Nicotinamide mononucleotide (NMN) is a natural
antioxidant approved as a nutritional supplement and
food ingredient, but its protective role in
silicosis characterized by oxidative damage remains unknown. In this study, we generated a
silicosis model by intratracheal instillation of
silica, and then performed histopathological, biochemical, and transcriptomic analysis to evaluate the role of NMN in
silicosis. We found that NMN mitigated lung damage at 7 and 28 days, manifested as a decreasing coefficient of lung weight and histological changes, and alleviated oxidative damage by reducing levels of
reactive oxygen species and increasing
glutathione. Meanwhile, NMN treatment also reduced the recruitment of inflammatory cells and inflammatory infiltration in lung tissue. Transcriptomic analysis showed that NMN treatment mainly regulated immune response and
glutathione metabolism pathways. Additionally, NMN upregulated the expression of
antioxidant genes Gstm1, Gstm2, and Mgst1 by promoting the expression and nuclear translocation of nuclear factor-erythroid 2 related factor 2 (Nrf2). Gene interaction analysis showed that Nrf2 interacted with Gstm1 and Mgst1 through Gtsm2. Promisingly, oxidative damage mediated by these genes occurred mainly in fibroblasts. In summary, NMN alleviates
silica-induced oxidative stress and
lung injury by regulating the endogenous
glutathione metabolism pathways. This study reveals that NMN supplementation might be a promising strategy for mitigating oxidative stress and
inflammation in
silicosis.