How should mice be properly thawed? - briefly
Place the animals in a pre‑warmed (≈37 °C) water bath, gently agitate until all tissue is liquid, then transfer immediately to the designated cage. Verify complete thawing by visual inspection and maintain sterile conditions throughout.
How should mice be properly thawed? - in detail
Mice recovered from cryopreservation require a controlled thawing protocol to maintain viability and reduce stress. The recommended procedure includes the following steps:
- Transfer frozen containers from liquid nitrogen storage to a 4 °C refrigerator. Keep the vials sealed to prevent condensation.
- Allow the temperature to rise gradually for 30–45 minutes, monitoring with a calibrated thermometer. Do not exceed 10 °C above the freezing point during this period.
- Once the contents reach a temperature of approximately –20 °C, move the vials to a 20–25 °C water bath. Submerge the vials in a floating rack to avoid direct contact with the water surface.
- Maintain the water bath temperature between 20 °C and 22 °C. Stir gently to ensure uniform heat distribution. Thawing should be completed within 5–7 minutes; prolonged exposure can cause thermal shock.
- Immediately after thawing, remove the vials, disinfect the exterior with 70 % ethanol, and place the mice in a pre‑warmed recovery cage (30 °C) with appropriate bedding and enrichment.
- Provide access to sterile water and a nutritionally balanced diet. Observe the animals for at least 30 minutes for signs of distress, hypothermia, or abnormal behavior.
- Record the thawing time, temperatures, and any deviations from the protocol in the animal care log.
Key considerations:
- Avoid rapid temperature changes; gradual warming minimizes cellular damage.
- Use calibrated equipment to ensure temperature accuracy.
- Maintain aseptic technique throughout the process to prevent contamination.
- Ensure that recovery cages are pre‑conditioned to the target temperature before introducing the mice.
Following this detailed protocol supports optimal survival rates and physiological stability after thawing.