Orange juice containing Pediococcus acidilactici CE51 modulates the intestinal microbiota and reduces induced inflammation in a murine model of colitis.

The management of inflammatory bowel diseases has been widely investigated, especially ulcerative colitis. Thus, studies with the application of new probiotic products are needed in the prevention/treatment of these clinical conditions. The objective of this work was to evaluate the effects of probiotic orange juice containing Pediococcus acidilactici CE51 in a murine model of colitis. 45 male Swiss lineage mice were used, divided into five groups (n = 9): control, colitis, colitis + probiotic (probiotic orange juice containing CE51), colitis + placebo (orange juice) and colitis + sulfasalazine (10 mg/kg/Weight). The induction of colitis was performed with dextran sodium sulfate (3%). The treatment time was 5 and 15 days after induction. Histopathological analysis, serum measurements of TNF-α and C-reactive protein and metagenomic analysis of feces were performed after euthanasia. Probiotic treatment reduced inflammation in the small intestine, large intestine and spleen. The probiotic did not alter the serum dosages of TNF-α and C-reactive protein. Their use maintained the quantitative ratio of the phylum Firmicutes/Bacteroidetes and increased Lactobacillus helveticus with 15 days of treatment (p < 0.05). The probiotic orange juice containing P. acidilactici CE51 positively modulated the gut microbiota composition and attenuated the inflammation induced in colitis.

Analysis of the effects of curcumin and symbiotic consumption on bones of rats submitted to the use of dexamethasone.

AIMS: Glucocorticoids have adverse side effects that can compromise bone tissue. There is evidence to show that symbiotics and curcumin can prevent bone loss. The aim of this study was to analyze the effects of curcumin and symbiotic to prevent and/or minimize a possible bone impairment in rats submitted to the use of dexamethasone. METHODS: Fifty Wistar female rats were divided into five groups: control group (CT), dexamethasone control group (D), dexamethasone and symbiotic group (DS), dexamethasone and curcumin group (DC), and dexamethasone and symbiotic/curcumin group (DSC). Dexamethasone was applied three times a week, while the symbiotic and curcumin were administered daily. Alkaline phosphatase and calcium dosages, analysis of structural and material properties, and Raman analysis of femurs were performed. KEY FINDINGS: Alkaline phosphatase was higher in the DC group. Maximum load and structural stiffness were higher in the CT group. Maximum stress was lower and similar between dexamethasone groups. The CT group had a lower percentage of strain, the D group had greater deformation compared to the DC group and the DS group presented more deformation than the DC group. The D, DS, and DSC groups had a lower elastic modulus compared to the CT group. The 960/1660 ratios of the D, DS, and DSC groups were different from the CT group. The 1070/1660 ratio was higher in the DC group. SIGNIFICANCE: It was possible to verify that curcumin showed promising effects related to the increase in bone strength and mineralization, mitigating the deleterious effects caused by dexamethasone, when used simultaneously with this drug.

Virulence, biofilm formation ability and antimicrobial resistance of staphylococcus aureus isolated from cell phones of university students / Virulência, capacidade de formação de biofilme e resistência antimicrobiana de staphylococcus aureus isolado de telefones celulares de estudantes universitários

INTRODUCTION: Contamination of cell phones can contribute to the dissemination of pathogens in the community and/or hospital environment. OBJECTIVE: To characterize Staphylococcus aureus strains isolated from cell phones of university students. METHODS: Samples were collected from 100 cell phones. Detection of genes associated with virulence factors such as biofilm formation (icaA and icaD), enterotoxins production (SEA, SEB, SEC, and SED), and resistance to methicillin (mecA and mecC) was performed in S. aureus isolates by PCR. Typing mecA gene performed by multiplex PCR. Susceptibility to antimicrobials and biofilm formation rate also evaluated by using disk diffusion test and crystal violet staining. RESULTS: S. aureus was present in 40% of the total samples and about 70% of them belonged to Nursing students. Of the isolates, 85% presented resistance to penicillin and 50% were classified as moderate biofilm producers. In addition, 92.5% of isolates contained the gene icaA and 60% of the gene icaD. Approximately 25% of the isolates presented the mecA gene. Typing of the mecA gene showed the presence of staphylococcal chromosome cassette SCCmec I and c III respectively in 20% and 10% of the isolates. 70% of the samples could not be typed by the technique. Regarding the enterotoxins, the most prevalent gene was SEA (30%) followed by the SEC gene (2.5%). The presence of SED and SEB genes not observed in any of the isolates. CONCLUSION: The cleaning and periodic disinfection of cell phones can contribute to the reduction of the risk of nosocomial infection.

