The sperm hook as a functional adaptation for migration and self-organized behavior.

Area of Science:

• Reproductive Biology
• Sperm Motility and Function

Background:

• Spermatozoa in most murine species possess a characteristic falciform apical hook.
• The precise function of this sperm hook during reproductive processes remains largely unelucidated.

Purpose of the Study:

• To investigate the functional role of the sperm hook in spermatozoa migration through the female reproductive tract in Mus musculus.
• To elucidate the mechanism by which the sperm hook influences sperm-epithelial interactions.

Main Methods:

• Utilized a custom-built two-photon microscope for deep tissue imaging of live reproductive tracts.
• Performed live imaging to observe spermatozoa-epithelium interaction dynamics during migration.

Main Results:

• Evidence suggests the sperm hook facilitates spermatozoa attachment to the uterine and oviductal epithelium.
• Observed synchronized sperm beating, arising from spontaneous unidirectional rearrangement of spermatozoa in the uterus.
• The sperm hook appears to provide mechanical support, aiding anchor-like functions.

Conclusions:

• The sperm hook is crucial for successful spermatozoa migration within the female reproductive tract.
• It enhances spermatozoa-epithelium interactions and provides mechanical support during transit.