形成原因包括: 冰晶傷害，冷凍解凍液毒性&傷害，滲透壓，溫度, etc
http://humrep.oxfordjournals.org/content/17/7/1863.full
Figure 2.
The appearance of mouse blastocysts after vitrification by the control method (A) or after being injured by various mechanisms. Embryos with intracellular ice (B). Embryos subjected to the cryoprotectant toxicity by exposure to EFS40 at 25°C for 10 min without cooling (C), exposure to EFS40 at 25°C for 5 min followed by vitrification (D), exposure to EFS40 at –20°C for 3 h (E), or exposure to EFS40 at 25°C for 60 min (F). Embryos injured by osmotic swelling without cooling (G) or after vitrification (H). Embryos injured by osmotic shrinkage without cooling (I) or after vitrification (J). Embryos with fracture damage (K), and those injured by extracellular ice (L). Photographs of the same embryos were taken after recovery in sucrose solution (1: left) and in PB1 medium (2: second left), and after culture for 1 h (3: second right) and 24 h (4: right), except for those in (G) and (I) where photographs of different embryos were taken in sucrose solution. For fracture damage, the embryos in each photograph may not be the same because 10 embryos were vitrified for observation. Magnification ×165.
Morphological appearance of the cryopreserved mouse blastocyst as a tool to identify the type of cryoinjury
+Author Affiliations
- Received October 29, 2001.
- Accepted March 8, 2002.
Abstract
BACKGROUND: If it were possible to deduce the mechanism of injury in cryopreserved embryos by their appearance, it would help to optimize cryopreservation protocols. METHODS: Mouse blastocysts were treated so that they were damaged by the six types of cryoinjuries listed below, and their appearance was observed at recovery in sucrose solution and a modified phosphate-buffered saline (PB1), and after culture for 1 and 24 h. RESULTS: (i) Intracellular ice: the embryos shrank normally in sucrose solution, but swelled in PB1 and collapsed after culture. (ii) Chemical toxicity of the cryoprotectant: the embryos looked normal in sucrose solution and PB1. After 1 h of culture, however, the blastomeres showed decompaction and degenerated thereafter. If the toxicity was extremely high, embryos looked nearly normal in PB1, but the surface of the cytoplasm was wrinkled as if they were `fixed'. (iii) Osmotic swelling: the embryos looked normal in PB1, but after culture they shrank. (iv) Osmotic shrinkage: the embryos swelled in PB1, and then collapsed. (v) Fracture damage: the zona pellucida of the embryos was dissected. (vi) Extracellular ice: the zona of the embryos was elongated. CONCLUSIONS: It was often possible to deduce the type of injury that had occurred in cryopreserved embryos from their appearance at recovery and during subsequent culture. This may help to improve cryopreservation protocols for embryos of many species, including man.
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