3-nitrotyrosine and Foot-Diseases

Tissue damage caused by oxidative stress is involved in the pathogenesis of several diseases in animals and man, and is believed to play a role in the development of laminitis in horses. The aim of this study was to investigate the oxidative stress associated with laminar lesions in horses with lethal gastrointestinal disorders. Laminar tissue samples of the hoof of 30 horses were used. Tissue samples were divided as follows: six healthy horses (control group-CG), and 24 horses that died after complications of gastrointestinal diseases (group suffering from gastrointestinal disorders-GDG). Superoxide dismutase (SOD2) and nitrotyrosine immunostaining and the severity of laminar lesions were evaluated. Presence of laminar lesions and immunostaining for nitrotyrosine and SOD2 were only evident in horses from the GDG group. Thus, oxidative stress may play a role in the pathogenesis of laminar lesions secondary to gastrointestinal disorders.

Topics: Animals; Female; Foot Diseases; Gastrointestinal Diseases; Hoof and Claw; Horse Diseases; Horses; Male; Oxidative Stress; Superoxide Dismutase; Tyrosine

Inflammatory and redox signals could render lamellar tissue susceptible to damage and contribute to higher risk for laminitis in obese or insulin resistant ponies just as these factors contribute to health risks in humans with metabolic syndrome. This study evaluated circulating markers of inflammatory and redox status in ponies that had a history of recurrent bouts of pasture-associated laminitis (PL, n = 42) or had never developed clinical laminitis (NL, n = 34) under the current management conditions. There were no differences (P > 0.05) between PL and NL ponies for markers of antioxidant function (glutathione, glutathione peroxidase, superoxide dismutase) or increased oxidative pressure (malondialdehyde, apoptosis, 3-nitrotyrosine). Inflammatory status, as indicated by fibrinogen concentration, was also not different between pony groups (P = 0.84). However, PL ponies had higher (P < 0.001) plasma concentrations of the pro-inflammatory cytokine TNF-alpha than NL ponies. This suggests that a predisposition to laminitis is associated with increased circulating inflammatory cytokines. TNF-alpha could also represent a contributing factor to increased insulin resistance observed in laminitis prone ponies. These results provide new insight into potential mechanisms and risk factors underlying laminitis.

Topics: Aging; Animal Husbandry; Animals; Cytokines; Female; Foot Diseases; Hoof and Claw; Horse Diseases; Horses; Inflammation; Oxidation-Reduction; Risk Factors; Superoxide Dismutase; Tyrosine