The effect of low-level laser irradiation (Ga-Al-AsP - 660nm) on in vitro and in vivo melanoma
It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation.
Methods: We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation.
The in vivo mouse model (male Balb C, n=21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660nm 50mW CW laser, beam spot size 2mm2, irradiance 2.5W/cm2 and irradiation times of 60s (dose 150J/cm2) and 420s (dose 1050J/cm2) respectively.
Results: There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48+/-1.40% and 4.26+/-0.60%) at 72h post-irradiation.
This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150J/cm2 dose group were not significantly different from controls. For the 1050J/cm2 dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups.
Conclusions: LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5W/cm2) and high dose (1050J/cm2) significantly increases melanoma tumor growth in vivo.
Author: Lucio FrigoJuliana LuppiGiovani FaveroDurvanei MariaSocrates PennaJan BjordalRene BensadounRodrigo Alvaro Lopes Martins
Credits/Source: BMC Cancer 2009, 9:404
Published on: 2009-11-20
Copyright by the authors listed above - made available via BioMedCentral (Open Access). Please
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