Assessment of exercise-induced alterations in neutrophil function in horses.

OBJECTIVE: To evaluate the effects of a standardized exercise test to exhaustion in horses on leukocyte function ex vivo. ANIMALS: 6 Thoroughbred geldings. PROCEDURES: Blood samples were obtained from each horse before exercise; at exhaustion (termed failure); and at 2, 6, 24, 48, and 72 hours after exercise to evaluate hematologic changes, rate of leukocyte apoptosis, and leukocyte production of reactive oxygen species (ROS) ex vivo. To assess leukocyte function, leukocyte ROS production in response to stimulation with lipopolysaccharide, peptidoglycan, zymosan, and phorbol myristate acetate was evaluated. Apoptosis was evaluated via assessment of caspase activity in leukocyte lysates. RESULTS: In response to lipopolysaccharide, production of ROS by leukocytes was significantly increased at 2 hours and remained increased (albeit not significantly) at 6 hours after exercise, compared with the preexercise value. In the absence of any stimulus, leukocyte ROS production was significantly increased at 6 and 24 hours after exercise. In contrast, ROS production in response to phorbol myristate acetate was significantly decreased at 6, 24, and 72 hours after exercise. Leukocyte ROS production induced by zymosan or peptidoglycan was not altered by exercise. Leukocytosis was evident for 24 hours after exercise, and neutrophilia was detected during the first 6 hours. A significant increase in the rate of leukocyte apoptosis was detected at failure and 72 hours after exercise. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that strenuous exercise undertaken by horses causes alterations in innate immune system functions, some of which persist for as long as 72 hours after exercise.

Assessment of neutrophil chemotaxis and random migration in children and adults. Comparison between filter and agarose techniques.

Polymorphonuclear leucocyte migration was studied in 16 children and 11 normal adults, both by a filter technique and under agarose. Assays were carried out in parallel. There were no significant differences (p greater than 0.5) between adult controls and children's mean neutrophil migration coefficients within methods, but highly significant differences were found between methods (p less than 0.001) both in adult and children's samples. The observed intermethod differences are shown to be the result of increased random migration under agarose in both age groups.