Impact of the environmental endocrine disruptor 4-octylphenol on reproductive function in pubertal male mice.

4-Octylphenol, a major environmental degradation product of alkylphenols (Aps) used in industry, is an endocrine-disrupting chemical with significant estrogenic activity. It is one of the most toxic Aps, poorly biodegradable in the environment, and can accumulate in organisms through the food chain, thereby affecting the male reproductive system. In this study, the effect of 4-octylphenol on male reproductive health was analyzed. Male pubertal mice were exposed to 4-octylphenol at doses of 0, 1, 10, and 100 mg/kg once daily for 28 days. Our findings indicated that pubertal exposure to 4-octylphenol has significant negative effects on the male reproductive system. Pubertal mice exposed to 4-octylphenol exhibited dose-dependent reproductive toxicity. In the medium- and high-dose groups, a significant reduction in testicular mass, structural damage to the seminiferous tubules, increased oxidative stress and apoptosis within the testicular tissue, and a decline in sperm quality were observed. Additionally, autophagy processes in the testicular tissue, germ cell proliferation, and meiotic processes are inhibited. Serum testosterone and estradiol levels decreased, whereas oxidative stress levels in the testes and spermatozoa increased. In contrast, the low-dose group showed only a reduction in body weight, a decrease in motile sperm count, and mild oxidative stress in the testes without significant pathological changes in Western blot experiments. These results indicate that 4-octylphenol exposure during puberty caused reproductive toxicity in male mice.