Investigating the Efficacy of Bioactive Sleeves with Embedded Nano-Semiconductors in Alleviating Tendinopathy: An In Vivo Pilot Study

INTRODUCTION Low-level laser therapy (LLLT) utilizes light transmitted at near-infrared wavelengths to induce biochemical changes that promote tissue healing. The Reparel® Sleeve is a Class I Device embedded with nano-semiconductor fibers that mimic LLLT to alleviate joint and tendon pain.The purpose of this study was to determine if bioactive sleeves with nano-semiconductor fibers can objectively affect tendinopathy. METHODS 12 New Zealand white rabbits received 0.2% collagenase injections into the right Achilles tendon. Rabbits were divided into three groups: group I received a sham sleeve (n=4); group II received a Reparel® sleeve I (n=4); and group III received Reparel® sleeve II (n=4). Calf circumference measurements and thermal radiation imaging of the right lower limb were collected on days 7, 14, 21, and 28 post-injection. Two rabbits from each group were sacrificed at 14 and 28 days, and right Achilles tendons were harvested. Histological analysis using Picrosirius red staining was performed to evaluate collagen fiber organization. Immunohistochemical staining was performed to evaluate M1/M2 macrophage activity. # RESULTS A statistically significant difference in calf circumference was found at the 28-day mark between group I versus groups II and III (p < 0.05). Group I displayed an average circumference of 5.2 cm while groups II and III displayed circumferences of 4.9 and 4.6 cm, respectively. A downward trend in pixel density intensity was noted in the thermal radiation imaging for both sleeve groups. Histologic staining showed that group I displayed widespread disorganization and degradation of type I and III collagen fibers, while groups II and III displayed greater organization at the 28-day mark. Immunohistochemical staining revealed greater M1 macrophage activity in group I at the 14-day mark, and greater M2 macrophage activity in groups II and III at the 28-day mark. CONCLUSION The results of our study indicate that application of bioactive nano-semiconductor sleeves had a significant effect in alleviating Achilles tendinopathy, as seen by decreased swelling, temperature, and improved histology.