Micro-straw: An efficient cryopreservation carrier for rare human spermatozoa

Area of Science:

• Reproductive Biology
• Cryopreservation Technology
• Spermatozoa Preservation

Background:

• Various cryopreservation carriers exist for freezing rare human spermatozoa.
• Comparative effectiveness and attributes of these carriers remain understudied.

Purpose of the Study:

• To compare the effectiveness of the Micro-straw carrier against Cryoplus and LSL straw carriers for cryopreserving rare human spermatozoa.
• To determine the optimal freeze-thaw protocol for the Micro-straw carrier.

Main Methods:

• Sperm samples from healthy donors (n=93) and patients with various infertility diagnoses (n=40) were used.
• Optimal freeze-thaw protocol for Micro-straw was established.
• Post-thaw survival, morphology, acrosome integrity, and DNA fragmentation were assessed for Micro-straw, Cryoplus, and LSL carriers.

Main Results:

• Micro-straw achieved optimal motility with specific freezing (70s above LN2) and thawing (40s at 42°C) protocols.
• No significant differences in progressive motility, acrosome integrity, or DNA fragmentation were found among carriers.
• Micro-straw showed significantly higher normal morphology rates than Cryoplus and higher total motility rates than LSL.

Conclusions:

• Micro-straw, Cryoplus, and LSL carriers are all effective for freezing rare human spermatozoa.
• The Micro-straw carrier is recommended due to its superior cost-effectiveness, safety, and ease of use.