EN
There are some hypotheses that oxidative damage to DNA secondary to infl ammation may contribute to irreversible alterations in MS plaques. To test this assumption, we have estimated the level of a DNA oxidative marker, the level of a purine oxidation product, the 8-oxo-2-deoxyguanosine (8-oxo-2dG) in lymphocytes of MS patients. Material and methods: Peripheral blood was collected from 28 patients with clinically defi nite MS aged from 19 to 46 years. The duration of MS was 4.2 ± 3.1 years. The mean of EDSS was 2.0 ± 0.8. In MRI study 14 cases were gadolinium positive and 14 negative. Thirty healthy volunteers make up the control group. DNA was isolated from peripheral blood lymphocytes and then hydrolyzed to nucleosides using P1 nuclease. In order to determine 8-oxo-2dG level, the nucleoside mixture was applied to the HPLC/ UV system, coupled to an electrochemical detector. Results and discussion: The mean level of 8-oxo 2dG in MS patients was 19.6 ± 35.1 and, compared to that established for control subjects (12.3 ± 7.2), showed no statistically signifi cant differences. The comparison of 8-oxo-2dG in subgroups of patients divided according to duration of the disease showed the higher number of cases with DNA damage in patients of the subgroup with shorter duration of the disease. The mean level of 8-oxo-2dG in gadolinium positive MS cases was 17.3 ± 13.1 and in gadolinium negative ones it was 9.6 ± 4.0. The difference was signifi cant. Conclusions: (1) Oxidative damage to DNA is not a general feature in MS patients but it may frequently appear in the early period of the disease; (2) The higher level of oxidative marker of DNA damage in MS, noted in active period of the disease, testifi es to the relationship between the studied variable and MS process.