Age-related changes in bone architecture / Alterações na estrutura óssea relacionadas à idade

ABSTRACT Objective : to evaluate the histologic and morphometric characteristics of bone biopsies of the anterior iliac crest of patients of different age groups. Methods : we studied 30 bone samples from the iliac crest, using brightfield optical microscopy. We divided the samples by donors' age groups in three groups: Group 1 (n = 10), subjects aged between 25 and 39 years; Group 2 (n = 10), subjects aged between 40 and 64 years; Group 3 (n = 10), individuals aged 65 years and over. We randomly divided the samples into two sets with 15 specimens. In the first study segment (n = 15), we used histological to assess the osteogenic property of the graft, through the analysis of cell reserve in the periosteum, the number of osteocytes in the lacunae and the number of Haversian and Volkmann's canals. In the second study segment (n = 15), we investigated the morphology of osteoconductive property of the graft, through quantification of the trabecular meshwork (Vv) and trabecular area (Sv). Results : histologically, we observed degeneration of bone occurring with age, characterized by thinning of the periosteum, with gradual replacement of the steogenic layer by fibrous tissue, small amount of Haversian and Volkmann's canals, osteocyte lacunae voids and fine spongy bone trabeculae, allowing ample medullary space, usually occupied by fat cells and adipocytes. Morphologically, with respect to the quantification of the trabecular meshwork (Vv), we found statistically significant differences between Groups 1 and 3 and between Groups 2 and 3, with reduction of the trabecular meshwork of about 45% in the elderly over 65 years old ; there was no statistically significant difference between Groups 1 and 2. There was also no statistical difference between the Groups regarding Sv. Conclusion : the results of this experiment suggest that, in the elderly (over 65 years old), the osteogenic property of autologous bone graft decreases and the osteoconductive property is compromised.

RESUMO Objetivo: avaliar as características histológicas e morfométricas de biópsias ósseas da região anterior da crista ilíaca de pacientes de diferentes faixas etárias. Métodos: foram estudadas 30 amostras de osso da crista ilíaca, utilizando-se microscopia óptica de campo claro. As amostras foram divididas pela faixa etária dos doadores em três grupos: Grupo 1 (n = 10), indivíduos com idade entre 25 e 39 anos; Grupo 2 (n = 10), indivíduos com idade entre 40 e 64 anos; Grupo 3 (n = 10), indivíduos com idade igual ou superior a 65 anos. As amostras foram separadas aleatoriamente em dois conjuntos com 15 peças. No primeiro segmento do estudo (n = 15), foi avaliada histologicamente a propriedade osteogênica do enxerto, através da análise da reserva celular no periósteo, do número de osteócitos nas lacunas e da quantidade de canais de Havers e de Volkmann. No segundo segmento do estudo (n = 15), investigou-se morfologicamente a propriedade osteocondutora do enxerto, através da quantificação da rede trabecular (Vv) e da área trabecular (Sv). Resultados: histologicamente, observou-se que ocorre degeneração do tecido ósseo com a idade, caracterizada pelo adelgaçamento do periósteo, com substituição gradual da camada osteogênica por tecido fibroso, pequena quantidade de canais de Havers e de Volkmann, osteoplastos vazios e trabéculas finas de osso esponjoso, permitindo amplo espaço medular, em geral ocupado por células lipídicas e adipócitos. Morfologicamente, com relação à quantificação da rede trabecular (Vv), foi observada diferença estatisticamente significante entre os Grupos 1 e 3 e entre os Grupos 2 e 3, com redução da rede trabecular de cerca de 45% no idoso acima de 65 anos de idade; não foi observada diferença estatisticamente significante entre os Grupos 1 e 2. Não foi observada diferença estatística entre os grupos quanto à Sv. Conclusão: os achados do presente experimento sugerem que nos indivíduos idosos (acima de 65 anos de idade), a propriedade osteogênica do enxerto ósseo autólogo diminui e a propriedade osteocondutora está comprometida.

Treinamento em corrida de baixa intensidade: propriedades estruturais e mecânicas da epífise proximal do fêmur de ratas osteopênicas / Low-intensity running training: structural and mechanical properties of the proximal femoral epiphysis in osteopenic female rats / Entrenamiento en carrera de baja intensidade: propriedades estructurales y mecánicas de la epífisis proximal femoral de ratas osteopénicas

Este estudo investigou os efeitos do treinamento em corrida de baixa intensidade (TCBI) sobre propriedades estruturais e mecânicas da epífise proximal do fêmur de ratas osteopênicas. Ratas Wistar [idade = 20 semanas; massa corporal = 271,42 ± 17,6 g] foram submetidas à ovariectomia (OVX) ou laparotomia (SHAM) e alocadas em quatro grupos: corrida OVX (CO, n = 12), controle OVX (CONO, n = 12), corrida SHAM (CS, n = 12) e controle SHAM (CONS, n = 12). Quinze dias pós-cirurgia, os grupos CO e CS foram submetidos ao TCBI em esteira (16 m/min, 60 min/dia, cinco dias/semana) por 10 semanas. O TCBI não alterou os efeitos deletérios da osteopenia induzida por ovariectomia sobre a densidade mineral do fêmur, a quantidade de osso trabecular no trocanter e colo do fêmur, a tenacidade e a força máxima de fratura do colo do fêmur de ratas.

