Timing of hormone therapy and its association with cardiovascular risk and metabolic parameters in 4-vinylcyclohexene diepoxide-induced primary ovarian insufficiency mouse model.

Objective: To evaluate the effects of various initiation time points and durations of hormone therapy (HT) on cardiovascular and metabolic parameters of premenarche, primary ovarian insufficiency (POI) mouse model, induced by 4-vinylcyclohexene diepoxide.

Methods: A total of 50 mice at 4 weeks of age were developed into POI mouse model, further randomly categorized into 5 groups: control group without any intervention; no HT group with only high-fat diet (NT); group 1 with delayed estradiol treatment (T1); group 2 with on-time, continuous estradiol treatment (T2); and group 3 with on-time estradiol treatment but early stop (T3). Cardiovascular risk and metabolic parameters were measured.

Results: Presenting with similar body weights, blood glucose levels of T1, T2, and T3 were all significantly lower than NT ( < .001). Serum total cholesterol and insulin were also significantly lower in all HT groups than in NT, especially in T2 ( < .001). For serum low-density lipoprotein-cholesterol, only T2 resulted in the statically lower level than those of NT, T1, and T3 ( < .001). Aortic thickness was significantly increased with aggravated fibrotic change of the intima in NT, and such consequence was significantly ameliorated in HT groups, mostly lowered in T2 ( < .05). Last, serum pro-inflammatory cytokines were significantly low in the HT groups than in NT, especially in T2 with the lowest level ( < .05). .

Conclusions: On-time, continuous E2 treatment immediately after a biologic estrogen deprivation event significantly reduced metabolic and cardiovascular risks in young, pre-menarche female mouse models of POI, confirming decreased serum levels of pro-inflammatory cytokines.