Fig. 4

Repeated SD does not affect estrus cycling. Vaginal smears were collected daily for 2 weeks while mice underwent repeated opto-SD × 7 SDs (n = 5) and compared to sham mice (n = 5, A). Cycles from individual mice are shown in (B) for opto-SD and sham animals. The time in days between consecutive diestrus, estrus metestrus or proestrus stages were averaged in sham and opto-SD groups to estimate the duration of the estrus cycle. There was no effect of repeat opto-SD on duration of the cycle as measured by interval days between consecutive cycle stages in opto-SD versus sham animals (cycle stage used: F = 2.02, p = 0.131; SD: F = 0.44, p = 0.514, C). More time was spent in estrus followed by proestrus, diestrus and metestrus cycle stages for both groups, (D). When data were grouped in PE and MD stages, there was no difference in the total number of days spent in PE or MD stages between sham and opto-SD groups over the 2 weeks tested (F = 0, p > 0.9999, two-way ANOVA, E)