Efficiency analysis of commercial polymeric membranes for bone regeneration in rat cranial defects

Purpose: To evaluate the in vivo efficiency of commercial polymeric membranes for guided bone regeneration. Methods: Rat calvarial critical size defects was treated with LuminaCoat (LC), Surgitime PTFE (SP), GenDerm (GD), Pratix (PR), Techgraft (TG) or control (C-) and histomorphometric analysis determined the percentage of new bone, connective tissue and biomaterial at 1 or 3 months. Statistical analysis used ANOVA with Tukey's post-test for means at same experimental time and the paired Student's t test between the two periods, considering p < 0.05. Results: New bone at 1 month was higher for SP, TG and C-, at 3 months there were no differences, and between 1 and 3 months PR had greater increase growthing. Connective tissue at 1 month was higher for C-, at 3 months for PR, TG and C-, and between 1 and 3 months C- had sharp decline. Biomaterial at 1 month was higher for LC, in 3 months for SP and TG, and between 1 and 3 months, LC, GD and TG had more decreasing mean. Conclusion: SP had greater osteopromotive capacity and limitation of connective ingrowth, but did not exhibit degradation. PR and TG had favorable osteopromotion, LC less connective tissue and GD more accelerated biodegradation.

Development and characterization of poultry collagen-based hybrid hydrogels for bone regeneration

Purpose: Poultry by-products can contribute as an innovative natural source for the development of composites based on polymers and minerals aiming at bone regeneration. The objective of this study was the physicochemical and biological characterization of collagen-based hydrogels crosslinked with ultraviolet (UV)-riboflavin. Methods: Pure hydrogels of 100% collagen (G1) or hybrid hydrogels, 90% collagen:10% apatite (G2), 90% collagen:10% nanokeratin (G3), and 90% collagen:5% apatite:5% nanokeratin (G4) were characterized by scanning electron microscope, Fourier-transform infrared spectroscopy, differential scanning calorimetry, swelling degree and quali-quantitative histological analysis. Ectopic implantation in subcutaneous tissue in mice at one, three and nine weeks allowed to assess the inflammation (neutrophils, lymphocytes, macrophages, and giant cells) and repair (neovascularization, and connective tissue) to determine biocompatibility and the integrity of biomaterials to score their biodegradability. Histomorphometry on critical size defects in rat calvaria at one and three months evaluated the percentage of bone, connective tissue, and biomaterials in all groups. Results: The hydrogels presented porous microstructure, water absorption and physicochemical characteristics compatible with their polymeric and/or mineral composition. All materials exhibited biocompatibility, biodegradability, and low osteoconductivity. G2 showed greater density of new bone and biomaterial than the G1, G3 and G4. Conclusions: The collagen-apatite group formulation suggests potential for development as osteopromoting membrane.

Comparison of three different strategies to treat sciatic nerve regeneration: an experimental study

Purpose: To compare the effect of vein conduit filled with adipose tissue stem cells (ASC) on peripheral nerve injury regeneration. Methods: We analyzed 30 male Wistar rats surgically submitted to a 5-mm gap on the sciatic nerve. Then, the animals were divided into three groups: nerve autografting (AG, n=10), autogenous inverted glycerol-conserved vein (VG, n=10), and autogenous inverted glycerol-conserved vein + ASC (VASCG, n=10). The study endpoints were neuromotor functional analysis, gastrocnemius muscle weight, and sciatic nerve graft histomorphometry analysis. In the histologic analysis, we added a control group (naïve nerve). Results: Regarding functional analysis (Walking tract- score), the findings at week 3 showed a difference between the AG and the VG (-96.6 vs. -59.6, p=0.01, respectively) and between the VG and the inverted vein + VASCG (-59.9 vs. -88.92, p=0.02). At week 12, this study showed a difference between the AG and the VG (-64.8 vs. -47.3, p=0.004, respectively), and also a difference between the VG and the VASCG (-47.3 vs. -57.4, p=0.02, respectively). There was no difference in the histomorphometry analysis (nerve diameter, Schwann cells counting). The gastrocnemius muscles on the intervention side were more atrophic when compared to the gastrocnemius muscles on the control side. Conclusions: Our results suggested better functional recovery in the inverted vein group when compared to control group, and inverted vein + ASC group.

