Figure 3

Increase in the number of regressing antral follicles in ovaries of MC4R-/- mice. The ovaries of MC4R-/- and MC4R+/+ mice at a mixed C3H/B6 background (1^st cohort) were serially sectioned and either H.E.-stained for counting regressing antral follicles in (A) or PAS-stained for counting zonae pellucidae in (B), the latter at an interval of 168 μm. The final number was calculated for either the whole ovary (A) or for a one millimeter thick ovarian section (B). A: Significantly more regressing antral follicles are counted in MC4R-/- mice compared to MC4R+/+ mice with vaginal signs of estrus and metestrus. B: The range in the number of collapsed zonae pellucidae is strikingly wider in MC4R-/- than in MC4R+/+ mice. Data are depicted as box-and-whisker plots with outliers; n indicates the number of animals; * highlights significant differences (p ≤ 0.05)