Impacts of high-dose riboflavin on cytotoxicity, antioxidant, growth, reproductive gene expressions, and genotoxicity in the rainbow trout gonadal cells

Riboflavin (vitamin B2 found in food) is a precursor of flavin mononucleotide (FMN) and flavin adenine dinu-

cleotide (FAD), which study as coenzymes for a variety of cellular processes including biosynthesis, homocys-

teine metabolism, detoxification, and various oxidation and reduction reactions. Although studies on the

symptoms resulting from riboflavin deficiency are intense, studies on the effects of high doses of riboflavin are

almost absent. This report aimed to examine the actions of riboflavin on cell viability, the transcriptional ex-

pressions of antioxidant enzyme (gsr and gpx1a), growth (gh1, igf1, and igf2), the reproductive (bol) genes and

DNA damage in the rainbow trout gonad cells (RTG-2) for 48 h. All concentrations of riboflavin (3.125, 6.25,

12.5, 25, 50, and 100 μM) significantly reduced the RTG-2 cell viability. Riboflavin (LD50: 12.5 μM) significantly

downregulated the transcriptional expressions of gpx1a, igf1, and bol genes, while it non-significantly upregu-

lated or downregulated the transcriptional expression of gsr, igf2, and gh1 genes in the RTG-2 cells in comparison

to the control group for 48 h. The comet assay demonstrated that riboflavin significantly raised tail DNA% >10%

DMSO (positive control). Based on the outcomes, high doses of riboflavin exhibit the potential to have a role in

cellular mechanisms, including especially reproduction, DNA damage, and cell death