## 2 Results and Discussion
### Discussion
Furthermore, the beneficial effect achieved with both therapies was reflected in data provided byowners in the treatment satisfaction questionnaires, where both treatments achieved a high degree of satisfaction from the first month post-treatment and maintained until the end of the study. OA is a degenerative disease that can affect all articular structures, causing joint degeneration with osteophyte formation, bone remodeling and alteration of periarticular tissues including the synovial fluid, joint capsule, subchondral bone, muscle, tendon and ligaments [58]. Among the methods of evaluation of this pathology, radiology is used as a simple technique for its availability and accessibility [59], although there is controversy as to its utility as a diagnostic method for the response to different treatments. It has been reported that OA in rabbits treated with mesenchymal cells derived from adipose tissue showed radiographic changes at 20 weeks post infiltration [60]. Contrary to a previous study [60], here, improvement in the signs of OA was not seen, however a progression of the signs was not seen either during the six month study, similar to those results observed in human [61] and veterinary studies where [PERSON] _et al._ reported no significant differences in the radiographic exam between animals treated with PRP and control group after cranial cruciate ligament surgery [62]. The radiological analysis used in this study was inconclusive. One reason to explain these findings could be related to technical limitations for detecting and evaluating the progression of osteoarthritis in both groups, although radiographs were evaluated and scored in a multiple blind fashion. These results do not necessarily mean that changes did not exist at a cartilage structure level, but in order to demonstrate this, a magnetic resonance imaging (MRI) study should have been conducted to evaluate these structures in more detail or biopsies of the cartilage in affected joints should have been performed [63]. These complementary assessments were not performed due to the complications they implied for the owners. The ROM in joints affected by OA decreases significantly [8, 57], producing a decrease in functionality that has a detrimental effect on the ability to lead a normal life [1]. It has been observed that treatments with aMSCs [8, 22] and PRGF [5, 10, 32] enhance the functionality of joints affected by OA which leads to an improvement in clinical signs, reducing lameness and providing notable recovery of previously limited walking and running activities [8, 52]. In this study, enhanced joint mobility and functionality were observed in both of the treatment groups, although there is a significantly greater improvement in the aMSCs group at 6 months post treatment. The effect PRGF has in the treatment of OA is due to the behavior of the platelet concentrate, acting as a scaffold which through the various growth factors promotes the stimulation of chondrogenesis, increases hyaluronic acid production, stabilizes angiogenesis and differentiation of the existing cells in the area treated [6, 64]. Platelets are cells that contain many important bioactive proteins and growth factors (GFs) which are polypeptide substances, both soluble and diffusible, that regulate key processes in tissue repair, including cell proliferation, chemotaxis, migration, differentiation, and extracellular matrix synthesis [27, 65, 66]. The results of the current study coincide with those of numerous studies, both _in vitro_ and _in vivo_, that have shown that PRP stimulates chondrocyte proliferation and matrix synthesis [67, 68], and indicate that intra-articular injection of PRP prevents progression of osteoarthritis, improves articular function and reduces pain in the area [10, 48, 69].