Digital Expression of Isoforms of Cyclooxygenase in a Model of Bovine Laminitis

Abstract

A great deal of the proposed pathophysiology of bovine laminitis is extrapolated from data obtained from equine laminitis. Similar to its equine counterpart, bovine laminitis commonly occurs secondary to conditions associated with endotoxemia (i.e. carbohydrate overload and mastitis). However, due to differences in clinical presentations of laminitis in the two species, our laboratory is interested to discern if the same pathophysiologic mechanisms take place in the two different species. Our laboratory has provided evidence that the developmental period of laminitis is an inflammatory event in horses. Specifically, we have demonstrated the upregulation of interleukin-Iβ (IL-1β) locally in equine laminae and systemically in mesenteric lymph nodes in the early stages of laminitis. Our lab also found increased COX-2 expression in equine laminae in horses in the developmental stage of black walnut extract-induced laminitis. Cyclooxygenase (COX) is the key enzyme in the process of converting arachidonic acid to eicosanoids. Downstream eicosanoid synthesis resulting from COX upregulation during laminitis may account for the aberrant vascular events occurring in the digit during this condition. The purpose of our project was to determine if cyclooxygenase isoforms (COX-1 and COX-2) were similarly affected in the laminitic bovid.