Histological and Immunohistochemical Analysis of the Effects of Topical Melatonin Treatment Associated with Collagen Sponge and rhBMP-2 Protein on Bone Remodeling.

Extensive bone defect healing is an important health issue not yet completely resolved. Different alternative treatments have been proposed but, in face of a critical bone defect, it is still very difficult to reach a complete regeneration, with the new-formed bone presenting all morphological and physiological characteristics of a normal, preinjury bone. Topical melatonin use has shown as a promising adjuvant for bone regeneration due to its positive effects on bone metabolism. Thus, to search for new, safe, biological techniques that promote bone repair and favor defect healing, we hypothesized that there is a synergistic effect of melatonin treatment associated with rhBMP-2 to guide bone regeneration. This study aimed to investigate bone repair effects of topical melatonin administration in different concentrations (1, 10, and 100 µg), associated or not with rhBMP-2. Surgical-induced bone defect healing was qualitatively evaluated through histopathological analysis by light microscopy. Additionally, quantitative stereology was performed in immunohistochemistry-prepared tissue to identify angiogenic, osteogenic, and osteoclastogenic factors. Quantification data were compared between groups by the ANOVA/Tukey test and differences were considered significant when p < 0.05. Our results showed that the presence of the scaffold in the bone defect hindered the process of bone repair because in the group treated with "blood clot + scaffold" the results of bone formation and immunolabeling were reduced in comparison with all other groups (treated with melatonin alone or in association with rhBMP-2). Statistical analysis revealed a significant difference between the control group (bone defect + blood clot), and groups treated with different concentrations of melatonin in association with rhBMP-2, indicating a positive effect of the association for bone repair. This treatment is promising once it becomes a new safe alternative technique for the clinical treatment of fractures, bone defects, and bone grafts. Our results support the hypothesis of the safe use of the association of melatonin and rhBMP-2 and have established a safe and effective dose for this experimental treatment.

Photomodulation multiple sessions as a promising preventive therapy for medication-related osteonecrosis of the jaws after tooth extraction in rats.

The aim of this study was to evaluate the effects of photobiomodulation (PBM) with multiple sessions of low-level laser on the alveolar repair process of rats with major risk factors for medication-related osteonecrosis of the jaws (MRONJ). Senile rats received 0.45 mL of vehicle (VEH and VEH-PBM) or 0.45 mL of 100 µg/kg zoledronate (ZOL and ZOL-PBM) administrated intraperitoneally every two days during seven weeks. After three weeks of initiation of drug treatment the first lower left molar was extracted. No local treatment was performed in VEH and ZOL. VEH-PBM and ZOL-PBM were submitted to laser irradiation (660 ±â€¯10 nm; 0.035 W; 2.1 J; 60 s) on the extraction site at 0, 2 and 4 days postoperatively. Euthanasia was performed 28 days after tooth extraction. Histological sections of the hemimandible were submitted to histopathological and histomorphometric analysis, as well as to histochemistry for collagen fiber maturation and immunohistochemistry for pro-inflammatory cytokines. In ZOL, general impairment of tissue repair, areas with osteonecrosis, lower newly formed bone tissue (NFBT), smaller amount of mature collagen fibers and increased immunoreactivity for TNFα, IL-1ß and IL-6 were observed when compared to VEH and VEH-PBM. ZOL-PBM showed significant improvement in some parameters compared to ZOL, such as positive repair tissue, higher NFBT, greater amount of mature collagen fibers, besides TNFα and IL-1ß immunoreactivity decrease. Zoledronate treatment severely compromised the tissue repair process of the tooth extraction site in rats with major risk factors for MRONJ. Based on parameters employed in the present study, PBM in multiple sessions can improve the alveolar repair process, constituting a promising preventive therapy to avoid the onset of post-extraction MRONJ.

Low-intensity laser therapy efficacy evaluation in FVB mice subjected to acute and chronic arthritis.

