DNA degradation in formalin-fixed tissues

The intensity of DNA degradation in fixed tissues is dependent on the fixation solution and the fixation time. The aim of this study was the investigation of DNA degradation over fixation times of up to 70 days in different tissues (muscle, brain, liver, bone) and with different formalin concentration (2%, 4%, 8%; unbuffered). An additional test was performed to see whether the fixed tissues could be individualized using PCR analysis. The smallest amounts of DNA were extracted from liver and brain and the largest from muscle and bone. The amount of DNA that could be extracted decreased with increasing formalin concentration, while at the same time DNA degradation increased. With the PCR-VNTR system HUMTH01, all fixed samples could be typed regardless of the fixation time and the formalin concentration.