Efeitos da fotobiomodulação sobre queratinócitos cultivados in vitro: uma revisão sistemática da literatura

Abstract

Photobiomodulation effects on keratinocytes cultured in vitro: a systematic review Photobiomodulation therapy (PBMT) consists of the use of light at low power densities aiming to promote beneficial effects to the body. It has been widely used in medicine, physiotherapy and dentistry to promote relief of pain, wound healing and tissue repair. The literature that aims to evaluate the effects of PBMT in vivo and in vitro consists of several studies that seek to elucidate the cellular and molecular mechanisms involved in this therapy. Although the relevant literature is vast, such mechanisms have not yet been fully elucidated. In addition, there is a lack of systematic reviews summarizing the main results found by these studies, in order to provide evidence of what could already be considered as consensus and aspects that still have knowledge gaps. Thus, this work proposed a systematic review of the literature on the effects of PBMT, using LASER / LED operating in blue, red or near infrared light, on viability, proliferation, migration, expression of cytokines, growth factors and NF-kB of keratinocytes cultured in vitro according to the energy density. A systematic search was performed in the main electronic databases - PubMed, Web of Science, Scopus and LILACS, with no restriction on language and year of publication. 3221 references on the subject were rescued, 1997 had their titles and summaries read, 137 were read in full and 55 were included in the review. Data extracted included author and year of publication, parameters of the light devices used, treatments applied to cells, viability, proliferation, migration and expression of inflammatory markers assays. The primary studies were grouped according to the light spectrum and the results obtained according to the energy densities used, subdivided in 0.1 to 5.0; 5.1 to 10.0; 10.1 to 15.0 and above 15.0 J/cm2. Studies that used more than one spectrum or more than one energy dose were allocated to more than one group. The results demonstrated that photobiomodulatory effects were achieved in the range of 0.1 to 5.0 J/cm2, especially when red and near infrared were used. Doses above 10.0 J/cm2 tended to cause cell death or did not generate changes in the cells in culture. However, in all the bands evaluated and independently of the wavelength used, there was no significant difference between the irradiated and non-irradiated cells regarding the analyzed outcome. Most of the studies did not adequately provide the parameters of the light devices and there was great variability in the energy doses employed. In addition, the heterogeneity of experimental designs and data made it impossible to perform a meta-analysis. The present review may help in the conduction of laboratory studies with more rigorous experimental protocols, use of more adequate energy doses and in the standardization of future experimental designs. Keywords: Phototerapy. Keratinocyte. Dosimetry. Wound healing.