Oxidative response of neutrophils to platelet-activating factor is altered during acute ruminal acidosis induced by oligofructose in heifers

• Published in: Journal of veterinary science (Suwŏn-si, Korea) Vol. 15; no. 2; pp. 217 - 224
• Main Authors: Concha, Claudia, Carretta, María Daniella, Alarcón, Pablo, Conejeros, Ivan, Gallardo, Diego, Hidalgo, Alejandra Isabel, Tadich, Nestor, Cáceres, Dante Daniel, Hidalgo, María Angélica, Burgos, Rafael Agustín
• Format: Journal Article
• Language: English
• Published: Korea (South) 대한수의학회 2014; The Korean Society of Veterinary Science
• Subjects: Acidosis - chemically induced; Acidosis - immunology; Acidosis - veterinary; Animals; Blood; Cattle; Cattle Diseases - chemically induced; Cattle Diseases - immunology; Female; Flow Cytometry - veterinary; Immunity, Innate; L-Selectin - metabolism; Neutrophils - drug effects; Oligosaccharides - pharmacology; Oligosaccharides - toxicity; Original; Platelet Activating Factor - pharmacology; Reactive Oxygen Species - metabolism; Rumen; 수의학; lactic acidosis; L-selectin; cow; neutrophils; reactive oxygen species
• ISSN: 1229-845X; 1976-555X
• DOI: 10.4142/jvs.2014.15.2.217

Reactive oxygen species (ROS) production is one of the main mechanisms used to kill microbes during innate immune response. D-lactic acid, which is augmented during acute ruminal acidosis, reduces platelet activating factor (PAF)-induced ROS production and L-selectin shedding in bovine neutrophils in vitro. This study was conducted to investigate whether acute ruminal acidosis induced by acute oligofructose overload in heifers interferes with ROS production and L-selectin shedding in blood neutrophils. Blood neutrophils and plasma were obtained by jugular venipuncture, while ruminal samples were collected using rumenocentesis. Lactic acid from plasma and ruminal samples was measured by HPLC. PAF-induced ROS production and L-selectin shedding were measured in vitro in bovine neutrophils by a luminol chemiluminescence assay and flow cytometry, respectively. A significant increase in ruminal and plasma lactic acid was recorded in these animals. Specifically, a decrease in PAF-induced ROS production was observed 8 h after oligofructose overload, and this was sustained until 48 h post oligofructose overload. A reduction in PAF-induced L-selectin shedding was observed at 16 h and 32 h post oligofructose overload. Overall, the results indicated that neutrophil PAF responses were altered in heifers with ruminal acidosis, suggesting a potential dysfunction of the innate immune response.