Iron oxide nanoparticles reversibly affect sperm quality in Wistar rats

Iron oxide nanoparticles (IONP) are being utilised for various biomedical applications due to their unique properties like superparamagnetism and greater colloidal stability. Interaction of IONP with male reproductive system is underrepresented in the literature. Current study strives to demonstrate the effects of IONP on sperm quality, reproductive hormones and fertility of adult Wistar rats. Spherical IONP with 15-20 nm size were injected for a maximum of 60 days in three different exposure schemes. Three increasing doses (20, 40 and 80 mg/kg) along with a control group were tested. Sperm count, sperm viability, motility and morphology were scored after the experimental periods. A group of rats was used to examine male fertility. Concentrations of male reproductive hormones in serum were also measured in all groups. Total sperm count and motility was significantly decreased in treated groups in comparison to control after 60 days of exposure. Changes in sperm viability and sperm morphology mostly proved to be statistically insignificant. Serum concentrations reproductive hormones like testosterone, luteinizing hormone and follicular stimulating hormone varied insignificantly between control and treatment groups. Male fertility was also not affected due to the exposure. Further, it is also reported that a 45-day recovery period restores the sperm quality up to a considerable extent. Overall, the study demonstrates that long term exposure of IONP has adverse effects on male sperm production and function that can be reversed if exposure is withdrawn.