Effects of ethanol consumption and alcohol detoxification on the biomechanics and morphology the bone in rat femurs.

The objective of this study was to verify the effects of ethanol consumption and alcohol detoxification on the biomechanics, area and thickness of cortical and trabecular bone in rat femur. This was an experimental study in which 18 male Wistar rats were used, with 40 days of age, weighing 179 ± 2.5 g. The rats were divided into three groups (n=06): CT (control), AC (chronic alcoholic), DT (detoxification). After experimental procedures, the animals were euthanized by an overdose of the anesthetic and their femurs were collected for mechanical testing and histological processing. All animals did not present malnutrition or dehydration during experimentation period. Morphometric analysis of cortical and trabecular bones in rat femurs demonstrated that AC animals showed inferior dimensions and alcohol detoxification (DT) allowed an enhancement in area and thickness of cortical and trabecular bone. Material and structural properties data of AC group highlighted the harmful effects of ethanol on bone mechanical properties. The results of this study demonstrated that chronic alcoholic rats (AC) presented major bone damage in all analyzed variables. Those findings suggested that alcohol detoxification is highly suggested in pre-operative planning and this corroborates to the success of bone surgery and bone tissue repair. Thanks to the financial support offered by PROBIC - UNIFENAS.

Effects of ethanol consumption and alcohol detoxification on the biomechanics and morphology the bone in rat femurs / Efeitos do consumo de etanol e da desintoxicação alcóolica sobre a biomecânica e morfologia óssea em fêmur de ratos

Abstract The objective of this study was to verify the effects of ethanol consumption and alcohol detoxification on the biomechanics, area and thickness of cortical and trabecular bone in rat femur. This was an experimental study in which 18 male Wistar rats were used, with 40 days of age, weighing 179±2.5 g. The rats were divided into three groups (n=06): CT (control), AC (chronic alcoholic), DT (detoxification). After experimental procedures, the animals were euthanized by an overdose of the anesthetic and their femurs were collected for mechanical testing and histological processing. All animals did not present malnutrition or dehydration during experimentation period. Morphometric analysis of cortical and trabecular bones in rat femurs demonstrated that AC animals showed inferior dimensions and alcohol detoxification (DT) allowed an enhancement in area and thickness of cortical and trabecular bone. Material and structural properties data of AC group highlighted the harmful effects of ethanol on bone mechanical properties. The results of this study demonstrated that chronic alcoholic rats (AC) presented major bone damage in all analyzed variables. Those findings suggested that alcohol detoxification is highly suggested in pre-operative planning and this corroborates to the success of bone surgery and bone tissue repair. Thanks to the financial support offered by PROBIC – UNIFENAS.

Resumo O objetivo deste estudo foi verificar os efeitos do consumo de etanol e da desintoxicação alcoólica sobre a biomecânica, área e espessura do osso cortical e trabecular em fêmur de ratos. Este foi um estudo experimental no qual foram utilizados 18 ratos Wistar machos, com 40 dias de vida, pesando 179±2,5 g. Os ratos foram divididos em três grupos (n=06): CT (controle), AC (alcoolista crônico), e DT (desintoxicado). Após os procedimentos experimentais os animais foram eutanaziados por uma overdose de anestésico e os fêmures coletados para os testes mecânicos e processamento histológico. Todos os animais não apresentaram desnutrição ou desidratação durante o período de experimentação. As análises morfométrica do osso cortical e trabecular demonstraram que os animais do grupo AC apresentavam dimensões inferiores, enquanto nos animais do grupo DT observou-se um aumento na área e espessura do osso cortical e trabecular. Dados dos materiais e das propriedades estruturais óssea do grupo AC destacam os efeitos nocivos do etanol sobre as propriedades mecânicas do osso. Os resultados deste estudo demonstraram que os ratos do grupo AC apresentaram danos significativos no osso em todas as variáveis ​​analisadas. Esses resultados sugerem que a desintoxicação alcoólica é recomendada no planejamento pré-operatório e isso corrobora para o sucesso de cirurgias e reparação no tecido ósseo. Agradecemos ao apoio financeiro oferecido pelo PROBIC – UNIFENAS.

