Promoted Viability and Differentiated Phenotype of Cultured Chondrocytes With Low Level Laser Irradiation Potentiate Efficacious Cells for Therapeutics

Abstract

Effective clinical treatments of cartilage lesions in affected joints require large numbers of viable chondrogenic cells generated through in vivo stimulation or ex vivo expansion of chondrocytes isolated from small biopsy specimens. Conventional passaging of chondrocytes in culture provides sufficient cells for treatments but these cells usually lose their differentiated phenotype. This leads to the formation of fibrocartilaginous tissue due to a malfunctioning repair process. Biostimulation of passaging chondrocytes with low level laser irradiation (LLLI) may theoretically produce more functional chondrocytes for cell-based repair of cartilage defects. Molecular and cellular analyses, cytochemistry, cell cultivation, and microscopy showed that LLLI treatments were found to (1) increase chondrocyte viability, (2) promote secretion of matrix proteins, (3) upregulate expression of chondrogenic genes, and (4) downregulate gene expression of cell destructive proteases and genes coding for mediators involved in the extrinsic apoptosis signaling pathway. Furthermore, LLLI attenuated induction of genes associated with cell death and matrix breakdown induced by IL-1β, some of which was seen at the protein level, with verification of effects on gene expression in the C28/I2 human chondrocyte line. LLLI treatments during culture generated larger numbers of viable chondrocytes compared to untreated cultures. Moreover, LLLI-treated chondrocytes in culture also rectified and simultaneously maintained their differentiated phenotype. Cultured chondrocytes treated with LLLI are a promising cell source for repairing cartilage lesions in vivo and restoration of articular function using tissue engineering strategies.

In Vitro and In Vivo Effects of Light Therapy on Cartilage Regeneration for Knee Osteoarthritis: A Systematic Review

“…1 . From the initial 1049 records, identified 33 studies (3 in vitro 18 -20 and 30 in vivo 7 -9,21 -47 ) met the eligibility criteria and were included in this systematic review.…”

“…The judgment of risk of bias for each in vitro study and a summary for each domain is displayed in Figure 2a . The “Selection of Cells” domain presented unclear risk of bias in 2 in vitro studies 19,20 that did not report the animal characteristics from which the cartilage samples were obtained. The “Confounding Variables” domain was judged as low risk of bias for all in vitro studies.…”

“…The “Confounding Variables” domain was judged as low risk of bias for all in vitro studies. Although, the culture medium volume was not provided in 2 studies 19,20 and the influence of the culture medium volume in varying levels of irradiation could not be assessed. The “Planning and Implementation of Interventions,” “Exposure of Measurement,” and “Blinding Outcome Assessment” domains were judged as high risk of bias due to an inadequate measurement of semiquantitative or qualitative outcomes.…”

“…The chondrocyte proliferation and viability measured by MTS 19 [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and XTT 20 [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assays were increased after LT, which were time and dosage dependent.…”

“…At the ECM, the matrix proteins collagen type II (COL II) and aggrecan (ACAN) expressions were increased after LT treatment measured by polymerase chain reaction (PCR 19 ) and immunocytochemistry. 20 One study 19 reported no significant differences in glycosaminoglycans (GAGs) stained by Alcian blue during the treatment duration but revealed a significant difference at the posttreatment follow-up (until day 12 posttreatment). The same study 19 reported a downregulation of collagen type I (COL I) and an increase in transcription factor SOX-9 expression (measured by PCR and Western blot).…”