Human cervical mucus can act in vitro as a selective barrier against spermatozoa carrying fragmented DNA and chromatin structural abnormalities

Purpose: We have carried out experiments to determine if human cervical mucus can act as an in vitro selective barrier against spermatozoa morphologically normal that carry genetic structural abnormalities. Methods: Sperm chromatin abnormalities have been evaluated by Chromomycin A(3) and endogenous nick translation. Results: The data obtained have shown that spermatozoa possessing higher levels of DNA protamination are more proficient in crossing the cervical mucus barrier. Moreover, the levels of positivity to endogenous nick translation treatment was practically zero in such spermatozoa. Conclusions: We suggest that sperm penetration of cervical mucus could be used to select sperm preparations free of fragmented DNA or chromatin structural abnormalities for assisted reproduction.