Rheumatoid arthritis, an autoimmune inflammation, has a high prevalence in the population, and while therapy is available, it required often injection of drugs causing discomfort to patients. This study evaluates the clinical and histological effect of low-intensity laser therapy (LILT) as an alternative treatment, in a murine model of acute and chronic inflammation. FVB mice received either a Zymosan A injection into one knee joint inducing acute inflammation, followed after 15 min or 24 h by LILT or a collagen bovine type II injection emulsified in "Freund's Complete Adjuvant" to induce chronic arthritis, followed at 4 weeks with multiple LILT sessions. LILT mediated by either 660, 808, or 905 nm and tissue response was evaluated based on clinical symptoms and histological analysis of inflammatory infiltrate and damage to the articular surfaces. LILT can be effective in elevating clinical symptoms, so Kruskal-Wallis testing indicated no significant differences between knees affected by acute arthritis and treated once with LILT and an injured knee without treatment (p > 0.05) for 660 and 808 nm with some improvements for the 905-nm LILT. Mice receiving two treatments for acute arthritis showed exacerbation of inflammation and articular resorption following therapy with a 660-nm continuous laser (p < 0.05). For chronic inflammation, differences were not noted between LILT treated and untreated injured knee joints (p > 0.05). Among the lasers, the 905 nm tends to show better results for anti-inflammatory effect in acute arthritis, and the 660 nm showed better results in chronic arthritis. In conclusion, LILT wavelength selection depends on the arthritis condition and can demonstrate anti-inflammatory effects for chronic arthritis and reduced resorption area in this murine model.

Experimental tooth movement and photobiomodulation on bone remodeling in rats.

Photobiomodulation (PBM) is a therapy induced by a specific type of laser that affects biologic systems through non-thermal ways. The study of its basic mechanism has gained interest since little is known about the causes of the different effects of this treatment. In the present study, we investigated the action of the PBM application rate changes in the peri-implant tissues in rats subjected to tooth movement in different periods. Wistar rats (±250 g) received an apparatus in the region of the central incisors superiors tightly (70 g) or not, and they were also subjected to one or three PBM sessions. After 7 or 14 days, the rats were subjected to euthanasia and the jaws were dissected and processed for histology. For analysis, serial sections were made that were stained by Picrosirius Red for analysis of collagen fibers, Masson's trichrome for newly formed bone scan, and Hematoxylin-Eosin for quantification of osteoblasts. PBM applied in one or three sessions increased the population of osteoblasts. Still, the application of three sessions of PBM increased the density of collagen fibers and new bone formation compared to the controls. An increase was observed in the interincisal distance in irradiated groups with three PBM sessions and the application of force for both 7 or 14 days. These findings suggest that PBM can contribute positively to the orthodontic movement. So the laser therapy can be used as an adjunct procedure to be performed concurrently for orthodontic treatment in the dental clinic.

Corrigendum to "Herbal Mouthwash Containing Extracts of Baccharis dracunculifolia as Agent for the Control of Biofilm: Clinical Evaluation in Humans".

[This corrects the article DOI: 10.1155/2015/712683.].

Analgesia evaluation of 2 NSAID drugs as adjuvant in management of chronic temporomandibular disorders.

The aim of this triple-blind full-randomized clinical trial was to quantify analgesia in masticatory muscles and temporomandibular joints after occlusal splint therapy associated with the adjuvant administration of nonsteroidal anti-inflammatory drugs (NSAID) isolated or associated with other therapeutic agents. Pain relief was also recorded. Eighteen volunteers who had been suffering from chronic pain in masticatory muscles due to temporomandibular disorders were selected after anamnesis and assessment using RDC/TMD translated to Portuguese. The 3 proposed treatments were NSAID (sodium diclofenac), panacea (sodium diclofenac + carisoprodol + acetaminophen + caffeine), and a placebo. The total treatment duration was 10 days, preceded and succeeded by patients' pain assessment. A washout interval of 11 days was established between each therapy. All participants received all treatments in different moments, in a full randomized crossover methodology. The assessment of drug therapies was performed using visual analogue scale for pain on palpation followed by 11-point numerical scale to quantify pain during treatment. Statistical analysis has shown that, after 10 days of treatment, all therapies were effective for pain relief. NSAID therapy promoted analgesia on the third day, while placebo only promoted analgesia in the eighth day. It has been concluded that sodium diclofenac used as splint adjuvant therapy, promotes significant analgesia in a shorter time.

Herbal mouthwash containing extracts of Baccharis dracunculifolia as agent for the control of biofilm: clinical evaluation in humans.

