Effects of infection intensity with Strongyloides papillosus and albendazole treatment on development of oxidative/nitrosative stress in sheep.

The objective of this study was to estimate and evaluate oxidative/nitrosative stress parameters in sheep infected with Strongyloides papillosus and after antihelminthic treatment with albendazole (ABZ). This parasite, especially during development stages can seriously damage parenchaematous organs during migration within the host. The presence of parasites leads to increased productions of reactive oxygen species (ROS) and reactive nitrogen species (RNS). It is also well known that certain drugs can be very harmful for the delicate oxidant-antioxidant equilibrium, provoking oxidative stress during their biotransformation. ABZ is a broad spectrum antihelminthic drug, frequently used in veterinary medicine for therapy of parasitic infections. The current research was performed on female Württemberg sheep (n=48). The distribution of parasites in sheep was evaluated using the native smear coprological technique, by sedimentation and flotation methods, revealing the presence of S. papillosus. The degree of infection intensity per sheep was quantitatively established by the method of McMaster, the animals having been divided into three groups according to the intensity of infection; mild, moderate and high. The control group consisted of sheep negative to the parasites. After determining the type of parasite infection, the sheep were treated with ABZ, per orally, in single doses of 5mg/kg per body weight. Sampling of feces for parasitological and blood for biochemical assaying was performed on the 0 and 21st day after treatment with ABZ. The oxidative stress parameters were measured for catalase activity (CAT), the red cell membrane damage by level of malondialdehyde (MDA), while carbonyl and thiol plasma protein group concentrations were used as indicators of the degree of protein oxidative modification. The activity of Cu,Zn-superoxide dismutase (SOD) and relative distribution of lactate dehydrogenase (LDH(1)-LDH(5)) activity were determined electrophoretically. The distribution of LDH isoenzymes in sheep moderately and highly infected with S. papillosus revealed that the parasite induced damage to the myocardial (LDH(2)), lung (LDH(3)) and liver cells (LDH(5)) in infected animals, while ABZ treatment only damaged liver cells (LDH(5)). The MDA concentration revealed that lipid peroxidation increased both in the presence of parasites and the antihelminthic formulation tested (p<0.001) when compared to the control sheep, while the increase of carbonyl concentration (p<0.001), as well as the observed decrease of thiol concentration (p<0.001) indicated significant oxidative damage of plasma proteins in experimental sheep, when compared to the control animals. Our results indicate that S. papillosus induces oxidative/nitrosative stress in sheep. The antihelminthic treatment with ABZ further promotes the disbalance of oxidative-antioxidative equilibrium in all tested sheep.