Comparative analysis of antioxidant status in Lewis and SHR inbreed rat strains

The inbred rat strains Lewis (LEW) and Spontaneously Hypertensive Rats (SHR) are known for their genetically determined differences in anxiety-related behaviors and blood pressure levels. However, the relationship between these variables remains unclear, with some researchers suggesting that oxidative stress and antioxidant systems may play a crucial role in their regulation. To explore this, several oxidative stress biomarkers were evaluated in the brain and liver of both male and female LEW and SHR rats. In the brain, LEW male rats exhibited lower levels of reduced glutathione (GSH), total glutathione (GT), glutathione reductase (GR) and glutathione S-transferase (GST) activity, and higher glutathione peroxidase (GPx) activity compared to SHR males. LEW females had lower GSH, GT, catalase (CAT) and GST activity, and higher GPx activity than their SHR counterparts. Additionally, males, regardless of strain, showed lower levels of thiobarbituric acid reactive substances and GPx activity, but higher GSH levels and GT activity compared to females. Conversely, in the liver, there were no significant differences in GSH activity, but interactions between strain and sex were observed for all other biomarkers evaluated. Overall, the results indicate that LEW rats have a lower brain antioxidant capacity compared to SHR rats, while the liver data are more variable. This constitutively lower antioxidant profile in the brain of LEW rats, observed in both sexes, may be correlated with their high anxiety/emotionality behavior, when compared to the SHR rats.