Baccharis dracunculifolia DC (Asteraceae), popularly known as "alecrim-do-campo," is largely distributed in South America, is shown to exhibit protective actions against gastric ulcers, has anti-inflammatory properties, and is hepatoprotective. Several essential oils obtained from Baccharis species possess biological activities, such as antimicrobial and antivirus activities. This randomized controlled trial evaluated the efficacy of B. dracunculifolia in the reduction of dental biofilm, comparing this natural product with other mouthwashes already known in the dental market. In measuring the time after use of mouthwash (t = 1), there was no difference between products (P = 0.602); that is, subjects in the study had a similar PI after the first use. After one week (t = 2), there was no difference between the four products evaluated (P = 0.674), so, all research individuals completed the study with a similar reduction in dental biofilm between themselves but it was different from initial state (Friedman test). It is possible to conclude that B. dracunculifolia had the same efficiency of the materials used to oral hygiene in reduction of dental plaque and, consequently, prevention of dental caries. Thus, we can consider B. dracunculifolia as a good candidate for new material to be implemented in dental care.

Properties of the tibialis anterior muscle after treatment with laser therapy and natural latex protein following sciatic nerve crush.

INTRODUCTION: In this study we evaluated the characteristics of the tibialis anterior muscle after sciatic nerve crush and treatment with low-level laser therapy (LLLT) or the protein from natural latex (P1). METHODS: We studied the following 6 groups of male Wistar rats: control (CG); exposed nerve (EG); injured nerve (IG); injured nerve with LLLT (LG); injured nerve with P1 (PG); and injured nerve with P1 and LLLT (LPG). RESULTS: After 4 weeks, muscle morphology showed improvement in the treated groups; after 8 weeks, the treated groups resembled controls, especially the PG. Morphometry revealed muscle fiber atrophy after nerve injury, with time-dependent recovery. Histochemical analysis revealed increased intermediate fiber area. The PG was more similar to controls with NADH staining, whereas the LPG more closely resembled controls with SDH staining. CONCLUSION: Treatment using only P1 proved most efficient, revealing a negative interaction between P1 and LLLT.

Morphological and morphometric analyses of crushed sciatic nerves after application of a purified protein from natural latex and hyaluronic acid hydrogel.

Hyaluronic acid hydrogels (HAHs) have been used as a carrier of substances and factors in the repair of nervous tissue. Natural latex protein (Hevea brasiliensis, F1) has shown positive effects in treating various types of tissues, including peripheral nerves. This study evaluated the F1 associated with a HAH in a controlled crush injury (axonotmesis) of the sciatic nerve in Wistar rats. The samples were photomicrographed for morphometric and quantitative analyzes using ImageJ 1.47k software (NIH, Bethesda, MD). Morphological, quantitative (myelin area/nerve area ratio and capillary density) and morphometric (minimum nerve fiber diameter, G-Ratio) data revealed an improvement in the recovery of the sciatic nerve with the application of HAH and the combination of HAH and F1 after 4 and 8 weeks of nerve injury. The most efficacious results were observed with the combination of both substances, F1 and HAH, revealing the regenerative capacity of this new biomaterial, which was hardly tested on nerve tissue.

Ultrastructure and light microscope analysis of intact skin after a varying number of low level laser irradiations in mice.

Low level laser therapy (LLLT) has been used to relieve pain, inflammation, and wound healing processes. Thus, the skin is overexposed to laser and this effect is not completely understood. This study analyzed the effects of the number of laser applications (three, six, and 10) on the intact skin of the masseteric region in mice of strain HRS/J. The animals (n = 30) were equally divided into control (0 J/cm(2)) and irradiated (20 J/cm(2)), and each of these groups was further equally divided according to the number of laser applications (three, six, and 10) and underwent LLLT on alternate days. Samples were analyzed by light microscopy and transmission electron microscope (TEM). The animals receiving applications exhibited open channels more dilated between the keratinocytes and photobiomodulation effect on endothelial cells and fibroblasts by TEM. Under the light microscope after 10 laser applications, the type I collagen decreased (P < 0.05) compared to the three and six applications. Under these experimental conditions, all numbers of applications provided photobiomodulatory effect on the epidermis and dermis, without damage. More studies are needed to standardize the energy density and number of applications recommended for laser therapy to have a better cost-benefit ratio associated with treatment.

Application of a low-level laser therapy and the purified protein from natural latex (Hevea brasiliensis) in the controlled crush injury of the sciatic nerve of rats: a morphological, quantitative, and ultrastructural study.