Histopathological, immunohistochemical and biochemical alterations in liver tissue after fungicide-mancozeb exposures in Wistar albino rats

Purpose: To evaluate the histopathological, immunohistochemical, and biochemical effects of liver changes after mancozeb administration. Methods: Rats were divided into groups­the control group (n=7) and the mancozeb group (n=7)­, given 500 mg/kg mancozeb dissolved in corn oil daily for four weeks by an orogastric tube. Caspase-3 and tumor necrosis factor-alpha (TNF-α) primary antibodies were used for immunohistochemical analysis. Results: Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values of the mancozeb group increased significantly than ones of the control group. Venous dilatation, inflammation, hepatocyte degeneration, TNF-α, and caspase-3 expression scores increased significantly in the mancozeb group. In the mancozeb group, intensive caspase-3 expression was observed in hepatocyte cells around the central vein in the center of the liver lobule, and there was an increase in TNF-α expression in the inflammatory cells around the enlarged central vein and Kupffer cells and apoptotic hepatocyte cells. Conclusions: Subacute mancozeb exposure in rats leads to elevated toxicity with impaired liver function, increased inflammation in tissue and increased apoptosis due to cellular damage in the liver, and decreased liver regeneration ability due to congestion and degeneration of blood vessels.

Use of aerobic treadmill exercises on nerve regeneration after sciatic nerve injury in spontaneously hypertensive rats

Purpose: Various postoperative protocols have been proposed to improve outcomes and accelerate nerve regeneration. Recently, the use of physical exercise in a post-surgical neurorraphy procedure has shown good results when started early. We experimentally investigated the hypothesis that post-operative exercise speeds up results and improves clinical and morphologic parameters. Methods: Isogenic rats were randomly divided into four groups: 1 SHAM; 2 SHAM submitted to the exercise protocol (EP); 3 Grafting of the sciatic nerve; and 4 Grafting of the sciatic nerve associated with the EP. The EP was based on aerobic activities with a treadmill, with a progressive increase in time and intensity during 6 weeks. The results were evaluated by the sciatic functional index (SFI), morphometric and morphologic analysis of nerve distal to the lesion, and the number of spinal cord motor neurons, positive to the marker Fluoro-Gold (FG), captured retrogradely through neurorraphy. Results: Functional analysis (SFI) did not show a statistical difference between the group grafted with (­50.94) and without exercise (-65.79) after 90 days. The motoneurons count (Spinal cord histology) also showed no diference between these groups (834.5 × 833 respectively). Although functionally there is no difference between these groups, morphometric study showed a greater density (53.62) and larger fibers (7.762) in GRAFT group. When comparing both operated groups with both SHAM groups, all values were much lower. Conclusions: The experimental model that this aerobic treadmill exercises protocol did not modify nerve regeneration after sciatic nerve injury and repair with nerve graft.

Influence of silver nanoparticles on the tissue reaction of polyacrylic acid-based gel

Purpose: To study the influence of silver nanoparticles (AgNP) on tissue reaction when incorporated into a polymeric matrix of polyacrylic acid-based (Carbopol®) gel as a proposal for a new low-cost type of biomaterial that is simple to manufacture for use as an antimicrobial and antioxidative dressing. Methods: In-vivo tests of implantation in the subcutaneous tissue of the back of rats were performed using polyethylene tubes in three situations: empty, only the gel, and gel incorporated with AgNP. Then, the tissue reaction was studied by counting inflammatory cells. Additionally, in-vitro tests of the antioxidative and antimicrobial activity of AgNP were performed. The radical 2,2 diphenyl-1 picrylhydrazyl (DPPH) was used to test the antioxidative activity of AgNP using electron spin resonance. The antimicrobial activity of AgNP was determined by minimum inhibitory concentration against the microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Results: The results indicated that AgNP presents antioxidative activity and was able to inhibit the growth of the microorganisms tested. The addition of AgNP in Carbopol® did not alter the tissue inflammatory response (p>0.05, Kruskal-Wallis's test). Conclusions: The new biomaterial is promising for future use as a dressing for its beneficial properties for regenerative processes

