Cell death and apoptosis regulating proteins in Parkinson's disease a cautionary note

We studied the substantia nigra of three Parkinson's disease (PD) patients and three age-matched individuals by in situ DNA-end labeling (ISEL) and im muno-histochemistry for the apoptosis regulating proteins Bcl-2, Bar and Bc l-x on 50 consecutive sections per patient. No melanin-containing cell was identified with typical apoptotic changes in either patient or control subs tantia nigra. With prolonged reaction-time the terminal transferase-mediate d DNA-end labeling revealed a signal in 2.0 +/- 1.2% melanin-containing cel ls in PD compared to 1.3 +/- 1.1% in control. This difference did nor reach statistical significance and no condensation or margination of the chromat in was evident. No significant changes of any of the apoptosis regulating p roteins were apparent in PD substantia nigra. These findings do not support the hypothesis that apoptosis plays a central role in the pathogenesis of PD.