Fig. 7: Oral administration of BHB partially alleviates testicular aging in aged mice.

a Schematic of oral administration of BHB and subsequent analysis. b Water and food consumption between salt and BHB-treated mice. n = 10 per group. c The concentration of BHB in serum and testes. n = 5 per group. d Left: the representative western blots for H3K9ac and Histone H3 in testes of different mice. Right: quantitative analysis of the H3K9ac protein level, relative to Histone H3. n = 3 per group. e Representative western blots for FOXO3a and GAPDH in testes of different mice. Right: quantitative analysis of the FOXO3a protein level, relative to GAPDH. n = 3 per group. f Left: representative images of testicular sections from indicated groups. The sections were stained with LCs marker CYP17A1, and SA-β-gal. Scale bar: 75 μm. Right: quantitative analysis of the CYP17A1⁺ SA-β-gal⁺ cells. n = 3 per group. g Left: representative confocal images of testicular sections from indicated groups. The sections were stained with senescence marker p21, HSD3β, and DAPI. Scale bar: 50 μm. Right: quantitative analysis of the p21⁺ HSD3β⁺ cells. n = 3 per group. h, i Quantitative RT-PCR analysis of senescence markers (p21, Cxcl10). n = 3 per group. j–m Serum testosterone (j), intratesticular testosterone (k), serum Insl3 (l), serum LH (m) level of the indicated groups. n = 20 per group in (j), n = 5 per group in (k), n = 12 per group in (l), n = 12 per group in (m). n–q Representative light micrographs of sperm acquired from indicated groups (n). Scale bar: 100 μm. Sperm concentration (o), proportion of sperm with motility (p), proportion of sperm with progressive motility (q). n = 10 per group. Data were presented as mean ± SEM. Significance was determined by one-way ANOVA (b-water consumed, c–h, k, o–q) or Kruskal-Wallis test (b-food consumed, i, j, l, m). Illustrations were created with BioRender. Source data are provided as a Source Data file.