Efeitos da fumaça de cigarro sobre a osteogênese e a resistência mecânica óssea em ratos / Effects of cigarette smoke on osteogenesis and bone mechanical resistance in rats

This paper reports a study of the effects of exposure to cigarette smoke on osteogenesis and the mechanical strength of bone in rats. Twelve male rats were separated into two groups (n=6): CT (control) and CI (cigarette). All the animals had free access to rat chow and water throughout the experiment. Group CI was exposed to the smoke of 6 cigarettes/day for 12 weeks. After 6 weeks of exposure to cigarette smoke, a defect was produced on the parietal bone and dense hydroxyapatite (DHA) ceramic bodies were implanted into cavities made surgically in the tibia of the animals, in each group. After surgery, the CT and CI groups returned to normal experimental conditions and, at the end of 12 weeks, they were euthanized, and their tibiae and parietal bones removed for histological processing, while the femurs were subjected to biomechanical tests in a MTS TestStar II three-point flexion module. Consumption of solid and liquid diet was satisfactory in both groups, all animals gaining weight throughout the experiment. CI animals showed a smaller volume of newly formed bone in the parietal defect (8.l9±0.2) and around the DHA implant in the tibia (33±0.5) than the rats in the CT group (14.4±0.5 and 39±1 respectively). The maximum force needed to break the femur was smaller in CI (119±3.2) than in CT (140±6.5). The results of this study led to the conclusion that exposure to cigarette smoke interfered with osteogenesis in the bone defect and around the DHA implant and reduced the maximum force required to completely break the femur, revealing that bone fragility can be caused by tobacco smoke.

O presente estudo teve como objetivo avaliar os efeitos da exposição à fumaça de cigarro sobre a osteogênese e a resistência mecânica do osso em ratos. Foram utilizados doze ratos machos, divididos em dois grupos (n=6): grupo CT (controle) e grupo CI (cigarro). Durante 12 semanas, os animais do grupo CI foram expostos à fumaça de seis cigarros/dia. Após seis semanas de exposição à fumaça de cigarro, uma falha óssea de 5mm foi produzida no osso parietal e corpos cerâmicos de hidroxiapatita densa (HAD) foram implantados em cavidade produzida cirurgicamente na tíbia dos animais do grupo CI e CT. Após as cirurgias, os animais retornaram aos protocolos experimentais e, ao término de doze semanas de experimentação, foram eutanasiados, as tíbias e os ossos parietais foram coletados para processamento histológico e os fêmures encaminhados para ensaio biomecânico em um módulo MTS TestStar II®. A exposição à fumaça do cigarro não interferiu no ganho de peso dos animais e os consumos de dieta líquida e sólida foram satisfatórios entre os grupos. Os animais do grupo CI apresentaram menor volume de osso neoformado na falha óssea (8,9±0,2) produzida no osso parietal e ao redor do implante de HAD na tíbia (33±0,5). A força máxima necessária para romper o fêmur dos animais foi menor no grupo CI (119±3,2) do que no grupo CT (140±6,5). Com bases nos resultados obtidos no presente trabalho, pôde-se concluir que a exposição à fumaça do cigarro interferiu na osteogênese da falha óssea e ao redor do implante de HAD, diminuiu a força máxima necessária para a ruptura completa dos fêmures e demonstrando a fragilidade óssea causada pelo hábito tabagista.

Effects of ethanol on the osteogenesis around porous hydroxyapatite implants.

Alcohol consumption compromises bone tissue, and thus may either impair or stop the fixation and maintenance of osseointegrated implants. To evaluate the effects of 5% and 15% ethanol on bone neoformation around porous hydroxiapatite implants. Fifteen rats were separated into 3 groups of 5 animals each: control (CT); 5% alcohol (A); and 15% alcohol (AA). After four weeks of ethanol consumption, the rats received porous hydroxiapatite implants into surgically made cavities in the femur. After surgery, the animals continued to consume ethanol until day 90 of the experiment, when they were euthanised and their femurs removed for histological processing. Bone tissue was found around the ceramic specimens of all the animals. The largest volume of neoformed bone around ceramic specimens occurred in the CT group, and the smallest in the AA group, followed by the A group. It was concluded that ethanol consumption produced a negative effect on osteogenesis around hydroxyapatite implants. Even small doses, such as the 5% ethanol dilution can interfere with bone repair.

The use of hydroxyapatite and autogenous cancellous bone grafts to repair bone defects in rats.

Bone grafts are frequently used in the treatment of bone defects. Bone harvesting can cause postoperative complications and sometimes does not provide a sufficient quantity of bone. Therefore, synthetic biomaterials have been investigated as an alternative to autogenous bone grafts. The objective of this study was to evaluate the repair of bone defects by autogenous cancellous bone grafts or porous bioceramic discs of hydroxyapatite/phosphate cement mixture. Two 5-mm diameter defects were made in the skulls of rats and filled with the bioceramic material or cancellous bone. The rats were sacrificed 2, 4, 8 and 24 weeks after surgery and tissue samples were analyzed by radiography and histology. By the 24th week, the defects filled with autogenous cancellous bone grafts or bioceramic material showed similar volumes of bone tissue within the defect. However, defects treated with bioceramic material were almost completely closed as a result of the joining of ceramic fragments and the neoformed bone tissue, while those filled with autogenous grafts showed several areas filled with connective tissue. These results indicated that the osteointegration of bioceramic fragments allowed the reconstruction of parietal bone defects without the need for a bone graft.

