Structural changes of the tendon in experimental tendinopathy and administration of autologous platelet-rich plasma

Abstract

Objectives assessment of structural changes in the calcaneal tendon tissue in experimental tendinopathy under autologous platelet-rich plasma.
 Material and methods. Twenty mature Wistar rats, selected for the study, were divided into 5 groups. Rats of all groups received intra- and peritendinous injections of 0.5 ml of 10% sterile talc suspension to provide the experimental modeling of tendinopathy of the calcaneal tendon. Then the tendinopathy area was treated by injections of autologous platelet-rich plasma (PRP), a hyaluronic acid preparation "Rusvisk" (Rusvisk, Russia) and their sequential combination. The results were evaluated after 10 weeks in the autopsy preparations using a light microscopy method and morphometry.
 Results. The histological signs characteristic of tendinopathy were revealed, such as the disorganization of collagen structures, mucoid and lipoid degeneration, neovascularization, lymphoid and histiocytic infiltration. The injection of PRP, hyaluronic acid, or their sequential combination in the area of simulated tendinopathy led to changes in the histological presentation of the tissue. As a result, the collagen matrix had less signs of disorganization and less pronounced degenerative changes, as well as manifestations of the inflammatory process in the peritenon and the soft tissues surrounding the tendon, in comparison with the histological profile, which was observed in micropreparations in animals with tendinopathy who had no treatment.
 Conclusion. The introduction of PRP into the area of the calcaneal tendon has reduced the manifestations of the inflammatory process, disorganization of the collagen matrix, promoted the enhancement of collagen synthesis by cells and, ultimately, the processes of tissue remodeling.