Eicosanoid concentrations in digital venous blood from horses with chronic laminitis

The eicosanoids are a family of lipid-derived autocoids that are released in response to a variety of physical and hormonal stimuli. In this study, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were measured in the digital veins of clinically normal horses and horses with chronic laminitis to determine whether these arachidonic acid metabolites have a role in mediating signs of hoof pain and lesions associated 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 concentrations 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 PGE2 or LTB4 concentrations. Mean digital vein PGE2 concentration for the 2 groups was 187.18 pg/ml, whereas mean digital vein LTB4 concentration for the 2 groups was 74.71 pg/ml. These data do not support the hypothesis that PGE2 and LTB4 have a role in mediating the signs of pain and pathologic features of chronic laminitis.