This study investigated the effects of low-intensity running training (LIRT) on the structural and mechanical properties of the proximal femoral epiphysis in osteopenic female rats. Female Wistar rats [age = 20 weeks, body mass = 271.42 ± 17.6 g] were subjected to ovariectomy (OVX) or laparotomy (SHAM) and divided into four groups: running OVX (RO, n = 12), control OVX (CO, n = 12), running SHAM (RS, n = 12) and control SHAM (CS, n = 12). Two weeks after surgery RO and RS groups were submitted to a progressive LITR on a treadmill (60 min / day, 5 days / week) for 10 weeks. The LIRT did not alter the deleterious effects induced by ovariectomy on the femoral bone mineral density, the quantity of trabecular bone in the femoral great trocanter and neck, and femoral neck tenacity and resistance to fracture in female rats.

Este estudio investigó los efectos del entrenamiento en carera de baja intensidad (ECBI) en las propiedades estructurales y mecánicas de la epífisis proximal femoral de ratas osteopénicas. Ratas Wistar con edad de 20 semanas (peso corporal: 271.42 ± 17,6 g) fueran sometidas a ooforectomía (OVX) o laparotomía (SHAM) y asignados en cuatro grupos: carera OVX (CO, n = 12), control OVX (CONO, n = 12), carera SHAM (CS, n = 12) y control SHAM (CONS, n = 12). Quince días después de la cirugía los grupos CO y CS fueran sometidos al ECBI (16 m/ min; 60 min/día, 5 dias/semana) durante 10 semanas. El ECBI no cambió los efectos deletéreos de la osteopenia inducida por ooforectomía sobre la densidad mineral del fémur, la cantidad de hueso trabecular en el trocánter y cuello del fémur, la tenacidad y la resistencia ósea a la fractura del cuello del fémur de ratas.

Effects of Running Speed and Duration on a Treadmill on Bone Properties in Ovariectomized Mice / The Japanese Journal of Rehabilitation Medicine

Effects of running speed and duration on a treadmill on bone properties were investigated in ovariectomized (OVX) mice. Sixty female ICR mice, twelve-weeks-old, were used in this study. They were divided into six groups of 10 mice each : either the SHAM, OVX, OVX+running groups (AS, AL, BS, BL), randomly. Running groups ran on the treadmill at 8 (A) or 16 (B) m/min, for 25 (S) or 50 (L) min, 5 days/week, for 10 weeks, respectively. After this, both femur and tibia bones were excised from the hind limb, and removed off surrounding tissues. Thereafter, bone mechanical strength (3 point bending test), dry bone weight and also ash content of the bones were determined. Bone mechanical strength and ash content of the femur and tibia in AL, BS, and BL mice were significantly higher than those in OVX mice. Running speed had effects on the bone mechanical strength and ash content of both bones significantly. Group BL showed the maximum values in bone properties among the running groups. This study suggested that a combination of running speed and duration could affect bone properties more significantly than the amount of exercise alone.

Effects of Electrical Stimulus on Bone Properties in Rats with Sciatic Denervation / The Japanese Journal of Rehabilitation Medicine

This study investigated the effects of electrical stimulus on bone properties in rats with sciatic denervation. Forty-eight Wistar rats aged 8 week-old were used and divided into 4 groups, randomly. One group was sham-operated (SHAM) as a control, and the sciatic nerves of the lateral hind limbs were cut in the remaining 3 groups (DN). Two groups of DN rats received electrical stimulus at both hind limbs to induce planter flexion for 15 min, 2 sets/day, 5 days/week, at 15 or 60 Hz. The rats in each group were sacrificed at 1, 2, 3 and 4 weeks after the operation. All tibias were measured by three-pointed bending test, and bone mechanical strength was calculated. Also, the dry bone weight and ash content of the bones were measured. A reduction of all bone properties in DN was shown from a week after operation onwards and that in DN+15 Hz from two weeks after operation onwards. Bone properties in DN+60 Hz were decreased in order of maximum load, ash content, mechanical strength, and dry bone weight from two weeks after operation onwards. These results suggest that electrical stimulus can delay the progression of bone atrophy, and that high frequency stimulation (60 Hz) is more effective than low frequency stimulation (15 Hz) in this regard.