Apoptosis signals in sporadic amyotrophic lateral sclerosis: an immunocytochemical study.

Sporadic amyotrophic lateral sclerosis (sALS) is a neurodegenerative disorder of unknown cause characterized by selective loss of both upper and lower motor neurons. Whether neuronal death in sALS is due to apoptosis has so far not been clarified. In this study, the expression and distribution patterns of pro- and anti-apoptotic bcl-2 family members as well as the executioner caspase-3 were investigated in post-mortem CNS tissue of eight sALS patients and seven age-matched controls. Sparse motor neurons were immunoreactive for bcl-2, bax, bak, and CM1 on serial sections through the spinal cord and motor cortex of individual sALS patients and controls. However, there was no obvious difference in the numbers of immunoreactive (IR) neurons between the two groups. The study did not find evidence for apoptosis as a major mechanism of motor neuronal cell death in sALS.