Stimulatory effect of 660 nm low level laser energy on hypertrophic scar-derived fibroblasts: possible mechanisms for increase in cell counts.
OBJECTIVE
Varying effects of red light wavelengths on in vitro cells have been reported. Low level lasers (LLL) are employed to assist wound healing especially for indolent ulcers. On healing, burn wounds may become hypertrophic, resulting in excessive wound contraction, poor cosmesis, and functional impairment. This study enquired whether 660 nm LLL affected hypertrophic scar-derived fibroblasts.


METHODS
The experiments investigated the effect of a 660 nm, 17 mW laser diode at dosages of 2.4 J/cm2 and 4 J/cm2 on cell counts of two human fibroblast cell lines, derived from hypertrophic scar tissue (HSF) and normal dermal (NDF) tissue explants, respectively. The protocol avoided transfer of postirradiated cells. Estimation of fibroblasts utilized the methylene blue bioassay.


CONCLUSIONS
The post-660 nm-irradiated HSFs exhibited very significantly higher cell counts than controls P < 0.01 on days 1-4 (Mann-Whitney U-test), and P < 0.01 on days 1-3 for similarly irradiated NDFs.
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong.
C
C
Webb
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M
Dyson
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WH
Lewis
D000328:Adult; D002452:Cell Count; D002460:Cell Line; D017439:Cicatrix, Hypertrophic / Q000532:radiotherapy*; D005260:Female; D005347:Fibroblasts / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D007259:Infrared Rays; D053685:Laser Therapy; D008751:Methylene Blue; D018709:Statistics, Nonparametric
D008751:Methylene Blue