Decapitated and decaudated spermatozoa in man, and pathogenesis based on the ultrastructure

Area of Science:

• Reproductive Biology
• Spermatozoa Ultrastructure
• Male Infertility

Background:

• Investigating the ultrastructure of spermatozoa from infertile men.
• Examining decapitated sperm heads and decaudated tails to understand structural defects.
• Analyzing developing spermatids for abnormalities in centriole placement and flagellum formation.

Observation:

• Decaudated sperm heads lacked implantation fossa and basal plate at the nuclear pole.
• Decapitated sperm tails retained normal ultrastructure, including axoneme and sheaths, suggesting motility.
• Developing spermatids exhibited abnormal centriole behavior, with distal centrioles forming flagella independently.

Findings:

• Absence of the implantation fossa and basal plate in decaudated sperm heads.
• Presence of intact tail structures in decapitated tails, indicating potential for motility.
• Disrupted centriole anchoring to the nucleus in developing spermatids.

Implications:

• Tail separation from the head may occur during spermatid development, before or after tail formation.
• The failure of the proximal centriole to connect with the nucleus is a key abnormality.
• These defects likely contribute to male infertility by impairing sperm structure and function.