Protective roles of gallic acid and lycopene against 4-nonylphenol induced testicular damage in SD rats

4-Nonylphenol (4-NP), an endocrine disruptor, is known to induce mutagenic, toxic, or carcinogenic effects, including testicular toxicity via inducing oxidative stress and apoptosis. The objective of this work was to determine the capacity of lycopene (LC) and gallic acid (GA) to protect testicular histological structure, biochemical responses, and semen parameters in rats exposed to 4-NP. In this 28-day dietary trial, six groups (n= 6 per group) received treatment via oral gavage: a control (corn oil, 2 mL/kg/day), LC (10 mg/kg body weight (BW)/day), GA (50 mg/kg BW/day), 4-NP (125 mg/kg BW/day), LC + 4-NP (LC followed by 4-NP), and GA + 4-NP (GA followed by 4-NP) groups. The results indicated that 4-NP administration adversely affects the final body weight, testicular histology, seminiferous epithelium heights (SEHs) (4-NP: 57.95 ± 0.49, p: 0.000), follicle-stimulating hormone (FSH) level, testis antioxidant capacity, testis malondialdehyde (MDA) level, and sperm viability and morphology. LC and GA supplementation significantly improved SEHs, activities of testis superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), and sperm viability compared to the 4-NP group. Moreover, LC and GA exposures decreased histopathological lesions, including germinal epithelial degeneration, vacuolization, immature germ cells in the tubular lumen, and congestion in the interstitial area. Furthermore, they lowered TUNEL-positive cell counts and tubule percentages, testicular MDA levels, and abnormal sperm percentages. To our knowledge, this study provides one of the first systematic comparisons of lycopene and gallic acid in protecting against 4-NP-induced testicular toxicity under identical experimental conditions. The findings suggest that both compounds preserve testicular structure and function through their antioxidant and anti-apoptotic properties.