Objective: The aim of this work was to compare the effect of low-level laser therapy (LLLT) on the wound healing process in nondiabetic and diabetic rats. Background Data: Among the clinical symptoms caused by diabetes mellitus, a delay in wound healing is a potential risk for patients. It is suggested that LLLT can improve wound healing. Methods: The tissue used for this study was extracted from animals suffering from diabetes, which was induced by Streptozotocin ® , and from nondiabetic rats. Animals were assembled into two groups of 25 rats each (treated and control) and further subdivided into two groups: diabetic (n = 15) and nondiabetic (n = 10). A full-thickness skin wound was made on the dorsum area, with a round 8-mm holepunch. The treated group was irradiated by a HeNe laser at 632.8 nm, with the following parameters: 15 mW, exposition time of 17 sec, 0.025 cm 2 irradiated area, and energy density of 10 J/cm 2 . Square full-thickness skin samples (18 mm each side, including both injured and noninjured tissues) were obtained at 4, 7, and 15 days after surgery and analyzed by qualitative and quantitative histological methods. Results: Quantitative histopathological analysis confirmed the results of the qualitative analysis through histological microscope slides. When comparing tissue components (inflammatory cells, vessels and fibroblast/area), we found that treated animals had a less intense inflammatory process than controls. Conclusion: Results obtained by both qualitative and quantitative analyses suggested that irradiation of rats with HeNe (632.8 nm), at the tested dose, promoted efficient wound healing in both nondiabetic and diabetic rats as, compared to the control group. 474

Many studies have been conducted on the treatment of burns because they are important in morbidity and mortality. These studies are mainly focused on improving care and quality of life of patients. The aim of this study is the induction of standardized full-thickness burns of the skin of rats using the CO2 laser. The results show that non-contact technique using the CO2 laser is effective to induce such standardization of burning and is an important step in determining the efficiency of different therapies used in treating burns.

Diabetes Mellitus is a condition that results in a delay of the wound healing process, that is associated with an insufficient production of collagen, a decrease of the amount of collagen fibrils and deficient blood flow in the wound area. It is suggested that Low Intensity Laser Therapy acts by improving wound healing in normal organisms, accelerating tissue regeneration. The aim of this work was to investigate the biostimulatory effect of the HeNe laser irradiation, at 632.8 nm, on wound healing in 15 male rats suffering from diabetes induced by Streptozotocin, compared to 15 control diabetic animals. Irradiation parameters were: laser power of 15mW, exposition time of 17 s., irradiated area ofO.025 cm2 and laser energy density of 10 J/cm2. Full-thickness skin squared samples, with 5 mm of non-injured tissue around the wound, were obtained at 4, 7 and 15 days after wounding procedure (5 treated and 5 control animals each time). The histopathologic analysis performed by haematoxylin-eosin staining. Results suggested that the irradiation of diabetic rats was efficient for wound healing. Treated group presented better quality of the wound tissues by the macroscopic observation than control group and the microscopic analysis demonstrated that treated animals had better histopathologic evaluation than non treated.

Many studies have been conducted on the treatment of burns because they are important in morbidity and mortality. These studies are mainly focused on improving care and quality of life of patients. The aim of this study was evaluate the LED phototherapy effects in rats skin full-thickness burns induced by CO laser. The animals were divided in NT group that did not received any treatment and LED group that received LED irradiation at 685 nm, 220 mW, and 4.5 J/cm during 40 s by burned area. Biopsies were obtained after 7, 14, and 21 days of treatment and submitted to histological and immunohistochemical analysis. The LED phototherapy shows anti-inflammatory effects, improves angiogenesis, and stimulates the migration and proliferation of fibroblasts. The T CD8+ lymphocytes were more common in burned areas compared to T CD4+ lymphocytes since statistically significant differences were observed in the LED group compared to the NT group after 7 days of treatment. These results showed that LED phototherapy performs positive influence in full-thickness burns repair from the healing process modulated by cellular immune response. The obtained results allowed inferring that burns exhibit a characteristic cell immune response and this cannot be extrapolated to other wounds such as incision and wounds induced by punch, among others.

Many research works have explored the use of the low power laser as a tool for the control of inflammatory processes. The anti-inflammatory effect of low power optical radiation and its ability to induce analgesia has been reported for different experimental conditions. Many published works are very qualitative in nature. In this work the action of low power laser radiation on acute inflammatory process is evaluated. The time evolution of rat paw edema and pain induced by carrageenan was experimentally monitored. A 632.8 nm He-Ne laser was used for the treatment. The laser treatment, at a dosage of 2,5 J/cm², was applied at the first, second and third hour after the induction of the inflammation. A hydroplethysmometer was used for the evaluation of the inflammation. The measurement of pain sensitivity was performed according to the method described by Randall and Selito, (1957). The laser treatment was capable of inhibiting the carrageenan-induced hyperalgesia by 49% (p<0,001) at the second hour after the induction, as compared to the non-treated group. At the fourth hour (peak of the carrageenan action on hyperalgesia) and at the sixth hour, the achieved inhibition was 49% (p<0,001) and 61% (p<0,001), respectively. In the treated groups, the edema evolution was inhibited by 38% (p<0,01), at the second hour after induction, as compared to the non-treated groups. At the fourth hour (peak of the carrageenan action on leakage) and at sixth hour the achieved inhibition was 35% (p<0,01) and 30% (p<0,05) respectively.