Melatonin protects against cadmium-induced endoplasmic reticulum stress and ferroptosis through activating Nrf2/HO-1 signaling pathway in mice lung

Cadmium (Cd) is a prevalent heavy metal pollutant known to cause lung damage. However, the mechanisms underlying Cd-induced lung injury and the associated therapeutic strategies remain unclear. By establishing Cd-induced lung damage models both in vivo and in vitro , we observed that Cd inhibited the Nrf2/HO-1 signaling pathway, disrupted the redox balance in lung tissue, accelerated endoplasmic reticulum (ER) stress, and promoted ferroptosis, ultimately leading to lung injury. Melatonin (Mel), a potent reactive oxygen species (ROS) inhibitor with high antioxidative efficacy, mitigated the increasing in ROS and the decreasing in superoxide dismutase levels induced by Cd, as well as the upregulation of PERK-eIF2α-ATF4 signaling associated with ER stress, through the activation of the Nrf2/HO-1 signaling pathway. Furthermore, Mel administration not only prevented Cd-induced iron overload but also reduced lipid peroxidation levels, thereby improving mitochondrial morphological alterations. Collectively, our results demonstrated that Mel treatment alleviated Cd-induced lung injury by inhibiting oxidative stress, which in turn ameliorated ER stress and ferroptosis through the activation of the Nrf2/HO-1 pathway.