INTRODUÇÃO: A contaminação de celulares pode contribuir para a disseminação de patógenos na comunidade e/ou ambiente hospitalar. OBJETIVO: Caracterizar cepas de Staphylococcus aureus de telefones celulares de estudantes universitários. MÉTODOS: Foram coletadas amostras de 100 telefones celulares. Detecção de genes associados a fatores de virulência quanto a: formação de biofilme (icaA e icaD), produção de enterotoxinas (SEA, SEB, SEC e SED) e resistência à meticilina (mecA e mecC) foi realizada em isolados de S. aureus por PCR. A Tipagem do gene mecA foi realizada por PCR multiplex. A susceptibilidade a antimicrobianos e a taxa de formação de biofilme pelo teste de difusão em disco e coloração com cristal violeta. RESULTADOS: S. aureus esteve presente em 40% do total de amostras, destas, 70% pertenciam a estudantes do curso de enfermagem. Dos isolados, 85% apresentaram resistência à penicilina e 50% foram classificados com moderada formação de biofilme. Além disso, 92,5% dos isolados continham o gene icaA e 60% o gene icaD. Aproximadamente 25% dos isolados apresentaram o gene mecA. A tipagem do gene mecA mostrou a presença do cassete cromossômico estafilocócico SSCmec I e III em respectivamente 20% e 10% dos isolados. 70% das amostras não puderam ser identificadas pela técnica. Das enterotoxinas, o gene mais prevalente foi o SEA (30%), seguido pelo gene SEC (2.5%). A presença dos genes SED e SEB não foi observada nos isolados. CONCLUSÃO: A limpeza e desinfecção periódica dos telefones celulares podem contribuir para a redução do risco de infecção nosocomiais.

Effects of low-intensity pulsed ultrasound exposure on rats tibia periosteum.

The periosteum is a rich source of osteoprogenitor cells and periosteal grafts can be used as an alternative method to replace bone grafts. The low-intensity pulsed ultrasound (LIPUS) has often been used as a noninvasive method to stimulate osteogenesis and reduce the fracture healing time. The aim of this study was to evaluate the effects of the ultrasound exposure on the rat tibia periosteum. Group I (7 animals) received LIPUS therapy on the left tibia for 7 days and group II (7 animals) on the left tibia for 14 days. After euthanasia, the tibias were processed. Number of periosteal cells and vessels and thickness of the periosteum were analyzed. The number of periosteal cells was higher in stimulated periosteum compared to controls at 7 and 14 days, but the number of vessels and the thickness only were higher in the group stimulated at 14 days. Furthermore, the ultrasound treatment for 14 days was more effective than 7 days. The ultrasound stimulation of the periosteum prior to grafting procedure can be advantageous, since it increases periosteal activity, and LIPUS may be an alternative method for stimulating the periosteum when the use of periosteal grafts in bone repair is needed.

Effects of consumption of contaminated feed with 2,4-dichlorophenoxyacetic acid (2,4-D) on the rat tibia: analysis by Raman spectroscopy and mechanical properties.

Studies reported the harmful effects of 2,4-D on body tissues, provoking changes in the anatomy and physiology of the kidneys, liver, and testicles. Thus, the objective was to evaluate if there were alterations in the bone quality of the tibia of rats submitted to feed consumption that were exposed to three different 2,4-D doses. Male Wistar rats were divided into four groups: oral control group (C: feed consumption without 2,4-D contamination); low oral concentration group (G3: contaminated feed with low concentration of 2,4-D); medium concentration group (G6: contaminated feed with medium concentration of 2,4-D); and high concentration group (G9: contaminated feed with high concentration of 2,4-D). The results demonstrated alterations of the mechanical properties and Raman ratios of the tibias of the contaminated groups. The maximum load, maximum stress, elastic modulus, and the cortical area were lower in the G6 and G9 compared to C group. The mineral-to-matrix ratio (relative mineral to organic content) was lower in the G6 and G9 groups compared to C group, but carbonate-to-matrix ratio (indicator of bone turnover) was higher in both groups. Thus, it is possible to suggest that the 2,4-D herbicide performed deleterious effects on the bone quality of male Wistar rats.

