# Histopathology Findings of Low‐Level Laser Therapy Effectiveness on Achilles Tendon Repair in Rabbit Model

## TL;DR

This study shows that low-level laser therapy improves Achilles tendon healing in rabbits by reducing inflammation and improving collagen structure.

## Contribution

The study demonstrates the effectiveness of 650 and 750 nm LLLT on Achilles tendon repair in a rabbit model.

## Key findings

- LLLT at 650 and 750 nm significantly improved tendon healing compared to the control group.
- Treated groups showed better organized tendon fibers and reduced inflammation and collagen fiber waviness.
- Both wavelengths showed similar results, with no significant differences between them.

## Abstract

Low‐level laser therapy (LLLT) has been utilized to treat tendinitis and various other musculoskeletal conditions. The current study assessed the impact of LLLT (650 and 750 nm) on tendon repair in rabbits.

Fifteen 2‐year‐old male New Zealand White rabbits were divided into three groups: control, 650 nm laser and 750 nm laser therapy. After applying Achilles tendon‐destructive surgery on their right legs, rabbits underwent LLLT, and tendon repair was assessed using histopathology and immunohistochemistry (IHC) findings. All data were analysed using SPSS version 21, considering a significant level <0.05.

The study's histopathological and immunohistochemical analysis revealed that LLLT at 650 and 750 nm significantly improved tendon healing compared to the control group (p < 0.05). The treated groups exhibited better organized tendon fibres with reduced discontinuity, collagen fibre waviness, and inflammatory response (p < 0.05). Both laser wavelengths showed similar results with no significant differences between them (p > 0.05), but both were notably better than the control group in reducing inflammation, enhancing fibre structure, and lowering levels of collagen type I (Col‐I); collagen type III (Col‐III); transformer growth factor beta (TGF‐β); galectin‐3 (galectin‐3); VGF nerve growth factor inducible; vascular endothelial growth factor (VEGF), indicating a more effective healing process with LLLT.

Due to our findings, LLLT at 650 and 750 nm effectively reduced inflammation, improved structural integrity, and enhanced the organization of collagen fibres for Achilles tendon repair in rabbits.