Healing and expression of growth factors (TGF-β and PDGF) in canine radial ostectomy gap containing platelet-rich plasma

Objectives: To evaluate bone healing in an experimental radial ostectomy in dogs treated with autologous platelet-rich plasma (PRP), through histological, densitometric, radiographic studies, as well as expression of growth factors in the ostectomy gap. Methods: Twenty-one dogs were randomly divided into either a control or a PRP group. All underwent unilateral ostectomy of the radius to generate a gap of 2.0 mm, that was stabilized with external skeletal fixation. The ostectomy gap was either filled with PRP or left empty as a control. The radiographic and densitometric studies were performed after surgery, then at intervals until 60 days during the post-surgery period. Histological and immunohistochemical evaluations were performed at seven or 60 days post-surgery. Analyses were performed using a statistical analysis system, and the level of significance was set at p <0.05. Results: The median radiographic healing score in the PRP group increased significantly between day 0 and day 60. Furthermore, at 60 days, the median healing score and the proportion of healed ostectomies in the control group (score 1; 1/6 healed) and the PRP group (score 5; 4/5 healed) were significantly different. There were differences between groups in radiographic and densitometric values at days 45 and 60. The histological evaluation showed advanced bone healing at 60 days in the PRP group and signs of delayed union in the control group. Clinical relevance: Platelet-rich plasma can be used as an adjuvant therapy because it may promote better bone healing of a radial ostectomy treated with external skeletal fixation in dogs.

A standartized research protocol for platelet-rich plasma (PRP) preparation in rats

Introduction: The urgent need for studies using standardized protocols to evaluate the real biological effects of PRP has been emphasized by several authors. Objective: The purpose of this study was to standardize a methodology for autologous Platelet-Rich Plasma (PRP) preparation in rats. Material and methods: Twentyfour, 5 to 6-month-old, male rats, weighing 450 to 500 g were used. After general anesthesia, 3.15 ml of blood was collected from each animal, via cannulation of the jugular vein. A standardized technique of double centrifugation was used to prepare PRP. PRP samples and peripheral blood platelets were then manually counted using a Neubauer chamber. Student’s t-test was used to compare the differences between the number of platelets in peripheral blood and PRP samples (p < 0.05). In addition, PRP and peripheral blood smears were stained to see platelets’ morphology. Results: All surgical procedures were well tolerated by the animals and they were healthy during the entire experimental period. PRP samples showed higher significantly platelet concentrations than peripheral blood samples (2,677,583 and 683,680 respectively). Conclusion: Within the limits of this study, it can be concluded that the method used produced autologous PRP with appropriated platelet quantity and quality, in rats.