Concentrado autólogo de plaquetas na osteoartrose induzida em coelhos: avaliações artroscópica, macroscópica, histológica e imuno-histoquímica da articulação fêmero-tíbio-patelar

Abstract

This study aimed to evaluate the effect of autologous platelet concentrate (APC) on osteoarthritis (OA) experimentally induced in rabbits, through histological, immunohistochemical and arthroscopic evaluation, and simultaneously determine plasma concentrations of the transforming growth factor β1 (TGF -β1) and platelet-derived growth factor (PDGF). The study used 30 male rabbits, young, healthy, New Zealand breed, with an average body mass of 3.0 kg, and submitted to rupture of the cranial cruciate ligament (CrCL) (M1) by video arthroscopy to induce OA. At 21 days after the rupture, the rabbits were submitted to ligament replacement (M2) by video arthroscopy and were divided into two groups according to the treatment: The control group, which received 0.5 ml of the Ringer Lactate solution by intra-articular injections and the CAP group, which received 0.5 ml of autologous platelet concentrate by intra-articular injections. The intra-articular injections of the treatments were performed immediately after the ligament replacement, at 15 and 30 days after the replacement. Five rabbits from each group were euthanized at 15 days after replacement (M3), another five at 30 (M4), and the remaining five rabbits from each group at 60 days (M5) after replacement. At those same moments, arthroscopic evaluations were carried out to assess the evolution of the degenerative process and the response to the treatments applied and before each procedure, two ml of blood from the central auricular artery were collected and deposited in tubes containing EDTA and later stored in sterile eppendorfs in two equal aliquots to measure TGF-β1 and PDGF respectively. In M3, M4 and M5, after euthanasia of the animals, fragments of the synovial capsule and articular cartilage were collected for histological and immunohistochemical evaluation. It was observed in the histological evaluation that the animals that received the CAP had significantly (p <0.05) less synovial inflammation, less cell proliferation and less degradation of the extracellular matrix (ECM) when compared to the rabbits that received Ringer Lactate. In the immunohistochemical evaluation, the animals that received the CAP showed lower secretion (p <0.05) of interleukin 1 (IL-1β), tumor necrosis factor (TNFα), morphogenetic protein 2 (BMP-2) and greater secretion of PDGF in the synovial membrane when compared to the rabbits that received Ringer Lactate, and in the cartilage of the animals of that same group, significantly lower (p <0.05) IL-1β and TNFα secretion and greater BMP-2 synthesis and secretion and PDGF when compared to animals in the control group. In the arthroscopic evaluation, a significant improvement (p <0.05) in inflammation of the synovial membrane, less formation of fibrous cords and less fibrillation of the cartilage was observed in the animals that received CAP. Finally, when assessing the concentration of growth factors, there were no statistically significant differences (p> 0.05) in TGF-β1 concentrations in any of the moments evaluated after CAP applications, and a statistically significant difference in plasma concentration was observed of PDGF in M5 in CAP group animals when compared to control group animals. According to the results of this experiment, it is concluded that the CAP is able to control the inflammatory process that occurs during OA, improving the synovitis present in the synovial capsule while decreasing the degradation of the articular cartilage. Additionally, this biological compound regulates the synthesis and secretion of inflammatory cytokines and increases the release of PDGF.