Inflammation-induced Changes in Serum Iron Analytes and Ceruloplasmin of Shetland Ponies

Abstract

A large number of hospitalized horses have low serum iron values but normal or high serum fenitin values6 In other species, several conditions including pregnancy, estrogen therapy, hypoproteinemia, and inflammation can cause serum iron to decrease in the absence of iron deficiency. Because low serum iron in hospitalized horses occurs in both sexes and in the absence of estrogen therapy and hypoproteinemia, the most likely cause of inappropriately low serum iron is inflamrnati~n.~ Acute localized inflammation can be initiated by injecting a small quantity of an imtant such as oil of turpentine. Because the effects of inflammation on iron metabolism have not been reported in horses, we have measured several ironrelated analytes during experimentally produced, localized inflammation in Shetland ponies. Eleven Shetland ponies were purchased from commercial sources. They were dewormed, vaccinated against equine encephalomyelitis, and quarantined for at least 2 weeks before the experimental period. On day 1, seven ponies were injected with 5 ml sterile oil of turpentine intramuscularly in the pectoral region. The remaining four ponies served as controls. Blood samples were taken immediately prior to injection and during the following 3 weeks. Serum iron and total iron binding capacity were determined coulometrically9 and serum ferritin by enzyme immunoassay with affinity-purified antibody.8 Serum ceruloplasmin was determined by p-phenylenediamine oxidization.2 Serum copper was determined by atomic absorption. Statistical significance was determined by analysis of variance. Significant treatments were located by least significance difference. l o