Centrifugation on Percoll gradient enhances fluorescent lectin binding on human sperm: a flow cytometric analysis

Area of Science:

• Reproductive Biology
• Cell Biology
• Biochemistry

Background:

• Percoll gradient centrifugation is standard for isolating motile sperm for assisted reproduction.
• This method may also induce sperm capacitation, a necessary step for fertilization.
• Changes in sperm surface glycosylation are implicated in capacitation and fertilization.

Purpose of the Study:

• To investigate whether Percoll centrifugation alters sperm surface glycosylation patterns.
• To determine if these alterations are linked to sperm capacitation and fertilization readiness.

Main Methods:

• Compared lectin binding to sperm membranes before and after Percoll centrifugation using flow cytometry.
• Utilized 15 different fluorescein-conjugated lectins to probe glycosylation.
• Analyzed 60 sperm samples.

Main Results:

• Significant increases in lectin-labeled sperm counts and mean fluorescence intensity were observed for most lectins tested after Percoll centrifugation.
• Microscopic analysis confirmed increased lectin binding on the sperm acrosome and equatorial plates post-centrifugation.
• These findings support the hypothesis of altered glycosylation.

Conclusions:

• Percoll centrifugation significantly modifies sperm surface glycosylation patterns.
• These modifications, particularly on the acrosome and equatorial plates, are likely associated with induced sperm capacitation.
• The observed changes suggest Percoll centrifugation enhances sperm functionalization for fertilization.