Changes of N6-methyladenosine and ferroptosis in cadmium-induced reproductive toxicity of male mice fed a high fat and high sugar diet

Cadmium (Cd) and high-fat and high-sugar diet (HFHS) are risk factors contributing to the decline in male sperm quality. N⁶-methyladenosine (m⁶A) is essential in the processes of testicular development and spermatogenesis. Ferroptosis, a form of cell death that depends on iron, is prone to causing testicular dysfunction. However, the changes in m⁶A modification regulatory proteins and ferroptosis signaling molecules in male mice with sperm abnormalities resulting from combined exposure to Cd and HFHS remain incompletely elucidate. Our present data indicate that the combined treatment of Cd and HFHS significantly reduced sperm quality in comparison to those in single Cd or HFHS treatment. In addition, indicators related to ferroptosis in the combined treatment of Cd and HFHS group have also undergone significant changes. In detail, the contents of malondialdehyde (MDA) and Fe²⁺ as well as Slc7a11 expression were increased while Gclc expressions were reduced in the testicular tissue of Cd and HFHS combined treatment mice. Further detect results showed that the combined exposure to Cd and HFHS synergistically elevated the m⁶A modification levels alongside a downregulation of the Mettl3, Fto, Alkbh5 and Ythdc2 at the protein level when compared with those in single Cd or HFHS treatment. Altogether, it can be inferred that Cd and HFHS combined treatment may alter the levels of m⁶A modification regulatory proteins in testicular tissue, leading to increased Fe²⁺ and MDA production, thus activating the Slc7a11/Gpx4 signaling pathway, ultimately decreasing the sperm quality in mice, providing preliminary evidence for the occurrence of ferroptosis in testicular cells. Our findings may provide direction for the study of reproductive toxicity of cadmium and offer reference for the selection of molecular targets.