Incorporation of L-75Se-cystine in tissue fragments from the matrix of the hoof and the claw--a tool for studying the pathogenesis of laminitis?

An in vitro method has been designed and used to study the incorporation of 75Se-cystine into matrix fragments from hooves and claws of healthy horses and cattle. Tissue fragments from the zone of keratinisation were incubated with L-75Se-cystine in a tissue culture medium for 4 to 6 h, during which time there was continuous incorporation of the labelled selenocystine. The incorporation was greatly decreased by adding L-cystine to the incubation mixture. It is concluded that the incorporation of 75Se-cystine depends on the presence of a specific receptor for cystine in the tissue fragments studied. The possible application of the method to studies of the pathogenesis of laminitis is discussed.