 8-oxoguanine DNA glycosylase (Ogg1) were increased across all three dietary Se levels (P < 0.05). In contrast, mRNA abundances of Gpx1, Selenof, Selenoo, Selenot, Selenow, and Txnrd3 were significantly increased at only one or two Se levels (P < 0.05). Notably, Selenoh mRNA abundance positively correlated with dietary Se levels without AFB₁ exposure (R² = 0.22, P = 0.04), while Ogg1 mRNA abundance negatively correlated with serum 8-hydroxydeoxyguanosine concentrations in the AFB₁-treated groups (R² = 0.19, P = 0.04). Selenoh and Sephs2 protein levels were increased by Se intake (P < 0.05), but not by AFB₁ exposure. Conclusively, hepatic Selenoh mRNA was more sensitive to short-term, low AFB₁ exposure than its protein and showed a positive response to dietary Se intake in mice, emphasizing its potential as a valuable biomarker in assessing the Se-AFB₁ interaction.