Behavior of dense and porous hydroxyapatite implants and tissue response in rat femoral defects.

Porous and dense hydroxyapatite cylinders (PHA and DHA) were implanted into cavities produced in rat femora and the sites of implantation were examined at different times over a period of 24 weeks by microradiologic and histological techniques. Microradiographs showed the presence of a layer of trabecular bone around the implants, which became more radiopaque and thinner along the experimental time. The microradiologic methodology used was suitable for the evaluation of the interface between hydroxyapatite and newly formed bone in nondecalcified materials. Microscopic observations showed that young bone grew over the surface of both types of implants after 1 and 2 weeks of surgery and that bone also grew inside PHA implants. Progressive bone absorption was observed in both types of implants after the fourth week. A layer of fibrous tissue was formed in the interface between new bone and DHA. Mature bone with haversian systems surrounded DHA implants and filled the pores of PHA implants throughout the experimental period. The pores of PHA implants were smaller than those commonly reported, which should have been a disadvantage, although it was observed that the extra cellular fluid induced disintegration of the ceramic granules, allowing the gradual growth of bone tissue into the spaces among them, without the interposition of fibrous tissue.

Periosteal donor site regeneration in rats.

Periosteal regeneration was investigated in two periosteal donor sites of the femur. The periosteum was taken from the femur epiphyses and diaphyses of 32 rats. The animals were sacrificed 1, 2, 3, 4 and 8 weeks after periosteal stripping. Intense cell proliferation occurred in the first week. After two weeks, a thick tissue layer formed by osteoblasts and undifferentiated cells was seen at the two donor sites. Eight weeks after, the periosteum had the same aspect as that from the right femur, which was used as control. Histomorphometric analysis showed that periosteal regeneration was significantly different between epiphyses and diaphyses. Periosteal regeneration at donor site located in epiphyses presented greater proliferation and better osteogenic activity than that observed in diaphyses.

On the incidence of the biceps brachii third head in Brazilian white and blacks.

The incidence of a third head of the biceps brachii muscle has been reported in several articles, and there is a general idea that it is a race-dependent variation. The aim of this investigation was to study the biceps brachii muscle with regard to the incidence of its third head in a mixed white and black Brazilian population. A total of 200 upper arms from adult white and black cadavers (100 whites and 100 blacks) fixed in a 10% formol solution were examined and compared. It was observed that for white subjects the incidence of the third head was 20% against 9% for the black subjects: a statistically significant difference. We suggest that other factors, in addition to racial ones, might play a part in determining the incidence of the biceps brachii third head in a population.

Bone formation by vascularized periosteal and osteoperiosteal grafts. An experimental study in rats.

The osteogenic capacity of vascularized periosteal and osteoperiosteal grafts was investigated in 82 Wistar rats about 8 weeks old. The periosteal flaps, pedicled on the descending genicular artery, were taken by stripping the lower third of the femur. In the right hindleg, the grafts were made with periosteum only, while in the left hindleg, the periosteal flaps were associated with cancellous bone. The animals were divided into two groups of 41. In group I, both the periosteal and osteoperiosteal grafts were placed in contact with cortical bone, and in group II, the grafts were buried in muscle. Subgroups of 8 animals were killed after 1, 2, 4, 8, and 16 weeks postoperatively. The grafted region was evaluated radiographically, macroscopically, and histologically. Membranous ossification was the main source of bone formation. Osteoperiosteal grafts produced a greater amount of new bone than periosteal ones. There was evidence that the contact of the graft with living cortical bone favored bone formation.

[Ultrastructure of the boundary tissue of the extratesticular rete and efferent ductules in the cat (Felis domestica, L.)]. / Ultra-estrutura do tecido circundante da rede extratesticular e dos dúctulos eferentes no gato (Felis domestica, L.).

In the cat the boundary tissue of the extratesticular rete testis and efferent ductules is formed by lamellar and fibrillar collagen and elongated contractile cells. These cells are mainly represented by smooth muscle cells and myofibroblasts.

[Morphological study of the heart of Electrophorus electricus]. / L'étude morphologique du coeur du "poraquê" (Electrophorus electricus).

Hearts of 7 Electrophorus electricus have been investigated on macroscopical and microscopical levels. Generally, the structure of the heart exhibits relative similarities with the other studied teleosts. The ventricular myocardium is mainly spongy and suggests that these structural features can offer an additional contraction power.

[The morphological study of the respiratory organ of Electrophorus electricus]. / Contribution à l'étude morphologique de l'organe respiratoire de l'Electrophorus electricus.

The respiratory organ of Electrophorus electricus is located in the oral cavity and is formed by papillar structures. The papilla consists basically of a cartilaginous central nucleus and is bounded by a connective layer. The results reveal structural adaptations for the respiration among fishes which have efficient respiratory circulation related with the venous blood.