Objective: The aim of this study was to determine DNA damage during
euthymic and attack periods, and the oxidative metabolism states that
may cause this damage in the pathophysiology of bipolar disorder. The
role of DNA repair mechanisms in this process was also investigated.
Method: The study included a total of 90 patients aged between 18-65
years who were diagnosed with bipolar disorder according to DSM-
5 diagnostic criteria, with 30 patients in euthymic, 30 in manic and
30 in depressive periods. A control group was formed of 30 healthy
subjects matched to the patients by age, gender, body mass index and
smoking status and/or alcohol consumption. Oxidative metabolism was
investigated using the Comet Assay technique to assess DNA damage,
according to the oxidant/antioxidant status in the technique developed
by Erel with the Rel ASSAY Diagnostics kit (Turkey). The control and
patient groups were compared in respect of gene expression levels of
OGG1 and NEIL1 repair genes at mRNA level with Real-Time PCR.
Results: Increased DNA damage was found in the euthymic and
manic groups and decreased NEIL1 gene expression in the depressive
group. The oxidative stress index was found to be decreased in the
patient groups compared to the healthy control group.
Conclusion: Oxidative imbalance and DNA damage and repair
disorders may be effective in the pathophysiology of bipolar disorder.
Further studies on this subject are required to clarify the etiology and
new treatment goals.
Keywords: Bipolar disorder, oxidative stress, DNA damage, DNA
repair