الفهرس 
CHAPTER I: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The prevalence of male infertility has been increased so widely in modern life. There is a great body of evidence blaming nanomaterials for their toxic effects on the male reproductive capacity. Silver nanoparticles (AgNPs), being antimicrobial agent are widely utilized in many consumer products that rings an alert to assess their toxicological potential on the male reproductive system. In contrast, antioxidants intake is associated with reducing the risks of many diseases. Lycopene (LYC), as a powerful antioxidant was previously reported to alleviate testicular damage caused by different environmental toxicants. Therefore, this study was conducted to evaluate the toxic effects of AgNPs on the reproductive capacity of male albino rat as a mammalian model and the possible attenuating role of lycopene. Twenty eight male rats were categorized into four groups (7 per each); control group received distilled water, lycopene group received 5 mg/kg b.wt. LYC, nano-silver group received 100 mg/kg b.wt. AgNPs and the last group received both AgNPs and LYC at their same dosages. All doses were administrated by oral gavage daily for 60 days. The results revealed that AgNPs exposure decreased the normal gain in the body weight and decreased the testicular and epididymal weights. Declined sperm count and morphologically abnormal sperms were detected. Analysis of testicular homogenate revealed a high level of alkaline phosphatase (ALP) and a low level of succinate dehydrogenase (SDH). Levels of testicular antioxidants, superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) were also shown to be decreased while lipid peroxidation marker (MDA) level was increased. Testicular sections of AgNPs group showed a degenerative appearance and morphometric changes of the seminiferous tubules (STs). Immuno-staining for testicular caspase-3 and tumor necrosis factor alpha (TNF-α) detection revealed a strong expression in testicular sections of AgNPs group. On contrast, LYC co-treatment was found to maintain the normal gain in the body weight and attenuate the reduction of testicular and epididymal weights. Sperm count and morphology were shown to be normalized. Testicular enzymes and oxidative status markers were restored to nearly normal levels. Lycopene also ameliorated the histological and morphometric changes of the STs and attenuated apoptosis and inflammation evidenced by the low expression of caspase-3 and TNF-α in testicular sections of LYC co-treated group. It can be concluded that AgNPs have adverse effects on male reproductive capacity and LYC can effectively ameliorate their inducible damage. Therefore, regulations should be set on AgNPs industrial usage and antioxidants daily intake such as LYC is highly recommended.