Efeitos embriotóxicos e teratogênicos da LLLT : estudo em zebrafish

Abstract

The low-level laser therapy (LLLT) has been widely used in Dentistry, considering its local and systemic effects as well as its therapeutic and biomodulatory action on the tissues. Therefore, the aim of this study was to evaluate the embryotoxicity, teratogenesis and systemic alteration caused by LLLT, using a diode laser (GaAlAs) with infrared (ʎ830nm, 90mW, CW) and red (ʎ685nm, 30mW, CW) wavelengths, in the initial development of the Zebrafish embryos. For this, 1560 embryos, monitored from fecundation to 5 dpf, were used and the eclosion, embryotoxicity, and survival rates, were measured. The analysis of the heartbeat, exploratory and aversive behavior, calcein and alcian blue techniques were realized only in the end of the experiment, with 5 dpf. The animals were divided in three groups. One control group (Ctrl) with 140 animals without LLLT, and two experimental groups, with 710 animals each, irradiated with infrared laser (IR) or red laser (R). The experimental groups were subdivided in five subgroups according to the energy densities of energy received (0.5J, 1.0J, 2.0J, 4.0J, 8.0J) with 142 animals in each subgroups. The LLLT was performed in the first, second and fifth dpf, according to the stipulated parameters. The results obtained in the present study showed that in groups with LLLT, there was a delay in the eclosion, a higher mortality rate and the presence of teratogenic Changes in the animals, as well as behavioral alterations, when compared to control group. The heartbeat was higher in both IR and R groups, when compared to the control group, with the IR group sowing the highest values. The cartilage and bone formation didn’t show any visually alterations, keeping the normality standards.