EICOSANOID CONCENTRATIONS IN DIGITAL VENOUS-BLOOD FROM HORSES WITH CHRONIC LAMINITIS

The eicosanoids are a family of lipid-derived autocoids that are relea sed in response to a variety of physical and hormonal stimuli. In this study, prostaglandin E(2) (PGE(2)) and leukotriene B-4 (LTB(4)) were measured in the digital veins of clinically normal horses and horses w ith chronic laminitis to determine whether these arachidonic acid meta bolites have a role in mediating signs of hoof pain and lesions associ ated with chronic laminitis. Horses were evaluated at rest and after a brief exercise period, to determine whether eicosanoids are released into the circulation after mild concussion. Digital vein eicosanoid co ncentrations in horses with signs of hoof pain attributable to chronic laminitis were not different than those in clinically normal horses. There was no difference in resting and postexercise PGE(2) or LTB(4) c oncentrations. Mean digital vein PGE(2) concentration for the 2 groups was 187.18 pg/ml, whereas mean digital vein LTB(4) concentration for the 2 groups was 74.71 pg/ml. These data do not support the hypothesis that PGE(2) and LTB(4) have a role in mediating the signs of pain and pathologic features of chronic laminitis.