# Assessment of Oxidative Stress and DNA Damage in Dogs with Visceral Leishmaniasis Using Urinary 8-Hydroxy-2′-Deoxyguanosine

## TL;DR

This study found that dogs with visceral leishmaniasis show signs of oxidative stress but no significant DNA damage in urine, suggesting oxidative balance is disrupted but DNA damage markers may not be reliable.

## Contribution

The study provides new insights into oxidative stress in canine leishmaniasis and questions the reliability of urinary 8-OHdG as a DNA damage marker in this disease.

## Key findings

- Dogs with leishmaniasis had significantly higher total antioxidant and oxidant capacity compared to healthy dogs.
- Urinary 8-OHdG and MDA levels were higher in infected dogs but not statistically significant.
- Oxidative balance is disturbed in dogs with leishmaniasis, but urinary DNA damage markers may not be reliable.

## Abstract

Canine leishmaniasis is an important parasitic disease that affects dogs and can also be transmitted to humans. This disease can cause oxidative stress, which may damage cells and DNA. In this study, we evaluated oxidative stress and DNA damage in dogs with leishmaniasis by measuring oxidative stress markers in blood and a DNA damage marker in urine. We found that dogs with leishmaniasis exhibited alterations in oxidative balance, characterized by increased total oxidant capacity (TOC) along with a concurrent increase in total antioxidant capacity (TAC), but urinary DNA damage levels were not significantly different from healthy dogs. These results suggest that oxidative stress is involved in the disease, while urinary DNA damage markers measured by ELISA may not be reliable diagnostic tools.

Canine leishmaniasis (CanL) is a major vector-borne disease with zoonotic potential, and oxidative stress plays an important role in its pathogenesis. CanL is a chronic, progressive disease in which clinical signs may develop gradually over months or even years, depending on host immune response and parasite burden. This study aimed to evaluate oxidative DNA damage in dogs with CanL by measuring urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels and oxidative stress markers. A total of 54 dogs, including 34 dogs with CanL and 20 healthy controls, were included. Urinary 8-OHdG and serum malondialdehyde (MDA) were measured using ELISA method, whereas serum TAC and TOC were determined using automated colorimetric method. Dogs with CanL showed significantly higher TAC (1.30 ± 0.05 vs. 1.04 ± 0.06 mmol/L, p = 0.001) and TOC levels (18.91 ± 3.29 vs. 8.23 ± 1.61 μmol H2O2 Eq/L, p = 0.002) compared with healthy controls. Although urinary 8-OHdG and MDA levels were higher in infected dogs, these differences were not statistically significant (p > 0.05). These findings indicate a disturbance in oxidative balance in dogs with CanL, characterized by simultaneous increases in both oxidant and antioxidant parameters, while urinary 8-OHdG, as measured by ELISA, may have limited ability to reflect cellular oxidative DNA damage in dogs with CanL, rather than indicating an absence of DNA damage.