Human papillomavirus detected in sperm of Japanese infertile males affects reproductive parameters

The effects of human papillomavirus (HPV) infection on male reproductive parameters are currently a matter of controversy. In order to clarify the issue in Japanese infertile men, the prevalence and localization of HPV in semen, sperm parameters, and superoxide dismutase (SOD) activity in seminal plasma were examined in 216 Japanese infertile men.

DNA was extracted from liquid-based cytological semen samples. The β-globin gene was amplified by polymerase chain reaction (PCR), and HPV-DNA was amplified using nested PCR with MY09/MY11 as outer primers and GP5+/GP6+ as inner primers. HPV genotyping was performed in the HPV-positive samples. In addition, SOD levels in seminal plasma were analysed quantitatively. In-situ hybridization (ISH) was performed to localize HPV-DNA in sperm from HPV-positive samples.

Any-risk and high-risk prevalence rates of HPV in semen were 12.5% and 6.9%, respectively. No significant difference in the prevalence of HPV was observed between azoospermic and non-azoospermic subjects. Among non-azoospermic patients, those with HPV detected in semen had significantly lower sperm motility and concentration compared with subjects without HPV detected in semen. SOD levels in seminal plasma were significantly higher in HPV-positive patients compared with HPV-negative patients. ISH analysis of HPV-positive samples revealed that HPV-DNA was localized to the head and mid-piece of sperm. HPV-DNA was present in the sperm of young infertile men.

HPV infection of sperm was associated with reduced sperm motility and concentration, and resulted in an increase in seminal SOD activity.