Effects of hydrocortisone on platelet aggregation in jumper horses

Research conducted in human sports medicine showed the variable effect of exercise on platelet aggregation parameters, which consist, for some authors, in a significant increase of aggregation, while for others, in its decline as result of physical activity. The purpose of our study was to test, in athletic horses, the effect of hydrocortisone as an anti-inflammatory steroid drug as an inhibitor of platelet aggregation in vitro. In our research a total of 12 jumper horses, 4 females and 8 geldings (Sella Italiana breed), clinically healthy, specifically trained and in good nutritional condition, were divided into two groups (A and B). From all the blood samples, collected in tubes containing sodium citrate (1 part sodium citrate to 9 parts blood), platelet aggregation was evaluated adding adenosine diphosphate (ADP) as a platelet-activating agent, and also after incubation for 20 minutes with hydrocortisone (IDR) as an inhibitor of platelet aggregation. Using an aggregometer platelet aggregation curves were defined and from these the aggregation rate and the slope of aggregation were evaluated. Multivariate ANOVA showed the significant effect of time (P<0.05) on platelet aggregation and on the average speed of aggregation (P<0.05). The effect of hydrocortisone was observed only on the aggregation slope (P<0.01). Further research should be conducted to assess the effective sensitivity of the slope, and certainly, given the absent effect of hydrocortisone on the platelet aggregation, another kind of anti-aggregation substance should be used to compare our data.