Localization of Humanin in Human, Rabbit and Mouse Sperm

Abstract

Humanin (HN) is a peptide showing neuroprotective properties against damage associated with Alzheimer’s disease. In male reproductive system HN is expressed in human and rat testis. This preliminary study aimed to localize HN by immunocytochemistry (ICC) directly in human, mouse and rabbit sperm. Semen samples were processed for the ICC analyses using two different rabbit polyclonal anti-HN antibodies. Western blotting analyses were performed using fresh human semen samples. Normal human, rabbit and mouse sperm, showed HN labeling in sub-acrosomal and mid-piece regions, whereas human abnormally shaped sperm were stained also at acrosomal level and particularly in the flagellum. Western blotting analysis revealed the presence of HN in analyzed human semen samples. HN was localized directly on human, rabbit and mouse spermatozoa. In human samples, we demonstrated a different localization pattern in normally shaped sperm compared to abnormal sperm probably due to a protective effect of HN in pathological sperm