Enzimas relacionadas ao estresse oxidativo após desafio com endotoxina exógena

Abstract

Ruminants have the ability to adapt to imposed conditions. However, sometimes the stress status changes presenting ruminants oxidative stress. Therefore, the objective of this study was to verify the serum levels of enzymes involved in oxidative stress, which was induced by two infusions of lipopolysaccharide (LPS), in order to cause an experimental inflammation. Sixteen European heifers were accompanied. Their ages were around 14 months, weighing approximately 330 kg, clinically healthy, managed in an intensive system and with free access to water. The LPS group (n = 8) received 2 intravenous applications (iv) containing 0.5 μg/kg of body weight of LPS (Sigma Aldrich Missouri, USA) diluted in 2 mL of saline solution (0.9% NaCl), with an interval of 24 hours (known peak time of the inflammatory response occurrence). The control group (n = 8) received the same applications and dosages of saline solution (0.9% NaCl) via i.v, within the same interval. General clinical and blood tests were performed at 0, 4 and 8 hours after two challenges with LPS, being hour 0 the time of LPS infusion or saline solution. Blood was collected through the coccygeal arteriovenous complex using the Vacutainer system (BD Diagnostics, São Paulo, Brazil). After collection, the tubes were centrifuged and the serum was stored for further analysis. The body temperature of the LPS group was higher four hours after each challenge (P & lt; 0.05). The total leukocyte count was lower in the LPS group (P & lt; 0.05). Heart rate was also affected by the challenge with LPS (P & lt; 0.05) and respiratory rate did not differ between groups. The activity of total-SH (P = 0.084) and EROS (P = 0.050) showed a statistical trend. It was found that the challenge with two applications of LPS demonstrated changes in the serum production of total-SH and EROS.