Assessment of Oxidative Stress and DNA Damage in Dogs with Visceral Leishmaniasis Using Urinary...

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.