Resistance training minimizes the biomechanical effects of aging in three different rat tendons.

Aging process is characterized by a decline in the organism functionality, especially in the decrease of muscle function, which also affects tendons. On the other hand, the resistance training (RT) has been used as an important tool to increase muscle and tendineous function during aging. Thus, this study aim has been to verify the effects of RT on the biomechanical properties of three different aged rat tendons. For this purpose, 20 wistar rats have been divided into four groups (5 rats per group): young sedentary (YS), trained (YT), old sedentary (OS) and old trained (OT). The RT has been performed through climb protocol for 12 weeks. After RT, the calcaneal tendon (CT), superficial flexor tendon (SFT) and deep flexor tendon (DFT) have been used for analysis. The results indicate that the RT in aged rats can prevent tendon function decrease (p<0.05). Although RT has prompted significant biomechanical changes in trained aged rats, there has been no increase in cross-section area or tendon stiffness reduction. Thus, the OT group showed better biomechanical responses when compared with OS (p<0.05). Therefore, RT can be used as an excellent strategy for increasing in tendon capacity during aging.

Biochemical and morphological alterations of the extracellular matrix of chicken calcaneal tendon during maturation.

The region in tendons that surrounds bone extremities adapts to compression forces, developing a fibrocartilaginous structure. During maturation, changes occur in the amount and organization of macromolecules of the extracellular matrix of tendons, changing the tissue morphology. To study the effect of maturation on tendons, Pedrês chickens were sacrificed at 1, 5, and 8 months old and had the calcaneal tendon (CT) divided into proximal region, submitted to tension/compression forces (p), and distal region submitted to tension force (d). Morphological analysis of the p region showed the presence of fibrocartilage in all ages. In the central part of the fibrocartilage, near a diminishment of the metachromasy, there was also a development of a probable fat pad that increased with the maturation. The activity of MMP-2 and MMP-9 was higher at 5 and 8 months old, in both regions, compared with 1-month-old animals. In SDS-PAGE analysis, components with electrophoretic migration similar to decorin and fibromodulin increased with maturation, particularly in the d region. The Western blotting confirmed the increased amount of fibromodulin with maturation. In conclusion, our results show that process of maturation leads to the appearance of a probable fat pad in the center of the fibrocartilage of CT, with a reduced amount of glycosaminoglycans and an increased activity of MMPs.

Metabolic and structural bone disturbances induced by hyperlipidic diet in mice treated with simvastatin.

Simvastatin can modulate lipid and bone metabolism. However, information related to the interaction between diet and simvastatin on bone structure and biomechanics is scarce. Thus, this study evaluated the effects of simvastatin on femoral biomechanics and cortical/trabecular bone structure in wild-type mice nourished with a hyperlipidic diet. Three-month-old male wild-type mice (C57BL6 strain) were divided into four groups: (1) group W, nourished with a standard diet; (2) group WH, fed a hyperlipidic diet; (3) group WS, nourished with a standard diet plus oral simvastatin (20 mg/kg/day); and (4) group WHS, fed a hyperlipidic diet plus oral simvastatin (20 mg/kg/day). All animals received only their specific diet and water for 60 days. Blood samples were collected for the analysis of calcium, triglycerides, total cholesterol (TC) and fraction serum levels. Diet manipulation was able to induce a dyslipidaemic status in mice, characterized by triglyceride and TC rise in WH animals. Simvastatin prevented hypercholesterolaemia and reduced TC and LDL serum levels, but did not prevent hypertriglyceridaemia and HDL serum levels in the WHS group. In the WH mice the hyperlipidaemia was associated with reduction in trabecular bone thickness, femur structural and material property alterations. Simvastatin prevented these morphological alterations and minimized femur biomechanical changes in WHS mice. Taken together, the results indicated that the hyperlipidic diet intake acts as a risk factor for bone integrity, generating bones with reduced resistance and more susceptible to fractures, an effect attenuated by simvastatin that is potentially related to the modulatory action of this drug on lipid and bone metabolism.

