The Effects of Low-Level Laser Therapy, 670 nm, on Epiphyseal Growth in Rats

Abstract

The longitudinal growth of long bones is attributed to epiphyseal growth. However, the effects of low-level laser therapy (LLLT) in such structures has still not been studied extensively in the literature. Therefore, the aim of this study was to evaluate the use of LLLT, 670 nm, at three different doses on the epiphyseal growth of the right tibia of rats. Twenty-one Wistar rats, aged four weeks, were subjected to the application of LLLT, with dosage according to the group (G4: were submitted to the application of 4 J/cm2; G8: were submitted to the application of 8 J/cm2; G16: were submitted to the application of 16 J/cm2). After completion of protocol they were kept until they were 14 weeks of age and then submitted to a radiological examination (evaluation of limb length) and euthanised. The histological analysis of the growth plates (total thickness and hypertrophic and proliferative zones) was then performed. Comparisons were made with the untreated left tibia. No differences were observed in any of the reviews (radiological and histological), when comparing the right sides (treated) to the left (untreated). It was concluded that the treatment with LLLT within the parameters used caused changes neither in areas of the epiphyseal cartilage nor in the final length of limbs.

Effects of Laser Acupuncture on Longitudinal Bone Growth in Adolescent Rats

“…Some findings support that LLLT has the effects to induce chondrogenesis in vitro [28] and to improve cartilage structure in vivo [29, 30], while others prove that LLLT has no [31] or even negative [19] effect on bone growth. These differences require further study.…”

Efficacy and Effectiveness of Physical Agent Modalities in Complex Regional Pain Syndrome Type I: A Scoping Review

“…We found a single case report [25] describing a 10-year-old boy with CRPS-I treated with laser therapy that did not provide any improvement of symptoms. Moreover, it should be underlined that the administration of laser therapy in development stages of life is controversial due to possible negative effects on bone growth plates [41].…”