The relationship between oxidative stress markers and visual evoked potentials in different hypertension models

Objective: We aimed to define the influence of different hypertension models on lipid peroxidation markers [conjugated dienes (CD) and thiobarbituric acid-reactive substances (TBARS)], antioxidant protection [paraoxonase-1 (PON1) activity] and visual evoked potential (VEP) changes in rats. Methods: The study was designed as four different hypertension models. Rats (n=84) were divided equally into six groups: Control group (C), Sham operated (Sham), Two kidney-one clip (2K-1C), One kidney-one clip (1K-1C), Deoxycorticosterone acetate (DOCA) and N-omega-nitro-Larginine- methyl ester (L-NAME). Brain TBARS, serum lipids (total and lipoprotein bound cholesterols and triglycerides) CD and TBARS levels and PON1 activity were assayed. Comparisons were performed using ANOVA or Wilcoxon/Kruskal-Wallis tests. Pearson correlation and linear regression analysis were used to evaluate associations of independent predictors with hypertension. Results: Mean arterial pressure, brain and serum lipid peroxidation markers, VEP latencies were significantly higher in four hypertensive groups compared with control and sham groups (p 0.05). Compared with controls, PON1 activity was decreased in DOCA, 1K1C and L-NAME groups (p 0.05). Serum PON1 activity was negatively correlated with lipid peroxidation markers and VEPs. In terms of VEP s records linear regression analysis showed that changes in N2 (B=1.51±0.34; p 0.001), P1 (B=-1.71±0.28; p 0.001), P3 (B=0.54±0.14; p 0.001), serum TBARS levels (B=0.94±0.24; p 0.001) and PON1 activity (B=0.05±0.02; p 0.01) were independently associated with elevated blood pressure. Conclusion: Lipid peroxidation measured in serum and brain was associated with increased electrophysiological alterations recorded as VEPs. This study might suggest that serum PON1 activity may be protective against brain and serum lipid peroxidation as well as electrophysiological alterations in the brain in different hypertension models.