Biochemical and morphological alterations in the Achilles tendon of mdx mice.

Dystrophin-deficient muscles have repeated cycles of necrosis and regeneration, being susceptible to injury induced by muscle contractions. Some studies have demonstrated that tendons are also affected in mdx mice, based especially on the changes in biomechanical properties arising from the respective linked muscles. However, most studies have focused only on alterations in the myotendinous junction. Thus, the purpose of this work was to study biochemical and morphological alterations in the Achilles tendons of 60-day-old mdx mice. Hydroxyproline quantification, showed higher collagen concentration in the mdx mice as compared with the control. No difference between the tendons of both groups was found in the noncollagenous proteins dosage, and in the amount of collagen type III detected in the western blotting analysis. The zymography for gelatinases detection showed higher amounts of metaloproteinase-2 (active isoform) and of metalloproteinase-9 (latent isoform) in the mdx mice. Measurements of birefringence, using polarization microscopy, showed higher molecular organization of the collagen fibers in the tendons of mdx mice in comparison to the control group, with presence of larger areas of crimp. Ponceau SS-stained tendon sections showed stronger staining of the extracellular matrix in the mdx groups. Toluidine blue-stained sections showed more intense basophilia in tendons of the control group. In morphometry, a higher number of inflammatory cells was detected in the epitendon of mdx group. In conclusion, the Achilles tendon of 60-day-old mdx mice presents higher collagen concentration and organization of the collagen fibers, enhanced metalloproteinase-2 activity, as well as prominent presence of inflammatory cells and lesser proteoglycans.

Mechanical and morphological aspects of the calcaneal tendon of mdx mice at 21 days of age.

A relationship between compromised muscles and other tissues has been demonstrated in mdx mouse, an animal model studied for understanding of Duchenne muscular dystrophy. The hypothesis is that changes in the calcaneal tendon of mdx mice occur previous to the onset of rigorous and most marked episodes of muscle degeneration, which start suddenly after 21 days of life. Thus, this study aimed to identify possible alterations in the calcaneal tendon of mdx mouse at 21 days of age. Control and mdx tendons were submitted to mechanical tensile testing, quantification of hydroxyproline, and staining with toluidine blue and picrosirius red. Hydroxyproline content was similar between mdx and control groups. The control tendon presented higher mechanical strength (load, stress, and elastic modulus) and its morphological analysis showed a larger number of round fibroblasts, nuclei with well-decondensed chromatin, and slightly metachromatic well-stained cytoplasmic material, different from that observed in mdx tendons. The results suggest that the absence of dystrophin in mdx mouse can provoke directly or indirectly alterations in the mechanical properties and morphology of the calcaneal tendon.

Efeito da dexametasona e do cetoprofeno na osteogênese e na resistência óssea em ratos / Effect of dexamethasone and ketoprofen on osteogenesis and bone resistance in rats

O presente estudo teve como objetivo avaliar o efeito do cetoprofeno e da dexametasona na osteogênese ao redor de implante de hidroxiapatita densa (HAD) na tíbia, no osso parietal, e na resistência óssea. Utilizaram-se 15 ratos Wistar, pesando 250±30 g, com 50 dias de idade. Após a anestesia com quetamina/xilazina IM, produziu-se no osso parietal e na epífise proximal da tíbia uma cavidade de 3 mm, sendo implantada a HAD. Após a cirurgia os animais foram divididos em três grupos (n=5): controle (CT), anti-inflamatório não esteroidal (AINES) e anti-inflamatório esteroidal (AIES). O grupo AINES foi submetido ao tratamento com cetoprofeno na dose de 12 mg/Kg/dia, o AIES recebeu doses de 0,10 mg/kg/dia de dexametasona o grupo CT recebeu solução fisiológica 0,9% (SF) por via subcutânea durante 30 dias. Todos os grupos receberam a mesma dieta sólida e água ad libitum. Após 30 dias de experimento os animais sofreram eutanásia, os fêmures coletados, para teste mecânico, e os locais do implante das tíbias e o osso parietal, para análise histomorfométrica. Os grupos AINES e AIES apresentaram menor volume de osso neoformado na falha óssea e ao redor do implante de HAD , como também, menor força máxima para a ruptura completa dos fêmures, quando comparados com o grupo CT. O uso do cetoprofeno e a dexametasona interferiram na osteogênese ao redor do implante de HAD e no osso parietal, diminuindo a resistência óssea principalmente pela inibição da COX2 e diminuição das prostaglandinas, comprometendo a estabilidade e manutenção do implante.

