The fundamental studies on the effect of formalin fixation on DNA

通过分析福尔马林固定对动物和身体肝组织中DNA和DNA的影响，研究了福尔马林固定对DNA的影响：(1)通过过夜固定，福尔马林在室温下特别是在酸性和无盐的条件下将DNA裂解成小片段，尽管在4ﾟC的中性条件下缓冲的福尔马林(BF)可以防止DNA断裂。另一方面，λ噬菌体DNA对各种限制性内切酶产生了抗性。这一影响依赖于温度，但不依赖于福尔马林溶液的盐浓度。因此，这两个现象被认为是福尔马林的独立效应，前者可能是由于磷酸-酯结合的断裂，而后者可能是由于DNA碱基上的氨基之间的交联所致。无论这些影响如何，Lambda-DNA在10%福尔马林中固定2周，在BF中固定4周，以及肝组织DNA在10%福尔马林中室温固定6个月，PCR分析都是成功的。因此，在4ﾟC的BF中短时间固定是保存病理标本DNA的最佳固定方法。

The effect of formalin fixation on DNA was studied by analysing the effects on lambda-DNA and DNA in animal and autopsied liver tissues.(1)By over-night fixation, formalin split DNA into smaller pieces especially in acidic and saltless conditions at room temperature, although bufferred formalin (BF) in neutral at 4ﾟC prevented DNA fragmentation. On the other hand, lambda-phage DNA became resistent to various restriction enzymes. This effect was dependent on temperature but not on salt concentration of the formalin solution. Thus, these 2 phenomena was considered to be an independent effect of formalin probably caused by scission of phosphate-ester binding for the former, and by cross-linking between the amino groups of the DNA bases for the latter. Regardless of these effects, PCR analysis was successful with lambda-DNA fixed for 2 weeks in 10% formalin and 4 weeks in BF, and with DNA in liver tissues fixed for 6 months in 10% formalin at room temperature. Thus, fixation in BF at 4ﾟC for a short time was recommended as the best fixation method for preservation of DNA in pathology specimens.