Exploring the effects of low-level laser therapy on fibroblasts and tumor cells following gamma radiation exposure.
Ionizing radiation (IR) induces DNA damage and low-level laser therapy (LLLT) has been investigated to prevent or repair detrimental outcomes resulting from IR exposure. Few in vitro studies, however, explore the biological mechanisms underlying those LLLT benefits. Thus, in this work, fibroblasts and tumor cells are submitted to IR with doses of 2.5 Gy and 10 Gy. After twenty-four-h, the cells are exposed to LLLT with fluences of 30 J cm-2, 90 J cm-2, and 150 J cm-2. Cellular viability, cell cycle phases, cell proliferation index and senescence are evaluated on days 1 and 4 after LLLT irradiation. For fibroblasts, LLLT promotes - in a fluence-dependent manner - increments in cell viability and proliferation, while a reduction in the senescence was observed. Regarding tumor cells, no influences of LLLT on cell viability are noticed. Whereas LLLT enhances cell populations in S and G2/M cell cycle phases for both cellular lines, a decrease in proliferation and increase in senescence was verified only for tumor cells. Putting together, the results suggest that fibroblasts and tumor cells present different responses to LLLT following exposure to gamma-radiation, and these promising results should stimulate further investigations. Senescence of tumor cells and fibroblasts on the 4thday after ionizing radiation (IR) and low-level laser therapy (LLLT) exposures. The number of senescent cells increased significantly for tumor cells (a) while for fibroblasts no increment was observed (b). The blue collor indicates senescence activity.
Nuclear Technology Postgraduate Program, University of Sao Paulo, Av. Prof. Lineu Prestes, 2242, 05508-000, São Paulo, Brazil.|Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Camila
C
Ramos Silva
Nuclear Technology Postgraduate Program, University of Sao Paulo, Av. Prof. Lineu Prestes, 2242, 05508-000, São Paulo, Brazil.|Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Fernanda Viana
FV
Cabral
Nuclear Technology Postgraduate Program, University of Sao Paulo, Av. Prof. Lineu Prestes, 2242, 05508-000, São Paulo, Brazil.|Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Claudinei Francisco Morais
CF
de Camargo
Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Silvia Cristina
SC
Núñez
Nuclear Technology Postgraduate Program, University of Sao Paulo, Av. Prof. Lineu Prestes, 2242, 05508-000, São Paulo, Brazil.|Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Tania
T
Mateus Yoshimura
Biochemistry and Biophysical Laboratory, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, 05503-900, Brazil.|Medical School, University of Sao Paulo, Av. Dr. Arnaldo, 455, 01246-903, São Paulo, Brazil.
Arthur Cássio
AC
de Lima Luna
Biochemistry and Biophysical Laboratory, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, 05503-900, Brazil.|Medical School, University of Sao Paulo, Av. Dr. Arnaldo, 455, 01246-903, São Paulo, Brazil.
Durvanei Augusto
DA
Maria
Laboratory of Optical Therapy (Center for Lasers and Applications/Nuclear and Energy Research Institute), Av. Prof. Lineu Prestes, 2242, 05508-000, Brazil.
Martha Simões
MS
Ribeiro
D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D016922:Cellular Senescence; D005347:Fibroblasts / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D028022:Low-Level Light Therapy; D000069079:Radiation Exposure / Q000009:adverse effects*
breast cancer cells; fibroblasts; ionizing radiation; photobiomodulation; red laser