Analysis of experimental tendinitis in rats treated with laser and platelet-rich plasma therapies by Raman spectroscopy and histometry

Abstract

The objective of this controlled experimental study was to analyze the changes in the Achilles tendons of rats with experimentally induced tendinitis after treatment with platelet-rich plasma (PRP) and/or laser therapies by histometry to quantify fibroblasts and by Raman spectroscopy to determine the biochemical concentration of collagen types I and III. Fifty-four male Wistar rats were divided into six treatment groups: control (G1); PRP only (G2); irradiation with 660 nm laser (G3); irradiation with 830 nm laser (G4); PRP plus 660 nm laser irradiation (G5); and PRP plus 830 nm laser irradiation (G6). Injuries (partial tenotomy) were inflicted in the middle third of the Achilles tendon, with PRP added prior to suture in the appropriate experimental groups. A diode laser (model Laser Flash® III, DMC Equipamentos Ltda, São Carlos, SP, Brazil) that can be operated in two wavelengths 660 and 830 nm was used for irradiation treatments. The irradiation protocol was energy density of 70 J/cm², 20 s irradiation time, and 0.028 cm² spot area, per point in three points in the injured. The histometry was made in micrographical images of the H&E stained sections and evaluated by ImageJ (version 1.46r)®. Raman spectra were collected using a dispersive spectrometer at 830 nm excitation, 200 mW power, and 10 s integration time (P-1 Raman system, Lambda Solutions, Inc. MA, USA). The relative amount of type I collagen was significantly greater in the PRP plus 830 nm laser irradiation group (468 ± 188) than in the control (147 ± 137), 630 nm laser only (191 ± 117), and 830 nm laser only (196 ± 106) groups (p < 0.01), while the quantity of type III collagen was significantly greater in the PRP-only group compared to both irradiated groups without PRP (p < 0.05). Treatment with PRP combined with irradiation at 830 nm resulted in a larger number of fibroblasts and increased concentration of type I collagen, thus accelerating the healing of the injured tendon.

The effects of orthobiologics in the treatment of tendon pathologies: a systematic review of preclinical evidence

“…Overall, when applied to tendon ruptures, blood‐derived products induce an acceleration of the initial phases of tendon healing with reduced inflammation and improved cell proliferation/neovascularization, while these parameters tend to be similar between experimental and control groups at the final follow up [47, 65, 76, 117]. Seven studies concerning collagenase‐induced tendinopathy showed improvements in terms of fibers organization [17, 26, 45, 119], fibers dimension and neovascularization [26], overall histological appearance [20, 45, 119], while one study did not identify any effect of PRP treatment compared to platelet‐derived growth factor‐BB or steroids [100]. Increased cellularity was observed early after treatment in one study [17].…”

Platelet‐rich plasma injections as a treatment for Achilles tendinopathy and plantar fasciitis in athletes

“…27 These growth factors promote the growth of type III collagen, the predominant form of collagen found during the initial reparative phase of tendon healing, as well as type I collagen that is found predominantly in mature tendon. 82,83 Leukocytes in PRP facilitate tissue repair by clearing damaged tissue and releasing growth factors. 84 PRP has been shown to increase anabolic gene expression in tendons and ligaments.…”

“…They also release a variety of growth factors including platelet‐derived growth factor, transforming‐growth factor beta, and vascular endothelial growth factor that stimulate cell proliferation and angiogenesis 27 . These growth factors promote the growth of type III collagen, the predominant form of collagen found during the initial reparative phase of tendon healing, as well as type I collagen that is found predominantly in mature tendon 82,83 . Leukocytes in PRP facilitate tissue repair by clearing damaged tissue and releasing growth factors 84 .…”

Raman Spectroscopy in Skeletal Tissue Disorders and Tissue Engineering: Present and Prospective

“…69 In equine tendons, age-related changes in post-translational glycation of collagen were detected and likely correlated to decline in function. 70 RS application has been described useful in the studies regarding experimental tendinitis, 71 tendon injuries, 72 or degenerative lesions of the supraspinatus RCT. 73 In the combined magnetic field, some studies dealt with periodontal ligament changes during orthodontic treatments 74,75 or in mandibular reconstruction.…”

“…RS application has been described useful in the studies regarding experimental tendinitis, 70 tendon injuries, 71 or degenerative lesions of the supraspinatus RCT. 72 In the combined magnetic field, some studies dealt with periodontal ligament changes during orthodontic treatments 73 , 74 or in mandibular reconstruction.…”