Efeito do laser de baixa potência em doses crescentes no processo de cicatrização cutânea em ratos
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2019-02-28
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Universidade Federal de Goiás
Resumo
The wound healing is a constant challenge in the animal surgical clinic, requiring
new therapeutic methods for the process to be optimized and performed properly. In this
aspect, the low-level laser therapy has been studied and applied in different species, as an
auxiliary tool in wound healing. However, because it is a therapy with several variables to be
controlled, it is very difficult to establish ideal protocols. Objectives: To evaluate the effects
of using low-level laser therapy in increasing doses or fixed in the healing of cutaneous
wounds in rats. Material and Methods: 75 male rats were used, divided into three groups,
the control group that received no treatment, known as GC, group treated with laser at a
fixed dose of 3 J/cm2
(GLF) and treated with increasing doses 1 J/cm2
, 3 J/cm2
, 5 J/cm2
(GLV).
The lesion was performed with metallic punch 9 mm diameter on the back of each animal
and laser irradiated on alternate days. Macroscopic and histological analyzes were performed
using HE and picrosirius red staining techniques. Results: macroscopically, all groups had
complete closure of the wounds on the 19th day after the lesions. Microscopically it was
observed that on days 3 and 7 after the lesion, the presence of polymorphonuclear was lower
in the irradiated groups and that GLV presented the lowest mean in relation to the other
groups (p <0.05). The mononuclear infiltrate was observed at all times of microscopic
evaluation, being present in greater quantity in the irradiated groups. On the third day of the
lesion, GLV presented a greater amount of this type of cell (p <0.05), on seventh day the
infiltrate was higher in GLV (p <0.05) and, on days 10 and 14, the infiltrate decreased in all
groups, with the highest mean GLF (p <0.05). From the seventh day of injury, vascular
connective tissue was observed. On the 14th day, fibrovascular tissue was observed in the GC
and more frequently for GLV (p <0.05). With the evaluation of angiogenesis, a greater
number of GLF vessels (p ˂ 0.05) were observed on day seven post-injury. On the 21th day of
injury, GC had fewer vessels than the irradiated groups (p ˂ 0.05). Conclusion: The low-level
laser therapy optimized wound healing, attenuated the acute inflammation, increased local
vascularization, provided the formation of more organized and larger granulation tissue
collagen deposition. The energy density of 1 J/cm2 was more efficient in the first three days of
the lesion, with better results in the anti-inflammatory action, whereas 3 J / cm2 showed
better results on the seventh day of injury. Energy densities of 3J/cm2
and 5J/cm2
from the
14th day of injury were shown to be beneficial for tissue remodeling. In this way, this work
contributes to the understanding of the application of different energy densities in relation to
the different periods of the cicatrization process.
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OLIVEIRA, L. P. Efeito do laser de baixa potência em doses crescentes no processo de cicatrização cutânea em ratos. 2019. 53 f. Dissertação (Mestrado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2019.