Anthocyanin-Rich Blackcurrant Pomace Mitigates Oxidative Stress and Affects Steroid Metabolism in the Testes of Rats Exposed to Silver Nanoparticles.

Background/Objectives: Silver nanoparticles (AgNPs), used in industry and medicine, can have a negative impact on the human organism, particularly on the reproductive system, while polyphenolic supplementation may reduce oxidative stress (OS) and enhance male reproductive potential. The aim of this study was to investigate the effects of anthocyanin-rich blackcurrant pomace (BC) on sex steroid hormone metabolism and the OS indicator in the testes of rats following exposure to AgNPs. Methods: Adult rats were fed with a control feed (CTR) or diet supplemented with a 2% BC (BC group). The rats from AgNano and AgNano+BC groups were treated with 20 nm AgNPs (30 mg/kg/day for 28 days by gavage). Results: The plasma testosterone (T) and plasma dihydrotestosterone (DHT) concentrations were decreased in all experimental groups compared to the control (CTR) animals. The co-treatment of animals with AgNPs and BC resulted in decreased oestrogen receptor (ESR2) levels in the testes as compared to rats fed with a diet with BC alone, and the up-regulation of mRNA level of genes involved in T synthesis and metabolism (StAr, Cyp11a1, Hsd17b3, Hsd3b3, Cyp19a1, and Srd5a1), and steroid hormone signalling (AR, ESR1, and ESR2) compared to the Ctr group. The addition of BC to the diet of rats treated with AgNPs resulted in decreased protein carbonyls in the testes as compared to AgNPs-treated animals. Conclusions: The study demonstrated that relatively low AgNPs administration to rats was associated with increased oxidative stress in the gonads. Incorporating BC into the animals' feed mitigated AgNPs-induced oxidative stress and stimulated the expression of genes involved in steroid synthesis and metabolism in testes. The bioactive compounds in blackcurrant pomace have plausible mechanisms to influence reproductive health.