Immersion fixation of rapidly frozen, untreated tissues and suspensions of cells including spermatozoa

Area of Science:

• Cryobiology
• Electron Microscopy
• Tissue Preservation

Background:

• Cryopreservation is crucial for preserving biological samples.
• Traditional methods often require pre-treatment steps.
• Rapid freezing techniques aim to minimize ice crystal formation and damage.

Purpose of the Study:

• To evaluate a rapid freezing method for small tissue pieces and cell suspensions.
• To assess the ultrastructural preservation achieved without pre-treatment.
• To determine the extent of freezing artifacts using transmission electron microscopy (TEM).

Main Methods:

• Small tissue fragments and cell suspensions were stored in artificial insemination (AI) straws.
• Samples underwent rapid freezing in Freon-12 at -155°C without prior cryoprotective agent treatment.
• Peripheral sample portions were thawed directly in 2% glutaraldehyde at 0°C for TEM analysis.

Main Results:

• Satisfactory preservation of cellular ultrastructure was observed.
• Minimal freezing artifacts were detected in the processed samples.
• The direct thawing method in fixative proved effective for TEM evaluation.

Conclusions:

• Rapid freezing in Freon-12 is an effective method for cryopreserving tissues and cell suspensions.
• The absence of pre-treatment simplifies the cryopreservation protocol.
• This technique yields high-quality ultrastructural preservation suitable for TEM analysis.