Fig. 6: Salidroside supplementation enhances fertility in aged females.

a Ovarian morphology with or without Sal treatment at 12 months, exhibiting an increase in the number of growing follicles (arrows) in the Sal group compared to the control (n = 5 mice). b Immunostaining detection of proliferating granulosa cells (red: BrdU, blue: Hoechst) in Sal and vehicle-treated ovaries at 12 months post-PMSG treatment. Statistical analysis revealing a significantly increase in GC proliferating ratio after Sal treatment compared to the control (n = 5 mice). c A significantly higher number of ovulated oocytes was retrieved from Sal-treated ovaries compared to controls after superovulation (n = 8 mice). d Representative images of 2-cells (arrowheads) and blastocysts (arrows) derived from in vitro fertilized oocytes from Sal-treated and control mice. e The ratio of 2-cell embryos (left) and blastocysts (right) significantly increased in Sal-treated mice compared to controls (Control: n = 4 mice, Sal: n = 8 mice). f Fertility test demonstrating a significant increase in litter size (left) after Sal treatment (n = 3 groups, 5 females per group) and general appearance of Sal-treated and control females at 12 months, displaying increased number of healthy pups with Sal-treated mothers (right). g The graphic model illustrates how the decline of ovarian angiogenesis contributes to ovarian aging. In young ovaries, active ovarian angiogenesis results in the development of high-density blood vessels that provide ample nutrition and hormones for follicle growth, thereby ensuring a high fertility efficiency (left). Conversely, reduced angiogenesis in middle-aged ovaries leads to insufficient nutrition and hormone supply, resulting in decreased fertility (middle). Efficiently supplying Sal reverses these age-related negative effects on fertility (right). Data are presented as the means ± SD. Data were analyzed by 2-tailed unpaired Student’s t-test without adjustments; *** P < 0.001, ** P < 0.01, * P < 0.05. Scale bars: 200 μm (a), 100 μm (b, c and d). Source data are provided as a Source Data file including exact P values.