This study aimed at evaluating the effect of ketoprofen (NSAID) and dexamethasone (SAID) on osteogenesis around a dense hydroxyapatite (DHA) implant in the tibia and parietal bone, and on the bone resistance. Fifteen fifty-day-old Wistar rats weighing on average 250±30 g were used. The animals were separated into three groups (n=5): control (CT); non-steroidal anti-inflammatoryl (NSAID); and steroidal anti-inflammatory (SAID). After anesthesia with IM ketamine/xylazine, a 3 mm cavity was made in the left parietal bone and in the proximal epiphysis of the left tibia. A DHA bioceramic was implanted in the tibia. The animals were treated subcutaneously during 30 days as follows: NSAID group: ketoprofen at the dose of 12/Kg/day; SAID group: dexamethasone, 0,10 mg/kg/day. The CT group received saline through the same route. All the animals received the same solid diet and water ad libitum. After 30 days of experiment, the animals wereeuthanized, and their femurs collected for the mechanical test, while their tibia and parietal sites were prepared for the histomorphometrical analysis. Microscopically, the SAID and NSAID groups showed a lower volume of neoformed bone. In addition, the NSAID and SAID group femurs required lower maximum force for complete rupture when compared with the CT group. It was concluded that ketoprofen and dexamethasone interfered with osteogenesis and decreased bone resistance by altering the bone tissue metabolism, mainly by inhibiting the COX-2 and decreasing prostaglandins. Therefore, the use of ketoprofen and dexamethasone after bone surgeries can compromise the stability and maintenance of implants.

Effect of hyperlipidemia on femoral biomechanics and morphology in low-density lipoprotein receptor gene knockout mice.

The objective of this study was to evaluate the effect of hyperlipidemia on the biomechanical and morphological properties of the femur of low-density lipoprotein receptor gene knockout mice (LDLr-/-) mice. Ten wild-type mice (C57BL6) and 10 LDLr-/- mice generated on a C57BL6 background were used. Male 3-month-old animals were divided into four groups (n = 5): group W (wild type) and group L (LDLr-/-) receiving low-fat commercial ration, and group WH (wild type) and group LH (LDLr-/-) receiving a high-fat diet. After 60 days, blood samples were collected for laboratory analysis of calcium, triglycerides, and cholesterol. The femur was excised for mechanical testing and morphometric analysis. LDLr-/- mice receiving the high-fat diet presented more marked alterations in the mechanical and morphological properties of femoral cortical and trabecular bone. Changes in the plasma levels of calcium, triglycerides, cholesterol, and fractions were also more pronounced in this group. The present results demonstrate that hyperlipidemia causes alterations in the structure and mechanical properties of the femur of LDLr-/- mice. These effects were more pronounced when associated with a high-fat diet.

Spontaneous healing capacity of calvarial bone defects in mdx mice.

The mdx mouse is an experimental model widely used for the study of Duchenne muscular dystrophy, which is characterized by the lack of dystrophin and cycles of muscle degeneration/regeneration. Studies demonstrated elevated levels of growth factors and accelerated skin wound repair in these animals. We therefore raised the hypothesis that the bone repair process might also be altered in these animals. Thus, the objective of this study was to evaluate the spontaneous healing of calvarial defects in mdx mice by histomorphometric analysis. Animals (45 days old) were divided into mdx and control groups. A defect measuring 2 mm in diameter was produced surgically in the right parietal bone of each animal. The animals were sacrificed 15, 30, and 60 days after surgery, and the skulls were processed by routine histological procedures. No difference in the volume of new bone inside the defect was observed between the two groups at any of the three postoperative time points. There was also no difference between the different periods of healing when each group was analyzed separately. The lower quality of femoral and calvarial bone in mdx mice reported in previous studies and the similar bone regeneration rates seen in two groups suggest that the healing capacity of calvarial defects was more expressive in mdx mice than in control animals. An increase in the amount of osteogenic factors released by damaged myofibers may have favored osteogenesis during bone defect healing in mdx mice.