Histone deacetylase inhibitor givinostat has ameliorative effect in the colitis model

Purpose: To investigate the effect of givinostat treatment in acetic acid-induced ulcerative colitis model in rats. Methods: Thirty male Wistar albino rats were used. Rats were randomly divided into three equal groups, and colitis was induced on 20 rats by rectal administration of %4 solutions of acetic acid. Twenty rats with colitis were randomly divided into two groups. %0.9 NaCl (saline) solution was administered intraperitoneally to the first group of rats (saline group, n=10) at the dose of 1 mL/kg/day. Givinostat was administered intraperitoneally to the second group rats (Givinostat group, n=10) at the dose of 5 mg/kg/day. Samples were collected for biochemical analysis. Colon was removed for histopathological and biochemical examinations. Results: Plasma tumor necrosis factor-α (TNF-α), pentraxin-3 (PTX-3), and malondialdehyde levels were significantly decreased in the givinostat group compared to the saline group (p<0.05, p<0.001, and p<0.001 respectively; p<0.001, p<0.001, and p<0.001, respectively). Colon TNF-α and prostaglandin F2 alpha (PGF-2) levels were significantly decreased (p<0.05, and p<0.001, respectively). The givinostat group had a significantly lower histologic score than saline group (p<0.001, and p<0.001, respectively). Conclusions: Givinostat, a good protector and regenerator of tissue and an anti-inflammatory agent, may be involved in the treatment of colitis in the future.

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

Abstract Background: The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.(AU)

Evaluation of mesenchymal cells and dapsone for the treatment of dermonecrotic wounds caused by Loxosceles laeta venom in rabbits / Avaliação de células mesenquimais e dapsona para o tratamento de feridas dermonecróticas causadas pelo veneno de Loxosceles laeta em coelhos

This study aimed to evaluate the efficacy of mesenchymal stem cells (MSC), alone or associated with dapsone (DAP), in treating dermonecrotic wounds caused by Loxosceles laeta venom. Twenty-five male rabbits were distributed into five groups. Negative control received ultrapure water (C-), whilst all other groups were injected with 20 μg of L. laeta venom. After 4 hours, each group received one of the following treatments: PBS (C+), DAP, MSC, and DAP+MSC. Animals were evaluated daily and photographic records made for analysis of wound area. Twelve days after, animals were euthanized and skin samples removed for histological analysis. We observed that DAP showed the best percentage of wound contraction at day 3. In the treatments using MSCs, a negative value of wound contraction was observed for the isolated MSCs, as well as a lower contraction value for the association of the MSC + DAP when compared to PBS, probably, by the increase in initial infammation after the application of stem cells, due to the fact that MSCs secrete a broad spectrum of bioactive molecules such as cytokines and growth factors that favor regeneration. Histologically, it was observed that animals of C+ showed extensive areas of necrosis, ulcers, neutrophilic infiltrate, and mineralization. Collagen deposition showed increase in MSC+DAP treatment, however vascularization remained unchanged. This is the first report using MSC and MSC+DAP as a treatment for cutaneous loxoscelism and more studies are needed to determine its use as an alternative therapy for dermonecrotic lesions caused by Loxosceles spider.

