Detection of apoptotic DNA damage in prostate hyperplasia using tyramide-amplified avidin-HRP

Avidin binds to damaged DNA with high specificity. Avidin conjugated to horseradish peroxidase may therefore be used to label apoptotic DNA damage, using standard immunohistochemical protocols. However, the resulting label may be too weak to visualise. We used tyramide signal amplification to enhance the avidin-peroxidase signal in a rat model of apoptotic damage in hyperplasic prostate tissue. After amplification, the difference between normal levels of apoptosis in the young rat prostate and the greatly reduced levels evident in aged rats was readily appreciated. The label was specific and the non-specific background was minimal. This method is particularly useful for the detection of weak apoptotic signals in tissue sections.