R.P. Cardenas Sandoval1, J.D. Cucarian Hurtado1, L.D. Bernal Bernal1, S. Cabrera Salazar1, D.M. Gomez Ramirez1, L.M. Gonzalez Ballesteros1, K.M. Hooker Mendoza1, L.N. Ospina Piedrahita1, A.O. Ondo Mendez1, J. Barbosa Santibañez2, L.L. Carvajal Calderón2
1Universidad del Rosario, School of Medicine and Health Sciences, Bogota, Colombia, 2Hospital Universitario Méderi, Orthopaedic Department, Bogota, Colombia

Background: The Anterior Cruciate Ligament (ACL) injury is one of the most prevalent musculoskeletal issues around the world. Low-Level Laser Therapy (LLLT) is a promising therapeutic approach that accelerates the tissue healing process and its reparative properties by biostimulation effects. Fibroblasts are the main cellular resource responsible for this process, despite positive findings that support the use of LLLT to enhance the healing process, in the clinical practice, there is an immense heterogeneity and, there is a lack of evidence that supports which parameters in LLLT are better to enhance the reparative abilities of fibroblasts in ACL impairments.

Purpose: To evaluate the effect of LLLT on the proliferation process in an in vitro culture of isolated fibroblasts from human ACL.

Methods: The units of analysis were the human isolated fibroblasts of the anterior cruciate ligament, obtained from a primary explant to carry out the experimental model. We used a therapeutic laser Chattanooga Intelect® Mobile (850 nm) to irradiate cells for three days each 24 hours. We designed two treatment groups at 1.0 and 5.0 J/cm², and a control group (0 J/cm2). To determine cell proliferation after treatment, we performed a colorimetric analysis. We used the abcam® MTS Assay Kit to detect viable cells 24 hours after exposition to LLLT. We measured the absorbance at 490 nm on the Cytation 3® Cell Imaging Multi-Mode Reader by BioTek instruments, Inc.

Results: In the non-parametric analysis using the Kruskal-Wallis test of proliferation data, we obtained a p-value of 0.089. We concluded that there were no significant differences between the groups in terms of the cell number. Nevertheless, we compared the mean proliferation between groups. The treated Group at 1.0 J/cm2 had a 23% higher cell proliferation than the Control Group, 41% higher compared to treated Group 5.0 J/cm2, and the Control Group had a 19% higher cell proliferation than the treated Group 5.0 J/cm2.

Conclusion(s): The findings of the present study demonstrated that the Low-Level Laser Therapy at 1.0 and 5.0 J/cm2 on ligament fibroblasts generate no significant differences in cell proliferation. However, it is essential to carry out more experiments about cell metabolism and explain the outcomes of metabolic vies to obtain plausible data regarding this variable. We also suggest future work to evaluate other biological functions like migration and expression of extracellular proteins related to the ligament healing process.

Implications: To our knowledge, this is the first study to be performed evaluating the effect of the therapeutic laser on human fibroblasts of the anterior cruciate ligament, which evidences an essential variable for the repair of this ligament, such as proliferation. On the other hand, this investigation reveals data for a later in-vitro and in-vivo experiment by obtaining the respective dose for each stage of repair of this tissue in the clinical field.

Funding, acknowledgements: This work was supported by the Universidad del Rosario (IV-FCS014).

Keywords: Low- level light therapy, fibroblasts, Anterior Cruciate Ligament Injuries

Topic: Research methodology, knowledge translation & implementation science

Did this work require ethics approval? Yes
Institution: Universidad del Rosario
Committee: Universidad del Rosario Ethics Committee
Ethics number: DVO005 649-CV1047

All authors, affiliations and abstracts have been published as submitted.

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