Este estudo teve como objetivo avaliar a eficácia das células-tronco mesenquimais (CTMs), isoladas ou associadas à dapsona (DAP), no tratamento de feridas dermonecróticas causadas pelo veneno de Loxosceles laeta. Vinte e cinco coelhos machos foram distribuídos em cinco grupos. O controle negativo recebeu água ultrapura (C-), enquanto todos os outros grupos foram injetados com 20 μg de veneno de L. laeta. Após 4 horas, cada grupo recebeu um dos seguintes tratamentos: PBS (C+), DAP, CTMs e DAP + CTMs. Os animais foram avaliados diariamente durante 12 dias, e feitos registros fotográficos para análise da ferida e no 12º dia, foram eutanasiados e, retiradas amostras de pele para análise histológica. Observou-se que a DAP apresentou o melhor percentual de contração da ferida no terceiro dia. Nos tratamentos com CTMs, observou-se uma contração negativa da ferida tanto para as CTMs isoladas, bem como a associação CTMs + DAP em relação ao PBS, possivelmente, pelo aumento da infamação inicial após a aplicação de células-tronco. Isso é devido ao fato de que as CTMs secretam um amplo espectro de moléculas bioativas como citocinas e fatores de crescimento que favorecem a regeneração. Histologicamente, observou-se que os animais de C+ apresentaram extensas áreas de necrose, úlceras, infiltrado neutrofílico, além de mineralização. Houve aumento de deposição de colágeno no tratamento CTMs + DAP, no entanto, a vascularização permaneceu inalterada. Este é o primeiro relato usando CTMs e CTMs + DAP como tratamento para loxoscelismo cutâneo e mais estudos são necessários para determinar seu uso como terapia alternativa para lesões demonecróticas causadas pela aranha Loxosceles.

Tissue healing changes on wounds in rats after treatment with Hancornia speciosa latex in cream-gel formulation

Purpose: Hancornia speciosa latex has shown pharmacological potential in wound healing processes due to its angiogenic, osteogenic, and anti-inflammatory activities. The aims of this study were to carry out a cream-gel formulation with 5, 10 and 25% of H. speciosa serum latex and to evaluate its potential to stimulate the skin regeneration in rats' wounds. Methods: One hundred and twenty rats were divided into five groups: neutral control with saline (G1), cream-gel based on H. speciosa latex serum at 5% m/v (G2), cream-gel at 15% m/v (G3), cream-gel at 25% m/v (G4), and cream-gel (G5). The animals were euthanized at three, seven, 14 and 21 days after the injury induction, and some parameters were analyzed: wound contraction, necrosis, fibrin, polymorphonuclear and mononuclear infiltrates, fibroblast, angiogenesis, hemorrhage, and collagen. Results:The therapeutic treatment with cream-gel at 15 and 25% is beneficial in the inflammatory phase of healing processes since it increased the angiogenesis and proliferation of mononuclear infiltrations in wounds. Regarding wound contraction, the treatment with cream-gel (5 and 15%) induced a higher rate of contraction in the proliferative phase. The 15% cream-gel formulation stimulated a greater production of collagen in the injured tissues. Conclusions: H. speciosa cream-gel is a low-cost herbal medicine which can aid in tissue repair.

Comparison of two different biomaterials in the bone regeneration (15, 30 and 60 days) of critical defects in rats

ABSTRACT Purpose To evaluate and compare two types of different scaffolds in critical bone defects in rats. Methods Seventy male Wistar rats (280 ± 20 grams) divided into three groups: control group (CG), untreated animals; biomaterial group 1 (BG1), animals that received the scaffold implanted hydroxyapatite (HA)/poly(lactic-co-glycolic) acid (PLGA); and biomaterial group 2 (BG2), animals that received the scaffolds HA/PLGA/Bleed. The critical bone defect was induced in the medial region of the skull calotte with the aid of an 8-mm-diameter trephine drill. The biomaterial was implanted in the form of 1.5 mm thick scaffolds, and samples were collected after 15, 30 and 60 days. Non-parametric Mann-Whitney test was used, with the significance level of 5% (p ≤ 0.05). Results Histology revealed morphological and structural differences of the neoformed tissue between the experimental groups. Collagen-1 (Col-1) findings are consistent with the histological ones, in which BG2 presented the highest amount of fibers in its tissue matrix in all evaluated periods. In contrast, the results of receptor activator of nuclear factor kappa-Β ligand (Rank-L) immunoexpression were higher in BG2 in the periods of 30 and 60 days, indicating an increase of the degradation of the biomaterial and the remodeling activity of the bone. Conclusions The properties of the HA/PLGA/Bleed scaffold were superior when compared to the scaffold composed only by HA/PLGA.

