Effects of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing.

Gallium-arsenide (GaAs) and helium-neon (HeNe) lasers are the most commonly used low-energy lasers in physiotherapy for promoting wound healing and pain modulation. The aim of this study was investigate the effect of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing. The animals were randomly divided into five groups (n=6): Controls (skin injured animals without local or systemic treatment), skin injury treated with HeNe 1 J/cm(2) (two seg); skin injury treated with HeNe 3 J/cm(2) (six seg); skin injury treated with GaAs 1 J/cm(2) (three seg); skin injury treated with GaAs 3 J/cm(2) (nine seg). A single circular wound measuring 8 mm in diameter was surgically created on the back of the animal. The rats were irradiated at 2, 12, 24, 48, 72, 96, and 120 h after skin injury. The parameters, namely hydroxyproline content, activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and lipid (TBARS) and protein oxidation (carbonyl groups) measurements were assessed. In addition, wound size regression was also analyzed. The results showed an improvement in the wound healing reflected by the reduction in wound size and increased collagen synthesis. Moreover, a significant reduction in TBARS levels, carbonyl content, and SOD and CAT activities were observed after laser irradiation, particularly with the treatments HeNe laser 1 and 3 J/cm(2) dose and GaAs 3 J/cm(2) dose. The data strongly indicate that LPLI therapy is efficient in accelerating the skin wound healing process after wounding, probably by reducing the inflammatory phase and inducing collagen synthesis.

Genotoxic evaluation of Mikania laevigata extract on DNA damage caused by acute coal dust exposure.

In the present article, we report data on the possible antigenotoxic activity of Mikania laevigata extract (MLE) after acute intratracheal instillation of coal dust using the comet assay in peripheral blood, bone marrow, and liver cells and the micronucleus test in peripheral blood of Wistar rats. The animals were pretreated for 2 weeks with saline solution (groups 1 and 2) or MLE (100 mg/kg) (groups 3 and 4). On day 15, the animals were anesthetized with ketamine (80 mg/kg) and xylazine (20 mg/kg), and gross mineral coal dust (3 mg/0.3 mL saline) (groups 2 and 4) or saline solution (0.3 mL) (groups 1 and 3) was administered directly in the lung by intratracheal administration. Fifteen days after coal dust or saline instillation, the animals were sacrificed, and the femur, liver, and peripheral blood were removed. The results showed a general increase in the DNA damage values at 8 hours for all treatment groups, probably related to surgical procedures that had stressed the animals. Also, liver cells from rats treated with coal dust, pretreated or not with MLE, showed statistically higher comet assay values compared to the control group at 14 days after exposure. These results could be expected because the liver metabolizes a variety of organic compounds to more polar by-products. On the other hand, the micronucleus assay results did not show significant differences among groups. Therefore, our data do not support the antimutagenic activity of M. laevigata as a modulator of DNA damage after acute coal dust instillation.

Evaluation of mitochondrial respiratory chain activity in muscle healing by low-level laser therapy.

BACKGROUND: Recent studies demonstrate that low-level laser therapy (LLLT) modulates many biochemical processes, especially the decrease of muscle injures, the increase in mitochondrial respiration and ATP synthesis for accelerating the healing process. OBJECTIVE: In this work, we evaluated mitochondrial respiratory chain complexes I, II, III and IV and succinate dehydrogenase activities after traumatic muscular injury. METHODS: Male Wistar rats were randomly divided into three groups (n=6): sham (uninjured muscle), muscle injury without treatment, muscle injury with LLLT (AsGa) 5J/cm(2). Gastrocnemius injury was induced by a single blunt-impact trauma. LLLT was used 2, 12, 24, 48, 72, 96, and 120 hours after muscle-trauma. RESULTS: Our results showed that the activities of complex II and succinate dehydrogenase after 5days of muscular lesion were significantly increased when compared to the control group. Moreover, our results showed that LLLT significantly increased the activities of complexes I, II, III, IV and succinate dehydrogenase, when compared to the group of injured muscle without treatment. CONCLUSION: These results suggest that the treatment with low-level laser may induce an increase in ATP synthesis, and that this may accelerate the muscle healing process.

Effects of Mikania glomerata Spreng. and Mikania laevigata Schultz Bip. ex Baker (Asteraceae) extracts on pulmonary inflammation and oxidative stress caused by acute coal dust exposure.

Several studies have reported biological effects of Mikania glomerata and Mikania laevigata, used in Brazilian folk medicine for respiratory diseases. Pneumoconiosis is characterized by pulmonary inflammation caused by coal dust exposure. In this work, we evaluated the effect of pretreatment with M. glomerata and M. laevigata extracts (MGE and MLE, respectively) (100 mg/kg, s.c.) on inflammatory and oxidative stress parameters in lung of rats subjected to a single coal dust intratracheal instillation. Rats were pretreated for 2 weeks with saline solution, MGE, or MLE. On day 15, the animals were anesthetized, and gross mineral coal dust or saline solutions were administered directly in the lung by intratracheal instillation. Fifteen days after coal dust instillation, the animals were killed. Bronchoalveolar lavage (BAL) was obtained; total cell count and lactate dehydrogenase (LDH) activity were determined. In the lung, myeloperoxidase activity, thiobarbituric acid-reactive substances (TBARS) level, and protein carbonyl and sulfhydryl contents were evaluated. In BAL of treated animals, we verified an increased total cell count and LDH activity. MGE and MLE prevented the increase in cell count, but only MLE prevented the increase in LDH. Myeloperoxidase and TBARS levels were not affected, protein carbonylation was increased, and the protein thiol levels were decreased by acute coal dust intratracheal administration. The findings also suggest that both extracts present an important protective effect on the oxidation of thiol groups. Moreover, pretreatment with MGE and MLE also diminished lung inflammatory infiltration induced by coal dust, as assessed by histopathologic analyses. The present study indicates that M. glomerata and M. laevigata might become good candidates for the prevention of lung oxidative injury caused by coal dust exposure.