Effect of low intensity photobiomodulation associated with norbixin-based poly (hydroxybutyrate) membrane on post-tenotomy tendon repair. In vivo study

Abstract Purpose: To evaluate the in vivo response of photobiomodulation therapy associated with norbixin-based poly(hydroxybutyrate) membrane (PHB) in tenotomized calcaneal tendon. Methods: Thirty rats were randomly allocated to six groups (n=5 each): LED groups (L1, L2 and L3) and membrane + LED groups (ML1, ML2 and ML3). The right calcaneal tendons of all animals were sectioned transversely and were irradiated with LED daily, one hour after surgery every 24 hours, until the day of euthanasia. At the end of the experiments the tendons were removed for histological analysis. Results: The histological analysis showed a significant reduction in inflammatory cells in the ML1, ML2 and ML3 groups (p=0.0056, p=0.0018 and p<0.0001, respectively) compared to those in the LED group. There was greater proliferation of fibroblasts in the ML1 (p<0.0001) and L3 (p<0.0001) groups. A higher concentration of type I collagen was also observed in the ML1 group (p=0.0043) replacing type III collagen. Conclusion: Photobiomodulation in association with norbixin-based PHB membrane led to control of the inflammatory process. However, it did not favor fibroblast proliferation and did not optimize type I collagen formation in the expected stage of the repair process.

Characterization and assessment of the genotoxicity and biocompatibility of poly (hydroxybutyrate) and norbixin membranes

Abstract Purpose To synthesize and characterize poly(hydroxybutyrate) (PHB) and norbixin membranes to evaluate them for genotoxicity in rats and wound healing in mice by histological staining. Methods For the evaluation of genotoxicity, male rats ( Rattus novegicus ) were divided into three groups (n= 5): 5% PHB/Norbixin membrane introduced into the peritoneum by laparotomy; B - negative control; C - positive control (intraperitoneal dose of cyclophosphamide 50 mg/kg). For the evaluation of biocompatibilty, a cutaneous wound was induced on the back of males mice ( Mus musculus ) divided into two experimental treatment groups: control and membrane that underwent euthanasia after 7 and 14 days treatment. Statistical analysis ware made by One Way Anova post hoc Tukey Test (p<0.05). Results Regarding the incidence of polychromatic erythrocytes, there was no difference between negative control and 5% PHB/Norbixin membrane; however, when compared to the positive control represented by cyclophosphamide, there was a significant difference (p <0.001). As for DNA damage, the changes induced in the first 4h were repaired in 24h. In addition, the membrane was effective in abbreviating the inflammatory process and served as a scaffold due to the stimulus to reepithelialization mainly on the 7 days of treatment. Conclusion The non-genotoxic PHB/Norbixin 5% membrane presented promising results that suggest its effectiveness as a guide for tissue regeneration given its biocompatibility.

Effect of norbixin-based poly(hydroxybutyrate) membranes on the tendon repair process after tenotomy in rats

Abstract Purpose: To determine the efficacy of norbixin-based poly(hydroxybutyrate) (PHB) membranes for Achilles tendon repair. Methods: Thirty rats were submitted to total tenotomy surgery of the right Achilles tendon and divided into two groups (control and membrane; n = 15 each), which were further subdivided into three subgroups (days 7, 14, and 21; n = 5 each). Samples were analyzed histologically. Results: Histological analysis showed a significant reduction in inflammatory infiltrates on days 7, 14 (p < 0.0001 for both), and 21 (p = 0.0004) in the membrane group compared to that in the control group. There was also a significant decrease in the number of fibroblasts in the control group on days 7, 14 (p < 0.0001), and 21 (p = 0.0032). Further, an increase in type I collagen deposition was observed in the membrane group compared to that in the control group on days 7 (p = 0.0133) and 14 (p = 0.0107). Conclusion: Treatment with norbixin-based PHB membranes reduces the inflammatory response, increases fibroblast proliferation, and improves collagen production in the tendon repair region, especially between days 7 and 14.

Topical action of Buriti oil (Mauritia flexuosa L) in myositis induced in rats

Abstract Purpose: To analyze the topical effects of Buriti oil (Mauritia flexuosa L.) in induced myositis in rats. Methods: Thirty six male rats divided into three groups: Control group (C), induced myositis group (MI) and induced myositis group reated with Mauritia flexuosa L. (MT). After inducing myositis with 1% acetic acid, was topically applied 0.5 ml of Mauritia flexuosa L.extract on the posterior region of the right gastrocnemius muscle in animals belonging to group MT, for 7 and 14 days. Results: The neutrophil number there was statistically significant difference, after 7 and 14 days, between groups C and MI (p <0.001) (p<0.01). The group MT there was a significant difference in relation to MI group in both experimental times with (p<0.001). The number of fibroblasts in the 14 days showed that when comparing the groups M and MT the differences were also significant (p<0.001). As for the DLL, in 7 days, there was a significant difference between group C and MI group (p <0.001). When considering the MT group, there was a significant difference in relation to the MI group (p <0.001). Conclusion: The extract of Mauritia flexuosa L. leaves lessened acute and chronic inflammation, increased fibroblast proliferation and reduced macroscopically edema.

Action of AlGaInP laser and high frequency generator in cutaneous wound healing. A comparative study

ABSTRACT PURPOSE: To evaluate in a macroscopic, histological and histomorphometric manner the healing process of cutaneous wounds in mice. METHODS: The sample consisted of 40 male mice and was divided in four groups: 1st group (control, n=10), 2nd group (High Frequency Generator - HF, the maximum amplitude range, 120s, n=10), 3rd group (AlGaInP Laser 660 nm, 30mW power, 5 J/cm2, applying scan mode, 120s, n=10) and 4thgroup (AlGaInP Laser 660 nm, 30 mW power, 8 J/cm2, applying scan mode, n=10). The surgical incision was made with an 8 mm diameter punch perpendicularly to the back of the animal. The statistical analysis was achieved by the statistical test One Way Anova post hoc Tukey Test and significance at p<0.05 in GraphPad Prism program. RESULTS: It was observed that in the acute phase the AlGaInP Laser at 5 J/cm2 provided a greater stimulus to healing, and both lasers were effective in the remodeling phase. CONCLUSION: The AlGaInP lasers from 5 J/cm2 to 8 J/cm2 showed better biomodulatory results in the acute and remodeling phases respectively, however, the HF was less effective than the laser, providing significant benefits only in the acute phase of tissue repair.