Abstract
Background Of all the chemicals released into the environment, nonylphenol (NPL) has been shown to boost oxidative disturbance in the body by interfering in the stability of cells' pro- and antioxidant pathways. A natural substance high in polyphenolic chemicals with antioxidant properties is rutin. This study's objective was to investigate effectiveness of rutin in alleviating oxidative stress and infertility problems induced by NPL in male albino rats.
Methods a total of 40 male rats were separated into 5 groups (8 rats each), aged 6 weeks and 150-170±1.77 gm b.wt and treated orally, 3 times weekly for 60 days. GI: control vehicle (distilled water); GII administrated (50 mg DMSO/kg b. wt.); GIII received (25 mg rutin/kg b. wt.); GIV: intoxicated with (50 mg NPL/kg b. wt.); GV was co-treated with rutin (as in GIII) along with NPL (as in GIV). To measure the quality of the semen, samples were taken for viability, motility, immotile and concentration of sperms assessment. Also, within testicular tissues, superoxide dismutase (SOD), catalase (CAT) activities, and level of malondialdehyde (MDA) were analyzed. Histopathological and immunohistochemical methods were used to examine morphological alterations in the testis. RT-PCR was applied to quantify the expression level of aromatase and steroidogenic acute regulatory (StAR) genes.
Results Oxidative stress is exhibited in NPL-treatment as indicated by decline in sperm quality and activities of CAT, SOD and increasing MDA lipid peroxidation biomarker concentration. Meanwhile, no changes observed in aromatase and steroidogenic acute regulatory (StAR) genes expression. Additionally, histopathological changes and increased tumor necrosis factor –α, and caspase 3 expression level caused by NPL in compared with control group. Rutin improved the deleterious effects of NPL. Rutin alone increased aromatase, decreased StAR genes expression.
Conclusion rutin serves as an effective protective agent against NPL-associated infertility and reproductive failure by modulating steroidogenic, inflammatory, and apoptotic pathways. This research establishes a foundation for using natural polyphenols to counteract the reproductive risks posed by environmental contaminants.

Key words: Aromatase, Biochemical indices, Environmental contaminants, histopathology, Nonylphenol, Rats, Rutin, Spermatozoa, StAR, Testes.