Banca de DEFESA: Mylene Martins Monteiro

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Mylene Martins Monteiro
DATE: 03/03/2023
TIME: 14:30
LOCAL: Plataforma Teams
TITLE:

Effects of photobiomodulation therapy on wound repair in oral mucositis model: in vitro study

KEY WORDS:

Oral mucositis; In vitro model; Proinflammatory cytokines; Low level laser; Photobiomodulation.

PAGES: 100
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUMMARY:

Oral mucositis (OM), considered the main adverse effect of radio-induced treatment in head and neck cancer. The Multinational Association for Supportive care in Cancer/International Society for Oral Oncology (MASCC/ISOO) guidelines recommends photobiomodulation therapy (PBMT) in the mucositis prevention and treatment of patients undergoing head and neck radiotherapy, associated or not with chemotherapy. The PBMT has proven to increase wound healing and reduce inflammation and pain. However, despite recommended, the effects of the PBMT in cellular level is still being described. All things considered, to better understand the effects of low-level laser in prevention and treatment of oral mucositis, the aim of this study was to analyze the effects of different parameters of PBMT on migration, proliferation and gene expression using an in vitro oral mucositis model treated with three stimuli: ionizing radiation, lipopolysaccharide (LPS) of Escherichia coli and total extract of the bacterium Porphyromonas gingivalis (Pg). This work was divided in 2 studies, presented in manuscript format. The first one aimed to analyzed cell viability effects by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, of different laser power in a cultured cell line of human gingival fibroblasts, after oral mucositis model stimuli. The PBMT was delivered in four sessions with 6h interval. It was shown that regarding wavelength of 660 nm, after 24 h from the last laser irradiation session, the groups outputted in 30 mW of power maintained the cell viability while operating with 2, 4, and 5 J/cm2. The groups treated with a higher power (40 mW), cell viability was reduced using 2, 3, and 5 J/cm2 doses, with statistical significance for 5 J/cm2 (p < 0.001). Delivering 2, 4, and 5 J/ cm of density of energy with 30 mW and more time of exposure presented better results on cell viability compared to the same density of energy with output power of 40 mW. The second study analyzed the power of 30mW with different energy densities in gene expression by RT-qPCR, wound closure by scratch assay, morphology and α-SMA expression by immunofluorescence. Assays were performed 24h after oral mucositis stimuli. Fibroblasts treated with densities of energy of 3 and 4 J/сm2, and keratinocytes with 5 J/сm2 showed better response in proliferation and migration. Densities of 3 and 5 J/сm2 have presented a significant increase in the expression of PI3K/AKT/mTOR pathway genes in keratinocytes. In fibroblasts, the expression tended to enhance when 2 J/сm2 was applied. For the inflammatory cytokines (TNF-α, IL1β, IL6 and NFκB), although PBMT showed a modulation tendency in both cell lines, only IL1β was significantly increased in keratinocytes. The greater expression of α-SMA was observed when 3 J/сm2 were selected. In conclusion, the present study showed that delivering 660 nm, 30 mW were efficient stimulating cell migration, proliferation and accelerating wound healing. It is considered a promising therapy since PBMT can modulate pathways involving in wound repair. However, different energy densities presented distinct responses, understanding the effect of each laser parameter is fundamental to improve treatment strategies.

BANKING MEMBERS:
Externa à Instituição - CAMILA DE BARROS GALLO - USP
Presidente - 1278451 - ELIETE NEVES DA SILVA GUERRA
Externo à Instituição - GABRIEL ALVARES BORGES
Externa à Instituição - TAIA MARIA BERTO REZENDE - UnB