Evaluating vaginal moisture in mice with calibrated filter paper

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.

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.

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.

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.