Comparison of low-level laser and dimethyl sulfoxide applications for the treatment oftendon injury in rabbits

Abstract

The aim of this study was to investigate and compare the effects of low-level laser therapy (LLLT) and dimethyl sulfoxide (DMSO) on tendon healing in rabbits. A total of 30 adult healthy New Zealand rabbits were used for this study. The rabbits were randomly allocated into 3 groups containing an equal animal number. The experimental tenotomy of the Achilles tendons was created on longitudinal aspect with 10 mm in length. During the postoperative 21-day of period, rabbits in Group I were exposed to laser beam at a rate of 10.8 J/cm$^{2}$ in 5 cm$^{2}$ area for 4 min. In the same period, 30% DMSO solution was applied externally to the injured tendon region for Group II. Saline solution was applied to the injured tendons area for Group III. Daily clinical examinations of each rabbit were recorded during the treatment period. At the end of the 21-day treatment period, all rabbits were euthanized and their tendons were examined macroscopically. Histopathological examination of the tendons was then carried out. Immature and mature connective tissue cells had an equal number of distribution in Group I; mild immature connective tissue cells and mostly mature connective tissue cells were observed in Group II, and partially longitudinal, scattered, and irregularly arranged, immature connective tissue cells (fibroblasts) were observed in Group III. As a result, satisfactory findings were obtained from LLLT and DMSO applications for the treatment of tendon injuries taking into consideration the histopathological and clinical findings. Moreover, DMSO provided a better recovery when these two applications were compared. However, it was suggested that combined application of DMSO and LLLT might have a strong positive effect on the healing process.