Evaluating vaginal moisture in mice with calibrated filter paper.

Objective: Loss of ovarian estrogen (E) production in postmenopausal women causes vaginal dryness and irritation. The contraceptive depot-medroxyprogesterone acetate (DMPA) likewise promotes vaginal dryness by suppressing ovulation and reducing E production. While vaginal dryness in women is identified by self-report, mouse models of estrogen loss require methods are developed to objectively measure vaginal moisture. Methods: Strips of calibrated filter paper, similar to those used to quantify lachrymal secretions, were intravaginally placed in untreated ovary-intact mice, DMPA-treated ovary-intact mice, and ovariectomized (OVX) mice to measure vaginal fluid levels. Results: Median readings from calibrated filter paper strips from DMPA-treated and OVX mice were significantly lower than the median reading from estrus-stage mice. Levels of circulating estradiol were also significantly lower in DMPA-treated and OVX mice vs. estrus-stage mice. Conclusions: Calibrated filter paper provides objective measure of vaginal moisture in mice. Current findings also indicate that hypoestrogenemic mice (DMPA-treated or OVX) accurately model the vaginal moisture losses identified in women with lower levels of circulating E.