Biological behavior of magnesium-substituted hydroxyapatite during bone repair / Comportamento biológico de hidroxiapatita substituída com magnésio durante o reparo ósseo

The aim of this study was to analyze the biological behavior and osteogenic potential of magnesium (Mg) substituted hydroxyapatite (HA) microspheres, implanted in a critical bone defect, considering that this ion is of great clinical interest, since it is closely associated with homeostasis and bone mineralization. For the purpose of this study, 30 rats were used to compose three experimental groups: GI - bone defect filled with HA microspheres; GII - bone defect filled with HA microspheres replaced with Mg; GIII - empty bone defect; evaluated at biological points of 15 and 45 days. The histological results, at 15 days, showed, in all the groups, a discrete chronic inflammatory infiltrate; biomaterials intact and surrounded by connective tissue; and bone neoformation restricted to the borders. At 45 days, in the GI and GII groups, an inflammatory response of discrete granulomatous chronic type was observed, and in the GIII there was a scarce presence of mononuclear inflammatory cells; in GI and GII, the microspheres were seen to be either intact or fragmented, surrounded by fibrous connective tissue rich in blood vessels; and discrete bone neoformation near the edges and surrounding some microspheres. In GIII, the mineralization was limited to the borders and the remaining area was filled by fibrous connective tissue. It was concluded that the biomaterials were biocompatible and osteoconductive, and the percentage of Mg used as replacement ion in the HA did not favor a greater bone neoformation in relation to the HA without the metal.(AU)

O objetivo deste estudo foi analisar o comportamento biológico de microesferas de hidroxiapatita (HA) substituída com magnésio (Mg) durante o reparo de defeito ósseo crítico, tendo em vista que este íon é de grande interesse clínico, pois está intimamente associado à homeostasia e à mineralização óssea. Para tanto, utilizou-se 30 ratos para compor três grupos experimentais: GI - defeito ósseo preenchido com microesferas de HA; GII - defeito ósseo preenchido com microesferas de HA substituída com Mg; GIII (controle) - defeito ósseo vazio; avaliados nos pontos biológicos de 15 e 45 dias. Os resultados histológicos evidenciaram, aos 15 dias, discreto infiltrado inflamatório crônico e neoformação óssea restrita às bordas, em todos os grupos. Nos grupos GI e GII, os biomateriais mantiveram-se íntegros e circundados por tecido conjuntivo frouxo. Aos 45 dias, notou-se resposta inflamatória do tipo crônica granulomatosa discreta nos grupos GI e GII, e no GIII presença escassa de células inflamatórias mononucleares. As microesferas implantadas no GI e GII mantiveram-se, em sua maioria, íntegras e envolvidas por tecido conjuntivo fibroso. Notou-se discreta neoformação óssea próxima às bordas e circunjacente a algumas microesferas. No GIII, a mineralização limitou-se às bordas e a área remanescente foi preenchida por tecido conjuntivo fibroso. Conclui-se que os biomateriais foram biocompatíveis, bioativos, osteocondutores e apresentaram biodegradação lenta, indicando seu grande potencial para em aplicações clínica como biomaterial de preenchimento.(AU)

Effect of S53P4 bioactive glass and low-level laser therapy on calvarial bone repair in rats submitted to zoledronic acid therapy

ABSTRACT Purpose To evaluate the influence of bioactive glass and photobiomodulation therapy (PBMT) in calvarial bone repair process in rats submitted to zoledronic acid therapy. Methods Twenty-four rats were selected and treated with the dose of 0.035 mg/kg of zoledronic acid every two weeks, totalizing eight weeks, to induce osteonecrosis. After the drug therapy, surgical procedure was performed to create 5-mm diameter parietal bone defects in the calvarial region. The rats were then randomly assigned to groups according to the following treatments: AZC: control group, treated with blood clot; AZBIO: bone defect filled with bioactive glass; AZL: treated with blood clot and submitted to PBMT; and AZBIOL: treated with bioactive glass S53P4 and submitted to PBMT. Tissue samples were collected and submitted to histomorphometric analysis after 14 and 28 days. Results At 14 days, bone neoformation in the AZBIO (52.15 ± 9.77) and AZBIOL (49.77 ± 13.58) groups presented higher values (p ≤ 0.001) compared to the AZC (23.35 ± 10.15) and AZL groups (23.32 ± 8.75). At 28 days, AZBIO (80.24 ± 5.41)still presented significant higher bone recovery values when compared to AZC (59.59 ± 16.92)and AZL (45.25 ± 5.41) groups (p = 0.048). In the 28-day period, the AZBIOL group didn't show statistically significant difference with the other groups (71.79 ± 29.38). Conclusions The bioactive glass is an effective protocol to stimulate bone neoformation in critical defects surgically created in rats with drug induced osteonecrosis, in the studied periods of 14 and 28 days.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Avaliação da eficácia do sistema rigeneracon no tratamento de lesões de calvária em ratos / [Evaluation of the efficacy of the rigeneracon system in the treatment of calvary injuries in rats]