This study analyzed the effects of a low-level laser therapy (LLLT, 15 J/cm(2), 780 nm wavelength) and the natural latex protein (P1, 0.1%) in sciatic nerve after crush injury (15 Kgf, axonotmesis) in rats. Sixty rats (male, 250 g) were allocated into the 6 groups (n = 10): CG-control group; EG-nerve exposed; IG-injured nerve without treatment; LG-crushed nerve treated with LLLT; PG-injured nerve treated with P1; and LPG-injured nerve treated with LLLT and P1. After 4 or 8 weeks, the nerve samples were processed for morphological, histological quantification and ultrastructural analysis. After 4 weeks, the myelin density and morphological characteristics improved in groups LG, PG, and LPG compared to IG. After 8 weeks, PG, and LPG were similar to CG and the capillary density was higher in the LG, PG, and LPG. In the ultrastructural analysis the PG and LPG had characteristics that were similar to the CG. The application of LLLT and/or P1 improved the recovery from the nerve crush injury, and in the long term, the P1 protein was the better treatment used, since only the application of LLLT has not reached the same results, and these treatments applied together did not potentiate the recovery.

Zymographic and ultrastructural evaluations after low-level laser irradiation on masseter muscle of HRS/J strain mice.

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm(2), 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups (n=5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca(+2) transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost-benefit.

Influence of low-level laser associated with osteogenic proteins recombinant human BMP-2 and Hevea brasiliensis on bone repair in Wistar rats.

This study analyzed the newly formed bone tissue after application of recombinant human BMP-2 (rhBMP-2) and P-1 (extracted from Hevea brasiliensis) proteins, 2 weeks after the creation of a critical bone defect in male Wistar rats treated or not with a low-intensity laser (GaAlAs 780 nm, 60 mW of power, and energy density dose of 30 J/cm(2)). The animals were divided into two major groups: (1) bone defect plus low-intensity laser treatment and (2) bone defect without laser irradiation. The following subgroups were also analyzed: (a) 5 µg of pure rhBMP-2; (b) 5 µg of pure P-1 fraction; (c) 5 µg of rhBMP-2/monoolein gel; (d) 5 µg of P-1 fraction/monoolein gel; (e) pure monoolein gel. Comparisons of the groups receiving laser treatment with those that did not receive laser irradiation show differences in the areas of new bone tissue. The group treated with 5 µg of rhBMP-2 and laser irradiation was not significantly different (P >0.05) than the nonirradiated group that received the same treatment. The irradiated, rhBMP-2/monoolein gel treatment group showed a lower area of bone formation than the nonirradiated, rhBMP-2/gel monoolein treatment group (P < 0.001). The area of new bone tissue in the other nonirradiated and irradiated groups was not significantly different (P > 0.05). Furthermore, the group that received the 5 µg of rhBMP-2 application showed the greatest bone formation. We conclude that the laser treatment did not interfere with the area of new bone tissue growth and that the greatest stimulus for bone formation involved application of the rhBMP-2 protein.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair.

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 µg of rhBMP-2, (3) laser and 7 µg of rhBMP-2, (4) 7 µg of rhBMP-2/monoolein gel, (5) laser and 7 µg rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

Histomorphological and angiogenic analyzes of skin epithelium after low laser irradiation in hairless mice.

It is not well-understood how low-laser therapy affects the skin of the applied area. This study analyzes skin of the masseteric region of mice from the HRS/J strain after three different application regimens (three, six or ten applications per regimen) of low intensity laser at 20 J/cm(2) and 40 mW for 20 sec on alternate days. Three experimental groups according to the number of laser applications (three, six or ten) and three control groups (N = 5 animals for each group) were used. On the third day after the last irradiation, all animals were sacrificed and the skin was removed and processed to analyze the relative occupation of the test area by each epithelial layer and the aspects of neovascularization. Data were submitted to statistical analyzes. The irradiated groups compared to their respective controls at each period of time, showed no significant difference in relative occupation of the test area by the layers and epithelium areas for three and six applications, but for ten applications, a significant decrease (P < 0.05) in the basal and granulosum layers, and epithelium areas were found. From the comparisons of the three irradiated groups together, the group with six laser applications showed statistical difference (P < 0.05) in total epithelium and on the layers. Vascular endothelial growth factor (VEGF) and VEGFR-2 immunoreactivities were similar for the control and irradiated groups. Results suggested a biostimulatory effect with low risks associated with superficial tissues, when the treatment aims the deeper layers after six applications.

