Triptolide‐Induced Male Germ Cell Damage Leads to Non‐Infectious Epididymitis in Mice

BACKGROUND: Triptolide is a traditional Chinese medicine used to treat autoimmune and inflammatory diseases. However, one adverse side effect of triptolide is male infertility. While triptolide's testicular toxicity is well-documented, its impact on epididymal function, particularly its role in triggering immune dysregulation (e.g., epididymitis secondary to germ cell damage), remains unclear. OBJECTIVES: The objective is to explore the damage to male germ cells in mice after triptolide administration and analyze how the male germ cells' damage leads to epididymitis. MATERIALS AND METHODS: Triptolide was orally administered to male C57BL/6J mice via gavage, inducing male germ cell damage that subsequently triggered epididymitis. Epididymal epithelial cells (EECs) were challenged with damaged male germ cells (DMGCs) and germ cell components to trigger an immune response. RESULTS: Oral administration of triptolide in mice caused damage to male germ cells. These DMGCs accumulated in the epididymis and triggered epididymitis. The DMGC-triggered epididymitis was characterized by massive immune cell infiltration, primarily macrophages, lymphocytes, along with the upregulation of major inflammatory cytokines, including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), and CXC chemokine ligand10 (CXCL10). Mechanistically, DMGCs and germ cell components, heat shock protein 60 (HSP60) and protamine, activated innate immune responses and induced inflammatory cytokine expression in EECs, which may contribute to epididymitis after triptolide administration. DISCUSSION AND CONCLUSION: Triptolide may induce male germ cell damage, and DMGCs and germ cell components lead to non-infectious epididymitis. The findings provided novel insights into the mechanisms behind triptolide-induced male infertility and can aid in developing preventive and therapeutic strategies to address this side effect. TRIAL REGISTRATION: This study is an animal experimental study and not a clinical trial; therefore, trial registration is not applicable.