Erzhi pills: a potential aging-modulating agent targeting immunosenescence in mice.

Erzhi Pills (EZP), a traditional Chinese herbal formula, has demonstrated potential aging-modulating properties, while its mechanisms in modulating immunosenescence remain incompletely understood. Two complementary aging murine models were employed to investigate the anti-immunosenescence efficacy of EZP, providing experimental validation for its translational application in delaying age-related immune decline. Morphological and physiological parameters were monitored and thymic/splenic organ coefficients were calculated. Histopathological evaluation of thymic involution was performed via hematoxylin-eosin (H&E) staining. Flow cytometry quantified splenic T cell subsets (naïve/memory CD4+ and CD8+ T cells). Reverse transcription quantitative PCR (RT-qPCR) analyzed mRNA expression of key immunosenescence markers (Lin28a, GDF-11, Sirt1, IL-2, IL-17), while enzyme-linked immunosorbent assay (ELISA) measured serum levels of pro-inflammatory cytokines (TNF-α, IFN-γ). Metabolomic profiling further elucidated EZP's bioactive pathways. EZP administration significantly attenuated age-related degeneration in both murine models by restoring thymic and splenic architecture, as evidenced by increased organ coefficients and reduced histopathological damage. EZP rebalanced T cell homeostasis through selective expansion of naïve T cells and contraction of memory T cell subsets, with a pronounced increase in CD8+ T cell populations. At the molecular level, EZP upregulated Lin28a, Sirt1, and IL-2 expression while modulating systemic cytokine profiles-reducing TNF-α and augmenting IFN-γ in the natural aging cohort. These findings suggest EZP mitigates chronic inflammatory aging and enhances immune responsiveness of effector T cells. EZP's anti-aging mechanism was mediated by fatty acid metabolism modulation. This study provides evidence supporting EZP's potential as a novel therapeutic strategy for immunosenescence and warrants further investigation into its clinical translation for geriatric populations.