Effects of low-level laser therapy on the oxidative metabolism and matrix proteins in the rat masseter muscle.

OBJECTIVE: This study aims to analyze the effects of low-level laser therapy (LLLT) on the oxidative activity and the expression/activity of metalloproteinases of the masseter muscle. BACKGROUND DATA: Currently in dentistry LLLT has been used on patients with muscular disorders, such as the temporomandibular disorders (TMDs) but its effect at the cellular level has not been fully elucidated. METHODS: Thirty male Wistar rats divided into 6 groups (n=5) received 10 laser irradiations (780 nm, 5 mmW, CW laser, illuminated area 0.04 cm(2), power density 125 mW/cm(2)), with different energy densities (group I-0; group II-0.5; group III-1.0; group IV-2.5; group V-5.0; and group VI-20 J/cm(2)). Muscles were processed for nicotinamide adenine dinucleotide diaphorase (NADH) and sucinate dehydrogenase (SDH) activities and zymography. The photomicrographs were evaluated by the point counting method using a test system and ImageJ software; and by the ANOVA statistical test. The proteinases' secretion/activity was qualitatively analyzed by zymography. RESULTS: LLLT significantly increased (p<0.05) masseter muscle oxidative metabolism shown by the increased area of intermediary fibers in the NADH (groups IV, V, and VI) and SDH (group V) reactions. The same metabolic pattern was observed among the groups in both reactions. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) zymography detected only the MMP-2 expression/activity for the untreated-control group (group I). The exposure to LLLT increased the activity of MPP-2 in group VI and the activity of MMP-9 in all groups exposed to different energy densities of laser irradiation (groups II, III, IV, V, and VI). CONCLUSIONS: Thus, LLLT stimulated the oxidative metabolism and the expression of matrix metalloproteinase (MMPs) of the masseter muscle, which may indicate a matrix remodeling process. However, group VI did not show the best results for oxidative metabolism, probably indicating that the dosage they were given was high for this protocol.

Application of low-level laser irradiation (LLLI) and rhBMP-2 in critical bone defect of ovariectomized rats: histomorphometric evaluation.

OBJECTIVES: The aim of this study was to evaluate the osteogenic potential of recombinant human bone morphogenetic protein-2 (rhBMP-2) and low-level laser irradiation (LLLI), isolated or combined in critical bone defects (5 mm) in parietal bone using ovariectomized female rats as an experimental animal model. MATERIALS AND METHODS: Forty-nine female Wistar rats, bilaterally ovariectomized (OVX), were divided into seven treatment groups of seven animals each: (I) laser in a single application, (II) 7 µg of pure rhBMP-2, (III) laser and 7 µg of pure rhBMP-2, (IV) 7 µg of rhBMP-2/monoolein gel, (V) laser and 7 µg of rhBMP-2/monoolein gel, (VI) laser and pure monoolein gel, and (VII) critical bone defect controls. The low-level laser source used was a gallium aluminum arsenide semiconductor diode laser device (λ = 780 nm, D = 120 J/cm(2)). RESULTS: Groups II and III presented higher levels of newly formed bone than all other groups with levels of 40.57% and 40.39%, respectively (p < 0.05). The levels of newly formed bone of groups I, IV, V, and VI were similar with levels of 29.67%, 25.75%, 27.75%, and 30.64%, respectively (p > 0.05). The area of new bone formation in group VII was 20.96%, which is significantly lower than groups I, II, III, and VI. CONCLUSIONS: It was concluded that pure rhBMP-2 and a single dose of laser application stimulated new bone formation, but the new bone formation area was significantly increased when only rhBMP-2 was used. Additionally, the laser application in combination with other treatments did not influence the bone formation area.

Low-level laser intensity application in masseter muscle for treatment purposes.

