A Histologic Assessment of the Influence of Low-Intensity Laser Therapy on Wound Healing in Steroid-Treated Animals

Abstract

Objective:The aim of the present study was to evaluate the effect of low-intensity laser therapy on the wound healing process treated with steroid. Background Data: Various biological effects have been associated with low-level laser therapy (LLLT). Materials and Methods: Forty-eight rats were used, and after execution of a wound on the dorsal region of each animal, they were divided into 4 groups (n = 12), receiving the following treatments: G1 (control), wounds and animals received no treatment; G2, wounds were treated with LLLT; G3, animals received an intraperitoneal injection of steroid dosage (2 mg/kg of body weight); G4, animals received steroid and wounds were treated with LLLT. The laser emission device used was a GaAIAs (904 nm), in a contact mode, with 2.75 mW gated with 2.900 Hz during 120 sec (33 J/cm 2 ). After the period of 3, 7, and 14 days, the animals were sacrificed and the parts sent to histological processing and dyed using hematoxylin and eosin (HE) and Masson trichromium (MT) techniques. Results: The results have shown that the wounds treated with steroid had a delay in healing, while LLLT accelerated the wound healing process. Also, wounds treated with laser in the animals treated with steroid presented a differentiated healing process with a larger collagen deposition and also a decrease in both the inflamatory infiltrated and the delay on the wound healing process. Conclusion: LLLT accelerated healing, caused by the steroid, acting as a biostimulative coadjutant agent, balancing the undesirable effects of cortisone on the tissue healing process. 199

Effects of He-Ne laser irradiation on chronic atrophic gastritis in rats

“…He-Ne laser, its characteristics such as 632.8 nm of wavelength, good directivity , high intensity, good monochromaticity, is a low-level laser [11][12][13][14] . The low-level laser has some biology effects such as cell vitality [15][16][17][18] , phagocytosis [19][20][21] , immune responses [22][23][24][25] , but as far as its usage for the treatment of digestive disease, there were only few reports [26][27][28] . On one hand, there was no difference between treating gastric ulcer through bark and by endoscope [29] .…”

Uso combinado da laserterapia de baixa potência e da inibição da ciclooxigenase-2 na reepitelização de ferida incisional em pele de camundongos: um estudo pré-clínico

“…Samples of all skin lesions were collected in a way that included part of the skin adjacent to the sutured edges of the incisional wound and all the scar tissue in depth. 2,12,20 The samples of the skin lesions obtained were fixed in paraformaldehyde-10% (p H 7.0) for at least 24 hours. After fixation, the samples were gradually dehydrated in increasing concentrations of ethanol (70% to 100%), cleared in xylene, and embedded in paraffin in accordance with routine histological methods.…”

“…Low level laser therapy (LLLT) has been mainly and widely used in many biomedical areas in order to modulate inflammatory response and accelerate the tissue repair process. 1,2,[11][12][13][14] Recent investigations show the influence of LLLT in the dynamics of healing of the skin and other tissues; however, there are still some controversies about it because of the wide variability and divergence in irradiation parameters, in addition to discrepancies in the biological findings. [14][15][16] Previous studies in our laboratory as well as others have suggested that photo-stimulation by laser seems to occur during the inflammatory and proliferative phases of wound healing, exactly because of their influence on biomodulation of eicosanoids, especially PGs, and on the oxidative enzyme system of the skin.…”

“…[14][15][16] Previous studies in our laboratory as well as others have suggested that photo-stimulation by laser seems to occur during the inflammatory and proliferative phases of wound healing, exactly because of their influence on biomodulation of eicosanoids, especially PGs, and on the oxidative enzyme system of the skin. 1,2,5,[11][12][13][14][15][16][17][18][19] Consequently, studies that show the effects of combined treatments in wound healing are opportune, since both laser therapy and the use of COX inhibitors act during the same time period in the repair process, that is, both separate treatments affect the inflammatory and proliferative phases of skin healing in animals and humans. Considering this scenario, the purpose of this pre-clinical study was to evaluate the isolated and combined effects of low level laser therapy (LLLT) with helium-neon (He-Ne, 632nm) and selective inhibition of cyclooxygenase-2 (COX-2) in the reepithelialization of skin-incisional wounds in mice.…”

Influence of local or systemic corticosteroids on skin wound healing resistance

“…According to previous studies 3,14 , corticotherapy used in animals participates in a complex metabolic process that results in malnutrition. Even though no satisfactory explanation has been found for this phenomenon, this worsening of the animal general condition may have contributed to delay wound healing.…”