Bone tissue and muscle dystrophin deficiency in mdx mice.

Duchenne muscular dystrophy is a neuromuscular disease caused by the lack of dystrophin that affects skeletal muscles, causing degeneration of muscle fibers and replacing them with fibrous and adipose tissue, events that gradually lead to functional loss. Patients with Duchenne muscular dystrophy have shown that bones become more fragile with age and with advancement of the disease. Muscle weakness and reduced mobility have been suggested to be the factors that promote bone deterioration. However, it seems that this does not occur in mdx mice. It has been identified in mdx mice the existence of a factor related or not to the lack of dystrophin that also participates in the impairment of bone quality. Mdx mice also exhibit muscle degeneration, but unlike human, it is compensated by muscle regeneration. In consequence, there is an increase in the muscle mass, but not necessarily of muscle contractile strength. The accommodation of this increased muscle mass promotes bone formation at specific sites, such as at tendo-osseous junctions. In addition, the inflammatory response to muscle injury may be responsible for the increase in angiogenesis and regeneration observed in mdx mice, inducing the release of cytokines and chemokines that play an important role in the recruitment of leukocytes and macrophages. Then, mdx mice may possess compensatory mechanisms in bone in response to a genetic defect.

Mechanical, biochemical and morphometric alterations in the femur of mdx mice.

The bone tissue abnormalities observed in patients with Duchenne muscular dystrophy are frequently attributed to muscle weakness. In this condition, bones receive fewer mechanical stimuli, compromising the process of bone modeling. In the present study we hypothesize that other factors inherent to the disease might be associated with bone tissue impairment, irrespective of the presence of muscle impairment. Mdx mice lack dystrophin and present cycles of muscle degeneration/regeneration that become more intense in the third week of life. As observed in humans with muscular dystrophy, bone tissue abnormalities were found in mdx mice during more intense muscle degeneration due to age. Under these circumstances, muscle deficit is probably one of the factors promoting these changes. To test our hypothesis, we investigated the changes that occur in the femur of mdx mice at 21 days of age when muscle damage is still not significant. The mechanical (structural and material) and biochemical properties and morphometric characteristics of the femur of mdx and control animals were evaluated. The results demonstrated a lower strength, stiffness and energy absorption capacity in mdx femurs. Higher values for structural (load and stiffness) and material (stress, elastic modulus and toughness) properties were observed in the control group. Mdx femurs were shorter and were characterized by a smaller cortical area and thickness and a smaller area of epiphyseal trabecular bone. The hydroxyproline content was similar in the two groups, but there was a significant difference in the Ca/P ratios. Thermogravimetry showed a higher mineral matrix content in cortical bone of control animals. In conclusion, femurs of mdx mice presented impaired mechanical and biochemical properties as well as changes in collagen organization in the extracellular matrix. Thus, mdx mice developed femoral osteopenia even in the absence of significant muscle fiber degeneration. This weakness of the mdx femur is probably due to genetic factors that are directly or indirectly related to dystrophin deficiency.

Efeitos do fenobarbital sobre o reparo e a biomecânica de ossos em ratos Wi star / Effects of phenobarbital on bone repair and biomechanics in rats

OBJETIVO: Avaliar os efeitos morfológicos do tratamento com fenobarbital, sobre a neoformação óssea e sobre a biomecânica óssea do osso de ratos Wistar. MÉTODOS: Foram utilizados dez ratos divididos em dois grupos: controle (CT) e fenobarbital (FE). O grupo FE recebeu doses diárias de fenobarbital 0,035 ml/kg via intramuscular, por 60 dias. O grupo CT recebeu a mesma dose e via de administração de solução fisiológica 0,9 por cento. Após 30 dias, foi realizada uma falha óssea no osso parietal e implantada a hidroxiapatita porosa (HAP) em cavidades nas tíbias. Após as cirurgias, manteve os respectivos protocolos até completar 60 dias e serem eutanasiados, sendo os ossos coletados. RESULTADOS: O volume de osso formado ao redor HAP na falha parietal e os achados biomecânicos foram menores nos animais do grupo FE em relação ao CT. CONCLUSÃO: O uso prolongado do fenobarbital interfere no reparo ósseo após lesões, diminui a osseointegração de implantes de HAP e torna os ossos menos resistentes.