Defeitos ósseos constituem um problema de saúde global. O sistema Rigenera permite a extração de microenxertos ricos em células-tronco mesenquimais (CTMs). Objetivou-se avaliar o processo de regeneração óssea por enxertos obtidos pelo sistema Rigenera em defeitos críticos na calvária de ratos. Foram utilizados 18 ratos Wistar, machos, pesando 285±29g, distribuídos em três grupos (n=6), sendo cada animal controle de si mesmo, denominados G15-Controle e G15-Tratado (15 dias); G30-Controle e G30-Tratado (30 dias) e G60-Controle e G60-Tratado (60 dias). Foram realizadas duas lesões de 5mm de diâmetro em cada antímero da calvária. Nos grupos tratados, foram utilizados microenxertos autólogos de cartilagem xifoide, obtidos pelo sistema Rigenera. O defeito contralateral serviu como controle em todos os animais. Os animais foram eutanasiados aos 15, 30 e 60 dias após a cirurgia, e as amostras foram processadas para a histoquímica. Nos grupos controle, não foram observados sinais de regeneração óssea, enquanto nos grupos tratamento foram verificadas áreas de formação óssea e tecido mesenquimal ativado. O sistema Rigenera foi eficiente na obtenção de microenxertos autólogos, para terapia celular em defeito crítico de calvária de ratos. Com o aprimoramento do protocolo, o sistema Rigenera poderá ser amplamente utilizado no tratamento de lesões ósseas.(AU)

Bone defects are a global health problem. The Rigenera system allows the extraction of micro grafts rich in mesenchymal stem cells (MSCs). The objective of this study was to evaluate the bone regeneration process by grafts obtained by the Rigenera system in defects in the rats calvarian. Eighteen male Wistar rats were used, weighing 285 ± 29g, distributed in three groups (n = 6), where each animal was treatment and control, called G15-Control and G15-Treated (15 days); G30-Control and G30-Treated (30 days) and G60-Control and G60-Treated (60 days). Two 5mm diameter lesions were performed on each calvaria side. In the treated groups, autologous micrograft from xiphoid cartilage, obtained by the Rigenera system, were used. The other defect served as a control in all animals. The animals were euthanized at 15, 30 and 60 days after the surgery and the samples were processed for histochemistry. In the control groups, no signs of bone regeneration were observed, while in the treatment groups, areas of bone formation and activated mesenchymal tissue were verified. The Rigenera system was efficient in obtaining autologous micrograft for cell therapy in a critical calvaria defect in rats. Rigenera system can be widely used in the treatment of bone injuries.(AU)

Biological compatibility of oxidized cellulose vs. porcine gelatin to control bleeding in liver lesions in rats

