Mitochondrial dynamics in prostatic cells during seasonal hyperplasia and atrophy in wild ground squirrels (Spermophilus dauricus).

Seasonal remodeling of reproductive organs is ideal for studying adaptive metabolic regulation under physiological conditions. The wild ground squirrel (Spermophilus dauricus), a typical seasonal breeder, shows pronounced prostate hypertrophy in the breeding season and marked atrophy in the non-breeding season, serving as a natural model for reversible prostate remodeling. Using morphological, histological, immunofluorescence (with MitoTracker staining), immunohistochemical analyses and RT-qPCR, we examined seasonal changes in mitochondrial biogenesis, dynamics, antioxidant capacity, prostate structure and mitochondrial indicators in the squirrel prostate. Results showed seasonal structural differences, characterized by epithelial expansion with putative enhanced secretory activity in the breeding season and stromal predominance in the non-breeding season. Mitochondrial content increased in breeding-season epithelial cells. Consistent epithelial localization of PGC-1α and PGC-1β across seasons, with breeding-season-specific strong epithelial expression of TFAM was observed. Predominance of MFN1/OPA1 (fusion-related) in the breeding season and upregulated DRP1 (fission-related) in the non-breeding season were found. And seasonal differences in the transcription of Tfam, Mfn2, Drp1, Opa1 and Sod2 were identified. In conclusion, mitochondrial biogenesis, fusion-fission balance and antioxidant capacity are seasonally coordinated in the prostate to match tissue demands, providing the first systematic characterization of mitochondrial remodeling in a seasonally breeding mammal's prostate and new insights into adaptive mitochondrial regulation of reversible prostate plasticity.