Objective: Cyclophosphamide (CP), a chemotherapeutic agent, has been shown to inhibit spermatogenesis. Accordingly, the primary objective of this study was to evaluate the potential therapeutic benefits of quercetin‑loaded nanoselenium (quercetin‑loaded selenium nanoparticles [SeNPs]) in mice treated with CP. Methods: Thirty‑five adult male mice were randomly assigned to five groups (n=7 per group): control, quercetin‑loaded SeNPs (20 mg/kg, daily for 5 weeks), CP (200 mg/kg, single dose), treatment A (CP+quercetin‑loaded SeNPs), and treatment B (CP+quercetin, 20 mg/kg daily for 5 weeks). Sperm parameters, DNA fragmentation index, catalase activity, levels of glutathione (GSH), glutathione disulfide (GSSG), malondialdehyde (MDA), and reactive oxygen species (ROS) were evaluated in all groups, along with histological assessments of testicular tissue. Results: In CP‑treated mice, administration of quercetin‑loaded SeNPs (treatment A) significantly improved sperm parameters, including total count, motility, morphology, and DNA integrity. Treatment also markedly increased the numbers of spermatogonia, primary spermatocytes, spermatids, Sertoli cells, and Leydig cells in testicular tissue. Furthermore, treatment with quercetin‑loaded SeNPs resulted in a significant increase in catalase activity and GSH levels while significantly reducing GSSG, MDA, and ROS levels in CP‑induced testicular damage. Conclusion These findings suggest that quercetin‑loaded SeNPs enhance spermatogenesis in a CP‑induced mouse model by improving the antioxidant profile and testicular stereological parameters.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus found in China in 2019. The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), has been found to be closely related to the cells that secrete angiotensin-converting enzyme 2 (ACE2). ACE2 is involved in the renin-angiotensin system and is widely secreted in several tissues, including the testis, which has raised concerns because organs with high expression of the ACE2 receptor are susceptible to infection. Analyses have shown that in testicular cells, such as spermatogonia, seminiferous duct cells, Sertoli cells, and Leydig cells, there is a high expression level of ACE2. Therefore, SARS-CoV-2 may damage male reproductive tissues and cause infertility. Since male infertility is an important problem, scientists are evaluating whether COVID-19 may influence male infertility through the ACE2 receptor.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus found in China in 2019. The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), has been found to be closely related to the cells that secrete angiotensin-converting enzyme 2 (ACE2). ACE2 is involved in the renin-angiotensin system and is widely secreted in several tissues, including the testis, which has raised concerns because organs with high expression of the ACE2 receptor are susceptible to infection. Analyses have shown that in testicular cells, such as spermatogonia, seminiferous duct cells, Sertoli cells, and Leydig cells, there is a high expression level of ACE2. Therefore, SARS-CoV-2 may damage male reproductive tissues and cause infertility. Since male infertility is an important problem, scientists are evaluating whether COVID-19 may influence male infertility through the ACE2 receptor.