Methodological contributors to estrous-cycle variability in DHEA-induced mouse models of polyendocrine metabolic...

Dehydroepiandrosterone (DHEA)-induced rodent models are widely used in polyendocrine metabolic ovarian syndrome (PMOS; formerly polycystic ovary syndrome [PCOS]) research, yet their reproducibility is limited by substantial methodological variability. While rats are often reported to exhibit diestrus arrest, mouse studies describe estrus-dominant or mixed-stage arrest, differences frequently attributed to species effects; however, heterogeneity in experimental design may also contribute. We synthesized 25 published DHEA-induced rodent studies and characterized estrous-cycle dynamics in a C57BL/6 model using one commonly used DHEA protocol. Key methodological variables-including induction age, DHEA brand and solvent, dosage, administration duration, smear-sampling timing, and cytological criteria-were extracted and examined using a semi-quantitative comparative approach. Estrous-arrest patterns were compared across methodological subgroups to formulate provisional, evidence-informed recommendations. Substantial variability in estrous-arrest patterns was identified across studies, although subgroup differences were not statistically significant. Approximately 60% of C57BL/6 studies reported estrus-dominant arrest when DHEA was administered at 6 mg/100 g body weight, sesame oil was used as the solvent, and induction began before postnatal day 28. Our experiment confirmed that the selected protocol can produce estrus-dominant arrest, but it did not compare alternative doses, solvents, induction ages, or sampling schedules. Directional trends suggested that DHEA dosage, solvent type, and induction age may contribute to estrous outcomes. Overall, methodological factors may contribute substantially to estrous-cycle variability in DHEA-induced mouse models; however, the available evidence does not establish them as dominant or causal determinants. These findings identify candidate methodological contributors and support provisional recommendations to improve reporting and cross-study comparability, while direct comparative experiments integrating endocrine and ovarian endpoints remain necessary for validation.