Metabolomics and exploratory mendelian randomization identify indole-3-propionic acid associated with doxorubicin-induced testicular injury.

Doxorubicin (DOX) exhibits severe side effects that restrict its clinical application. In the testes, DOX triggers apoptosis and excessive oxidative stress. Modulation of the metabolic microenvironment may contribute to the amelioration of testicular injury. However, the relationship between DOX and alterations in testicular metabolites remains elusive. In this study, the metabolic profiles of the testes and plasma were analyzed in mice with DOX-induced testicular injury. Mendelian randomization (MR) analysis was employed to prioritize candidate metabolites associated with the risk of male infertility in human cohorts. Furthermore, the roles of prioritized metabolites were validated in cells. A total of 76 metabolites in the testes and 48 metabolites in the plasma exhibited alterations, with 24 metabolites showing changes in both tissues. Although statistical significance was not maintained following FDR correction, the exploratory MR analysis prioritized indole-3-propionic acid (IPA) for its potential inverse association with male infertility. In TM4 cells, IPA attenuated DOX-induced reactive oxygen species accumulation and regulated the protein expression of the NRF2/HO-1 pathway. Collectively, these findings characterize the metabolic disturbances underlying DOX-induced testicular injury and highlight IPA as a candidate metabolite for further investigation.