ABSTRACT Purpose: To compare biological compatibility, hemostasis, and adhesion formation between oxidized regenerated cellulose and lyophilized hydrolyzed porcine collagen in liver trauma. Methods: Forty male Wistar rats constituted two groups: group A (oxidized cellulose) and group B (lyophilized hydrolyzed collagen). Standardized liver trauma was made, and the hemostatic agent was applied. Animals in subgroups A7 and B7 were submitted to euthanasia and relaparotomy after seven days, and in subgroups A14 and B14 after 14 days. Macroscopic and microscopic results were evaluated. Results: There was no fluid in the cavity in any of the animals, and adhesions were present in all of them. In the analysis after seven days, the adhesions were grades 3 or 4 and consisted of omentum, small intestine, and abdominal wall (p<0.05). In both groups, the mesh was surrounded by a capsule, which was not observed after 14 days. In the evaluation after 14 days, adhesions were grades 2 or 3 (p>0.05). The microscopic examination showed subacute and chronic reactions, in both groups and in both timepoints, with similar frequency. The intensity of fibrosis always presented positive scores. Microabscesses and xanthomatous macrophages were observed in both groups. Conclusions: There was no superiority of one agent over the other.

In vitro evaluation of hydroxyapatite, chitosan, and carbon nanotube composite biomaterial to support bone healing / Avaliação in vitro do biomaterial compósito à base de hidroxiapatita, quitosana e nanotubo de carbono como adjuvante no reparo ósseo

Hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were developed to improve bone healing. Previous studies suggested that a combination of biomaterials and mesenchymal stem cells (MSCs) can potentially help promote bone regeneration. In the present study, we first developed hydroxyapatite, chitosan, and carbon nanotube composite biomaterial. Then, the effect of different concentrations of the extract on the viability of Vero cells (ATCC CCL-81) and MSCs obtained from sheep bone marrow using methylthiazol tetrazolium (MTT) and propidium iodide (PI) assays were evaluated. The biomaterial group demonstrated an absence of cytotoxicity, similar to the control group. Samples with 50% and 10% biomaterial extract concentrations showed higher cell viability compared to samples from the control group (MTT assay). These results suggest that the presence of this composite biomaterial can be used with MSCs. This study also concluded that hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were not cytotoxic. Therefore, these could be used for performing in vivo tests.(AU)

O compósito à base de hidroxiapatita, quitosana e nanotubo de carbono foi desenvolvido com o intuito de auxiliar na consolidação óssea. Estudos anteriores sugerem que a combinação de substitutos ósseos e células-tronco mesenquimais (CTM) podem auxiliar a potencializar e promover a regeneração óssea. No presente estudo, o biomaterial foi desenvolvido e a viabilidade e a citotoxicidade de células Vero (ATCC CCL-81) e CTM obtidas de medula óssea provenientes de ovinos utilizando ensaios metil-tiazol-tetrazólio, MTT e iodeto de propídeo (PI) foram avaliadas em diferentes concentrações de extrato desse compósito. O compósito demonstrou ausência de citotoxicidade com comportamento semelhante ao grupo controle. Amostras com 50% e 10% de concentração de extrato do compósito mostraram resultados maiores comparados ao grupo controle (ensaio MTT). Esses resultados também sugerem que a presença do biomaterial pode ser utilizada em associação a CTM. Assim, esse estudo conclui que o compósito apresentado de hidroxiapatita, quitosana e nanotubo de cabono não foi considerado citotóxico e pode ser utilizado em teste in vivo.(AU)

In vitro evaluation of hydroxyapatite, chitosan, and carbon nanotube composite biomaterial to support bone healing / Avaliação in vitro do biomaterial compósito à base de hidroxiapatita, quitosana e nanotubo de carbono como adjuvante no reparo ósseo

Hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were developed to improve bone healing. Previous studies suggested that a combination of biomaterials and mesenchymal stem cells (MSCs) can potentially help promote bone regeneration. In the present study, we first developed hydroxyapatite, chitosan, and carbon nanotube composite biomaterial. Then, the effect of different concentrations of the extract on the viability of Vero cells (ATCC CCL-81) and MSCs obtained from sheep bone marrow using methylthiazol tetrazolium (MTT) and propidium iodide (PI) assays were evaluated. The biomaterial group demonstrated an absence of cytotoxicity, similar to the control group. Samples with 50% and 10% biomaterial extract concentrations showed higher cell viability compared to samples from the control group (MTT assay). These results suggest that the presence of this composite biomaterial can be used with MSCs. This study also concluded that hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were not cytotoxic. Therefore, these could be used for performing in vivo tests.(AU)