OBJECTIVE: This study evaluated with histochemical analysis how the number of laser applications can affect the masseter muscle. BACKGROUND: In dentistry today, the laser is used in patients with temporomandibular disorders (TMDs), mainly for radiating pain in the masticatory muscles, whose origins may be associated with malocclusion, although the laser effects are not well understood on the cellular level. MATERIALS AND METHODS: Thirty mice (HRS/J lineage) were randomly distributed into groups according to the number of laser applications (three, six, and 10). For each group of laser applications (experimental, n = 5), it was considered the control group (n = 5), which was not irradiated. All animals inhaled halothane (2-bromo-2-chloro-1, 1, 1-trifluoroethane, minimum 99%, Sigma Aldrich, India) before each laser irradiation performed on the left masseter muscle region, on alternate days with 20 J/cm(2), 40 mW, for 20 sec. The muscle samples were collected for histochemical analysis with succinate dehydrogenase (SDH) enzyme 72 h after the last application. RESULTS: (a) A decrease in area of light fibers type (35.91% ± 6.9%; 32.08% ± 6.3%, and 27.88% ± 6.3%), according to the increase of laser applications (p < 0.05); (b) significant increase (p < 0.05) in the area of intermediate fibers, with an increase of laser application (11.08% ± 3.9%; 16.52% ± 5.7%, and 15.96% ± 3.9%), although the increase with 10 applications was small; (c) area increase of dark fibers in the group with three laser applications (0.16% ± 0.3%) (p < 0.05), and in groups with six and 10 laser applications, respectively (9.68% ± 6.0% and 9.60% ± 4.0%). CONCLUSIONS: The SDH enzyme activity revealed that the number of laser applications increases the metabolic pattern of the muscle fibers. A minimal difference in metabolic activity between six and 10 applications of a laser suggests that further analyses should be done to confirm that six applications are enough to produce the same clinical effects, thereby contributing data to professionals from different fields in regard to the cost-benefit ratio of this therapy.

Evaluation of rhBMP-2 and natural latex as potential osteogenic proteins in critical size defects by histomorphometric methods.

This in vivo study evaluated the osteogenic potential of two proteins, recombinant human bone morphogenetic protein-2 (rhBMP-2) and a protein extracted from natural latex (Hevea brasiliensis, P-1), and compared their effects on bone defects when combined with a carrier or a collagen gelatin. Eighty-four (84) Wistar rats were divided into two groups, with and without the use of collagen gelatin, and each of these were divided into six treatment groups of seven animals each. The treatment groups were: (1) 5 microg of pure rhBMP-2; (2) 5 microg of rhBMP-2/monoolein gel; (3) pure monoolein gel; (4) 5 microg of pure P-1; (5) 5 microg of P-1/monoolein gel; (6) critical bone defect control. The animals were anesthetized and a 6 mm diameter critical bone defect was made in the left posterior region of the parietal bone. Animals were submitted to intracardiac perfusion after 4 weeks and the calvaria tissue was removed for histomorphometric analysis. In this experimental study, it was concluded that rhBMP-2 allowed greater new bone formation than P-1 protein and this process was more effective when the bone defect was covered with collagen gelatin (P < 0.05).

Ultrastructural analysis of the low level laser therapy effects on the lesioned anterior tibial muscle in the gerbil.

Low level laser therapy (LLLT) is known for its positive results but studies on the biological and biomodulator characteristics of the effects produced in the skeletal muscle are still lacking. In this study the effects of two laser dosages, 5 or 10 J/cm(2), on the lesioned tibial muscle were compared. Gerbils previously lesioned by 100 g load impact were divided into three groups: GI (n=5) controls, lesion non-irradiated; GII (n=5), lesion irradiated with 5 J/cm(2) and GIII (n=5), lesion irradiated with 10 J/cm(2), and treated for 7 consecutive days with a laser He-Ne (lambda=633 nm). After intracardiac perfusion, the muscles were dissected and reduced to small fragments, post-fixed in 1% osmium tetroxide, dehydrated in increasing alcohol concentrations, treated with propylene oxide and embedded in Spurr resin at 60 degrees C. Ultrafine cuts examined on a transmission electron microscope (Jeol 1010) revealed in the control GI group a large number of altered muscle fibers with degenerating mitochondria, intercellular substance containing degenerating cell fragments and budding blood capillaries with underdeveloped endothelial cells. However, groups GII and GIII showed muscle fibers with few altered myofibrils, regularly contoured mitochondria, ample intermembrane spaces and dilated mitochondrial crests. The clean intercellular substance showed numerous collagen fibers and capillaries with multiple abluminal processes, intraluminal protrusions and several pinocytic vesicles in endothelial cells. It was concluded that laser dosages of 5 or 10 J/cm(2) delivered by laser He-Ne (lambda=633 nm) during 7 consecutive days increase mitochondrial activity in muscular fibers, activate fibroblasts and macrophages and stimulate angiogenesis, thus suggesting effectivity of laser therapy under these experimental conditions.