Cryogenic refrigerator manufacturers under the present commonly used animal tissue preservation method has low temperature freezing method, soaking method of formaldehyde, paraffin embedding method and the ethanol soak method, etc. , have their own features and advantages and disadvantages of different preservation method.
Animal tissue preserved for a long time is for DNA sequencing, molecular genetics and forensic identification of important premise, animal tissue preservation directly influences the quality of DNA extraction yield and quality of the late.
low temperature freezing method using low temperature (
20 ℃ low temperature refrigerator, --
80 ℃ cryogenic refrigerator or -
196 ℃) in liquid nitrogen
Inhibition of the DNA enzyme activity to long-term preservation organization DNA, it is better to save the method, but its preservation condition strictly, save cost and easily affected by power failure accident such as high.
formaldehyde soaking method with formaldehyde DNA enzyme inactivation and preservation of DNA, this method has a better fixation for animal tissues.
But formaldehyde makes serious crosslinked proteins and DNA, DNA make it difficult to completely release from the organization, in addition, formaldehyde can also cause a genomic DNA fragmentation and decorate, lead to the late segments of DNA extraction process is difficult to get a lot of complete.
In addition, the formaldehyde has very strong toxicity, this method has a potential hazard to the operator.
paraffin embedding method is also the animal samples preserved the traditional method, but its paraffin, embedding and storage processes is unrecoverable damage to the DNA in animal tissues.
The method also need to use the formaldehyde, so late can also cause the difficulty of DNA extraction.
ethanol soak osmosis method using ethanol to animal tissue dehydration, DNA enzyme inactivation and save the DNA.
Although ethanol to osmosis organization quickly and nonpoisonous and harmless, but research has shown that for a long time stored in animal tissues of ethanol will loose dispersion, lead to save less tissue block, ethanol would have cutting effects on genomic DNA, forming small fragments of DNA length, easy to volatilize and ethanol, ethanol concentration decreased after long-term preservation, cannot achieve good preservation effect.