O compósito à base de hidroxiapatita, quitosana e nanotubo de carbono foi desenvolvido com o intuito de auxiliar na consolidação óssea. Estudos anteriores sugerem que a combinação de substitutos ósseos e células-tronco mesenquimais (CTM) podem auxiliar a potencializar e promover a regeneração óssea. No presente estudo, o biomaterial foi desenvolvido e a viabilidade e a citotoxicidade de células Vero (ATCC CCL-81) e CTM obtidas de medula óssea provenientes de ovinos utilizando ensaios metil-tiazol-tetrazólio, MTT e iodeto de propídeo (PI) foram avaliadas em diferentes concentrações de extrato desse compósito. O compósito demonstrou ausência de citotoxicidade com comportamento semelhante ao grupo controle. Amostras com 50% e 10% de concentração de extrato do compósito mostraram resultados maiores comparados ao grupo controle (ensaio MTT). Esses resultados também sugerem que a presença do biomaterial pode ser utilizada em associação a CTM. Assim, esse estudo conclui que o compósito apresentado de hidroxiapatita, quitosana e nanotubo de cabono não foi considerado citotóxico e pode ser utilizado em teste in vivo.(AU)

Copaiba oil-resin (Copaifera langsdorfii Desf: Caesalpiniaceae) associated with laser therapy for skin wound treatment in Wistar rats / Óleo resina de copaíba (Copaifera langsdorfii Desf: Caesalpiniaceae) associada a laserterapia para o tratamento de feridas cutâneas em ratos Wistar

Alternative protocols for the treatment of skin lesions have been developed with the use of techniques such as photobiomodulation and phytotherapy, aiming to optimize this process. To evaluate the effectiveness of copaiba (Copaiferalangsdorffii) oil-resin and low-level laser therapy for treating cutaneous wounds, 15 Wistar rats (Rattusnorvergicus) were used, in whom five 8-mm lesions were produced. The following protocols were applied: negative control group (T1); positive control group (T2); laser therapy with AsGa (904 nm), continuous, focal mode for 10 s, dosage of 4 J/cm² (T3); copaiba oil-resin (T4); and association group (copaiba and low-level laser) (T5). The efficacy of each technique was evaluated based on macroscopic aspects of the lesion, wound healing rate, and histopathological analysis (inflammatory infiltrate and collagen expression). The Kruskal-Wallis test was used for statistical analyses (P> 0.05). Copaiba treatment showed an advantage in type III collagen expression, whereas laser therapy demonstrated an enhanced capacity for tissue regeneration. The significant advantage obtained from the association treatment is the improvement of the macroscopic aspect of the wound, with a reduction in crust formation.

Protocolos alternativos para o tratamento de feridas cutâneas têm sido desenvolvidos com a utilização de técnicas como a fotobiomodulação e fitoterapia, objetivando acelerar esse processo. Com o objetivo de avaliar a efetividade do óleo--resina de copaíba (Copaifera langsdorffii) e do laser terapêutico no tratamento de feridas cutâneas foram selecionados 15 ratos Wistar (Rattus norvergicus), nos quais foram produzidas cinco lesões cutâneas de 8mm. Os tratamentos empregados foram: controle negativo (T1); controle positivo (T2); laserterapia com AsGa (9,04nm) no modo contínuo, de maneira focal, com duração de 10 segundos e dosimetria de 4 J/cm² (T3); óleo resina de copaiba (T4) e a associação dos tratamentos (copaiba e laserterapia) (T5). A eficácia de cada técnica foi avaliada com base nos aspectos macroscópicos das lesões, taxa de cicatriza-ção e análise histopatológica (infiltrado inflamatório e expressão do colágeno). Os dados obtidos foram analisados pelo teste de Kruskal-Wallis (P>0,05). O tratamento com a copaíba mostrou vantagem na expressão do colágeno tipo III, enquanto a laserterapia demonstrou aumento da capacidade de regeneração tecidual. A vantagem significativa obtida pela associação dos tratamentos foi a melhora do aspecto macroscópico da ferida, com redução na formação de crostas.