OBJECTIVE: To evaluate the morphological effects of phenobarbital treatment on new bone formation and on bone marrow biomechanics in Wistar rats. METHODS: We used ten rats that were divided into two groups: control (CT) and phenobarbital (FE). The FE group received daily doses of phenobarbital 0.035 ml / kg intramuscularly for 60 days. The CT group received the same dose and route of administration of 0.9 percent saline solution. After 30 days, we introduced a bone defect in the parietal bone and implanted porous hydroxyapatite (HAP) in cavities in the tibia. After surgery, we continued the protocols until the end of 60 days when the rats were euthanized, and the bones were collected. RESULTS: The volume of bone formed around HAP in parietal defect and biomechanical findings were lower in animals receiving FE compared to CT. CONCLUSION: Prolonged use of phenobarbital interferes with bone repair after injury, decreasing the osseointegration of HAP implants and making bones less resistant.

OBJETIVO: Evaluar los efectos morfológicos del tratamiento con fenobarbital, sobre la neoformación ósea y sobre la biomecánica ósea del hueso de ratas Wistar. MÉTODOS: Fueron utilizadas diez ratas divididas en dos grupos: control (CT) y fenobarbital (FE). El grupo FE recibió dosis diarias de fenobarbital 0,035 ml/kg vía intramuscular, por 60 días. El grupo CT recibió la misma dosis y vía de administración de solución fisiológica 0,9 por ciento. Después de 30 días, se realizó una falla ósea en el hueso parietal e implantó la hidroxiapatita porosa (HAP) en cavidades en las tibias. Después de las cirugías, se mantuvo los respectivos protocolos hasta completar 60 días y de ser eutanasiados, siendo recolectados los huesos. RESULTADOS: El volumen de hueso formado alrededor HAP en la falla parietal y los hallazgos biomecánicos fueron menores en los animales del grupo FE en relación al CT. CONCLUSIÓN: El uso prolongado del fenobarbital interfiere en la reparación ósea después de lesiones, disminuye la óseointegración de implantes de HAP y vuelve a los huesos menos resistentes.

Efeitos do alcoolismo e da desintoxicação alcoólica sobre o reparo e biomecânica óssea / Effects of alcoholism and alcoholic detoxication on the repair and biomechanics of bone

OBJETIVO: Avaliar os efeitos do consumo crônico de etanol e da desintoxicação alcoólica sobre a resistência mecânica do osso e neoformação óssea junto a implantes de hidroxiapatita densa (HAD) realizados em ratos. MÉTODOS: Foram utilizados 15 ratos divididos em três grupos, sendo controle (CT), alcoolista crônico (AC) e desintoxicado (DE). Após quatro semanas, foi realizada implantação de HAD na tíbia e produzida falha no osso parietal, em seguida o grupo AC continuaram a consumir etanol e o grupo DE iniciaram a desintoxicação. Ao completar 13 semanas os animais sofreram eutanásia, os ossos foram coletados para o processamento histomorfométrico e os fêmures encaminhados ao teste mecânico de resistência. RESULTADOS: Os animais do grupo AC apresentaram menores valores de neoformação óssea, de calcemia e resistência mecânica, quando comparado aos grupos CT e DE. Os animais dos grupos DE apresentaram valores superiores em todas as variáveis avaliadas em relação ao grupo AC. CONCLUSÃO: O consumo de etanol interferiu na osteogênese ao redor de implante de HAD, nos níveis de cálcio e na resistência mecânica óssea. A desintoxicação alcoólica se mostrou eficaz, pois aumentou à osteogênese e osseointegração da HAD, a calcemia e resistência mecânica óssea. Nivel de Evidência I, estudo terapeutico.

