Effects of Intermittent fasting protocols on sperm parameters and testicular ultrastructure in rats fed a high-fructose diet

This study aimed to evaluate two intermittent fasting (IF) protocols (8:16 and 5:2) on sperm parameters and testicular microarchitecture in rats fed a high-fructose (HF) diet. Forty 12-week-old male Wistar albino rats were divided into four groups: Control, HF(20% fructose), (8:16)+HF (16-h daily fast), and (5:2)+HF(two fasting days/week). Following the 8-week treatment, biochemical, histological, and ultrastructural (TEM) analyses were performed.HF-diet led to significant weight gain and hyperglycemia. Both IF protocols effectively reduced body weight, while 8:16 IF significantly lowered glucose levels (p < .05). The control group showed significantly higher sperm counts and motility compared to the HF and 5:2 IF groups (p < .001). The 5:2 IF group showed the most severe degeneration, with significantly reduced Johnsen scores compared to both control and HF groups(p = .001).Histopathologically, the HF group exhibited deformed seminiferous tubules and basement membrane disorganization. Ultrastructural findings confirmed mitochondrial cristae loss, cytoplasmic vacuolization, and increased apoptosis in both IF groups, with the 5:2 protocol showing more pronounced heterochromatic nuclei and lipid droplet accumulation. While IF – particularly the 8:16 – effectively manages metabolic parameters like weight and glucose under HF diet conditions, it may exacerbate testicular damage and impair spermatogenesis. Specifically, the 5:2 IF protocol appears to have a more detrimental effect on sperm quality and testicular ultrastructure.