Amaroli A, Ravera S, Parker S, Panfoli I, Benedicenti A, Benedicenti S
Lasers Med Sci. 2016 May,31(4):741-7. doi: 10.1007/s10103-016-1901-3. Epub 2016
Photobiomodulation is proposed as a non-linear process, and only low-level laser therapy (LLLT) is assumed to stimulate exposed cells, whereas high powered laser and fluences can cause negative effects, exhausting the cell’s energy reserve as a consequence of excessive photon-based stimulation. In our work, we investigated and compared the effects of 808-nm diode laser (CW) with a new flat-top handpiece. To this purpose, we tested the photobiomodulation effects of 1 and 3 J/cm2 fluence, both generated by 100 mW or 1 W of laser power and of 64 J/cm2 of fluence generated by 100 mW, 1 W, 1.5 W or 2 W, as expressed through oxygen consumption and ATP synthesis of Paramecium. Data collected indicates the incremental consumption of oxygen through irradiation with 3 J/cm2-100 mW or 64 J/cm2-1 W correlates with an increase in Paramecium ATP synthesis. The Paramecium respiration was inhibited by fluences 64 J/cm2-100 mW or 64 J/cm2-2 W and was followed by a decrease in the endogenous ATP concentration. The 1 J/cm2-100 mW or 1 W and 3 J/cm2-1 W did not affect mitochondrial activity. The results show that the fluence of 64 J/cm2-1 W more than the 3 J/cm2-100 mW causes greater efficiency in Paramecium mitochondria respiratory chain activity. Our results suggest that thanks to flat-top handpiece we used, high fluences by high-powered laser have to be reconsidered as an effective and non-invasive therapy. Possible associated benefits of deeper tissue penetration would increase treatment effectiveness and reduced irradiation time.
High fluence, Laser irradiation, Laser phototherapy, Low-level laser therapy, Mitochondria, Photobiostimulation