OBJECTIVE: To evaluate the effects of chronic ethanol consumption and alcohol detoxication on the mechanical resistance of bone and bone neoformation around dense hydroxyapatite implants (DHA) in rats. METHODS: Fifteen rats were separated into three groups: (1) control group (CT); (2) chronic alcoholic (CA), and (3) disintoxicated (DI). After four weeks, a DHA was implanted in the right tibia of the animals, and the CA group continued consuming ethanol, while the DI group started detoxication. The solid and liquid feeding of the animals was recorded, and a new alcohol dilution was effected every 48 hours. After 13 weeks, the animals were euthanized and their biological material was collected. RESULTS: Bone tissue was found around DHA in all the animals. Group CA showed less bone neoformation, lower levels of ionic and total calcium when compared to the animals of the CT and DI groups. The DI animals showed higher values in all the variables in relation to the CA group. CONCLUSION: Ethanol consumption interfered in osteogenesis around the DHA implants, and in calcium levels and mechanical bone resistance. Alcohol detoxication was effective, as it increased osteogenesis, DHA osteointegration, calcemia, and mechanical resistance of the bone. Level of Evidence: Level I, therapeutic studies.

Effects of passive stretching on the biochemical and biomechanical properties of calcaneal tendon of rats.

The role of physical activity in affecting the composition of extracellular matrix and mechanical properties of tendons has been well studied, but little is known about the role of passive stretching. The purpose of this study was to test the hypothesis that stimulation by passive stretching may change the composition and mechanical properties of tendons. Three-month-old Wistar rats were divided into three groups: the control, animals were not submitted to stretching procedures; groups that had their calcaneal tendons manually stretched three or five times a week, for 21 days. Afterward, the calcaneal tendons were removed and assayed for hydroxyproline content and biomechanical test. The hydroxyproline content in the stretched groups was higher, suggesting that more collagen was present in the tendons of these groups. These tendons also showed higher values of maximum stress and modulus of elasticity or Young's modulus. These results indicate that stretching leads to alterations in the synthesis of the extracellular matrix components and in the mechanical properties of tendons.

Organization of collagen bundles during tendon healing in rats treated with L-NAME.

The Achilles tendon can support high tension forces and may experience lesions. The damaged tissue does not regenerate completely, with the organization and mechanical properties of the repaired tendon being inferior to those of a healthy tendon. Nitric oxide (NO) plays an important role in wound repair. We have examined the structural reorganization and repair in Achilles tendon after injury in rats treated with the NO synthase inhibitor L-NAME. The right Achilles tendon of male Wistar rats was partially transected. One group of rats was treated with L-NAME (~300 mg/kg per day, given in drinking water) for 4 days prior to tendon sectioning and throughout the post-operative period. Control rats received water without L-NAME. The tendons were excised at 7, 14, and 21 days post-injury and used to quantify hydroxyproline and for mechanical tests. Tendons were also processed for histomorphological analysis by polarized light microscopy, which showed that the collagen fibers were disorganized by day 7 in non-treated and L-NAME-treated rats. In non-treated rats, the organization of the extracellular matrix was more homogeneous by days 14 and 21 compared with day 7, although this homogeneity was less than that in normal tendon. In contrast, in injured tendons from L-NAME-treated rats, the collagen fibers were still disorganized on day 21. Tendons from treated rats had more hydroxyproline but lower mechanical properties compared with those from non-treated rats. Thus, NO modulates tendon healing, with a reduction in NO biosynthesis delaying reorganization of the extracellular matrix, especially collagen.

Biomechanical and biochemical properties of chicken calcaneal tendon under effect of age and nonforced active exercise.

This study investigated if nonforced active exercise alters the biomechanical and biochemical properties of calcaneal tendon during maturation. Chickens at 1, 5, and 8 months old were divided into two groups: caged and penned. Intact tendons were used for biomechanical analysis, but they were divided into tensile and compressive regions for quantification of hydroxyproline and glycosaminoglycans. The exercise increased tendon strength after the fifth month, energy absorption in the eighth month, and ultimate tensile stress in the first month. Age increased tendon strength and energy storage and reduced stiffness but did not alter stress. There was an increase in collagen content in the fifth month. Glycosaminoglycans showed a progressive decline in the tensile region. Thus, some biomechanical and biochemical changes depend on the maturation process itself and also are influenced by spontaneous exercise, showing that mechanical stimulation of low intensity may help to improve the quality of the tendon.