LAUSR

&NA; Equine platelet‐rich plasma (PRP) has been used in horses to repair bone, articular and tendinous lesions, laminitis, and even endometritis. However, platelets have a very limited lifespan, which makes it difficult to prepare and use PRP, except in loco. With the aim to produce PRP with higher platelet viability for clinical purposes, the effects of the cryoprotectants dimethyl sulfoxide (DMSO) and trehalose were evaluated on cooled (4°C) and cryopreserved (−196°C) equine PRP. The protocols of cooling and cryopreservation were performed independently, comparing the following treatments: fresh PRP, PRP + 6% DMSO, PRP + 300 mM of trehalose, and PRP only. The PRP samples were prepared by double centrifugation of the blood of six ponies, further divided into four aliquots. The cooled or cryopreserved aliquots were stored for 14 days. All samples were evaluated for the platelet count, the mean platelet volume, and the release of transforming growth factor beta 1 (TGF‐&bgr;1). The number of platelets in the fresh PRP and cooled samples was similar; however, platelet count was higher in the fresh PRP than in cryopreserved samples. The release of TGF‐&bgr;1 was higher in the fresh PRP (105891 ± 52398 pg/mL), but the stored samples still released significant amounts of this growth factor (27291 ± 9625 pg/mL).