Abstract
Platelet rich plasma (PRP) is an autologous biological product harvested by consecutive centrifugations of whole blood and separation of plasma in a stepwise protocol. PRP has been successfully used to stimulate healing in orthopedic and dermatological conditions, both in humans and animals. The principle is the fact that α- granules inside platelets contain a high concentration of growth factors, that once released can interfere with cellular communication and speed up healing. Standardization of PRP requires establishing a gold standard for the preparation and evaluation of the product, especially considering that platelet concentration and, therefore, growth factor concentration, might vary due to a number of variables. Factors such as age, gender, race or breed, and immune status of the patient might interfere with PRP quality and with treatment results, although little is known about such interferences. This research investigated the effect of breed/species and gender in platelet concentration in autologous PRP from horses and mules. The results demonstrate that Quarter Horses provided PRP with the greatest amount of platelets, although mules had a higher concentration percentages in relation to the initial platelet counts.