Avaliação morfológica do concentrado autólogo de plaquetas de cão sob refrigeração e criopreservação em DMSO 6%

Abstract

The objective of this study was to evaluate the morphological characteristics of autologous platelet concentrate (APC) in the dog, after refrigeration and freezing. Thirty-one dogs (20 females and 11 males) of different races and ages were submitted to the Veterinary Hospital of the Federal University of Minas Gerais (UFMG) for orthopedic treatment with indication of cellular therapy. 9 mL of jugular vein blood were collected, seven mL were deposited in 8.5 mL tubes containing ACD-A as anticoagulant to obtain APC and two mL in one tube with EDTA for platelet count, mean platelet volume (MPV) and platelet distribution width (PDW). The blood was centrifuged at 191 g for 6 minutes (single centrifugation) to obtain APC. In the fresh sample, the platelet count, MPV, PDW and cell morphology were evaluated. The morphological evaluation was performed by counting 200 platelets under optical microscopy that were classified as inactive (discoid form), uncertain (loss of discoid shape without pseudopodia) and activated (with pseudopod emission). Four samples of each animal were sent for storage, one refrigerated at 4 ° C for seven days, one for 30 days and two stored in a freezer at -80 ° C in the same time interval using 6% dimethyl sulfoxide (DMSO) as cryoprotectant. After this period, the samples were thawed in a 37°C water bath and, as the refrigerated ones, were subjected to the same laboratory analysis as the fresh sample. There was a difference between fresh and preserved samples for platelet count, cell concentration, MPV and PDW (P<0.05), except in the group refrigerated for 30 days, which showed severe morphological alterations. In the frozen group for seven days, no difference was observed in the percentage of activation (P>0.05). The results obtained lead to the conclusion that cryopreservation with 6% DMSO at -80 ° C for seven days is a favorable option for the maintenance of platelet concentrations and the morphological characteristics of APC in dogs.