The study aimed at the analysis of polymorphisms in the gene coding for the
nicotinic acetylcholine receptor alpha4 subunit (CHRNA4) and the evaluation of the extent of the oxidative damage to
DNA (8-oxo2dG), as well as the level of
proteins participating in DNA repair (p53, PARP) and
DNA degradation (Bax:Bcl-2, 85-kDa fragment) in the peripheral blood lymphocytes of the patients suffering from
Alzheimer's disease (AD) and in the healthy individuals of the control group. In the AD patients the increased levels of oxidized
guanine were demonstrated in
DNA, accompanied by the elevated expression of p53, Bax, PARP, and of a 85-kDa
protein subunit as well as an augmented ratio of Bax:Bcl-2. Also, the level of Bcl-2
protein was decreased. In the AD patients with the CHRNA4 polymorphisms the highest level of 8-oxo2dG and of
proteins involved in DNA repair were documented in patients with polymorphisms in exon 5, in contrast to the patients with polymorphisms in intron 5. In the former patients, levels of pro- and antiapoptotic
proteins remained at the same level. Both CHRNA4 polymorphisms and the extent of
dementia seem to affect the levels of DNA oxidative damage as well as to activate factors that participate in the
DNA degradation and its repair.