Modulation of TNF-α, IL-1Ra and IFN-γ in equine whole blood culture by glucocorticoids

Glucocorticoids are important drugs in the treatment of many inflammatory, autoimmune and allergic diseases in humans and animals. We investigated the effects of hydrocortisone and dexamethasone on TNF-alpha, IL-1Ra and INF-gamma release in stimulated whole blood cell culture from healthy horses. Whole blood cell cultures proved to be useful for the characterization of the anti-inflammatory properties of new drugs. Diluted equine whole blood was exposed to lipopolysaccharide (LPS) and PCPwL (a cocktail consisting of phythemagglutinin E, concanavalin A, pokeweed mitogen and lipopolysaccharide) in the presence or absence of hydrocortisone and dexamethasone (10(-12 )- 10(-5) M). TNF-alpha and IL-1Ra (LPS) as well as IFN-gamma (PCPwL) levels were measured in the supernatants using specific enzyme-linked immunosorbent assay (ELISA). The LPS-induced TNF-alpha and IL-1Ra as well as the PCPwL-induced IFN-gamma levels were more potently suppressed by dexamethasone than by hydrocortisone in a concentration-dependent manner. Dexamethasone inhibited TNF-alpha, IL-1Ra and IFN-gamma with the half maximal inhibition concentration (IC50) values of 0.09 mu M, 0.453 mu M and 0.001 mu M, respectively, whereas hydrocortisone inhibited these cytokines with lower IC50 values of 1.45 mu M, 2.96 mu M and 0.09 mu M, respectively. Our results suggest that the equine whole blood test system is useful and reliable to evaluate drug effects and immunological alterations and offers several advantages including simple and cheap performance in physiological and pathological conditions.