Caloric restriction minimizes aging effects on the femoral medial condyle.

This study aimed to analyze the effects of caloric restriction on aged femoral articular cartilage of Wistar rats. Three groups of eight animals each were considered: young (YC) and old (OC) control groups fed with a normal diet and old caloric restriction group (OCR) composed of 18-month-old animals fed with a 31% less caloric diet from 6-months of age. Articular cartilage was studied through morphometry and immunohistochemistry. Body mass was 12% less in the OCR group than in the OC group. The articular cartilage from OC rats show thinner medial condyles, fewer chondrocytes, smaller chondrocytes nuclear volume and, in both condyles, a predominance of collagen type II and less collagen density compared to both YC and OCR groups (p < .001). In contrast, OCR articular cartilage show thicker medial condyles, larger chondrocytes nuclear volume and increased collagen density compared to OC group (p < 0.001). We concluded that caloric restriction minimizes the effects of aging on medial condyles of the femoral articular cartilage.

Effects of aerobic training, resistance training, or combined resistance-aerobic training on the left ventricular myocardium in a rat model.

This study follows the left ventricular (LV) hypertrophy in rats undergoing aerobic training alone (A), resistance training alone (R), or combined resistance and aerobic training (RA) (usually referred as concurrent training) program. A sedentary control group (C) was included. LV remodeling was evaluated using electron and light microscopy. The LV weight to body weight (LVW: BW) increased 11.4% in A group, 35% in the R group, and 18% in the RA group compared to the C group. The LV thickness increased 6% in the A group, 17% in the R group, and 10% in the RA group. The LV internal diameter increased 19% in the A group, 3% in the R group, and 8% in the RA group compared with the C group. The cross-sectional area of cardiomyocyte increased by 1% with the A group, 27% with R group, and 12% with RA training. The capillary density increased by 5.4% with A training, 11.0% with R training, and 7.7% with RA training compared with the C group. The volume fraction of interstitial collagen increased by 0.4% with training A, increased by 2.8% with R training, and 0.9% with RA training. In conclusion, except for the LV internal diameter, which increased more in the A group, the cardiac parameters increased more in the R group than in the other groups and in RA group than in A group. Collagen density increased from 5.4 ± 0.8% in the C group to 5.8 ± 0.6% in the A group (n. s.) (P > 0.05), to 8.2 ± 0.7% in the R group (P < 0.05), and to 6.3 ± 0.4% in the RA group (P < 0.05). These results demonstrate a significant increase for collagen content in the LV with R and RA exercise, but the increase was higher with R training alone than with RA training.

Histomorphometrical analysis on the effects of two therapeutic ultrasound intensities on fracture healing in aged rats / Estudo histomorfométrico comparativo dos efeitos de duas intensidades de ultrassom terapêuticos na consolidação de fratura da tíbia em ratos idosos

Introduction Experimental studies conducted in young animals show that therapeutic ultrasound (TUS) has been successfully used to shorten the healing time of bone fractures. However, they were not found in the literature, studies comparing the effect of different intensities of UST in aged animals. Objective To test the efficacy of intensity 1.0 W/cm2 and of 0.5 W/cm2 in the consolidation of experimental fracture of the tibia from aged Wistar rats. Materials and methods Three groups of 15 month old rats were submitted to a midshaft osteotomy of the tibia and then, the hind member was immobilized with a metal splint and plaster of Paris, wrapping the knee and ankle joint. One group (L), received ultrasound at 0.5 W/cm2; the other group (I), were exposed to ultrasound at 1.0 W/cm2. One control group (C), did not receive the ultrasound. Fifteen animals (five from each group) were euthanatized at the end of the first week and fifteen (five from each group) at the end of the third week. The progress of the fracture healing was performed for each group by morphometric analysis of histological sections of the fracture region. Results and conclusion The results showed that fractures treated with ultrasound at 1.0 W/cm2 healed significantly faster than did the fractures treated with ultrasound at 0.5 W/cm2 and the control. .

Introdução Trabalhos experimentais realizados em animais jovens mostram que o ultrassom terapêutico (UST) tem sido utilizado com sucesso para abreviar o tempo de consolidação de fraturas ósseas. Entretanto, não foram encontrados na literatura, trabalhos comparando o efeito de diferentes intensidades de UST em animais idosos. Objetivo Comparar a eficácia de duas intensidades de UST, de 0,5 W/cm2 e de 1,0 W/cm2 na consolidação de fratura experimental da tíbia de ratos Wistar idosos. Materiais e métodos Três grupos de ratos com 15 meses de idade foram submetidos a osteotomia da diáfise da tíbia e a seguir o membro inferior foi imobilizado com uma barra de metal, tornando imóveis as articulações do joelho e do tornozelo. Um grupo de animais (L) recebeu UST a 0,5 W/cm2; o outro grupo (I) foi submetido ao UST de 1,0 W/cm2. Um grupo controle (C) não recebeu aplicação de UST. Quinze animais (cinco por grupo) foram sacrificados após uma semana e outros quinze animais (cinco por grupo) após três semanas de imobilização. O progresso de consolidação da fratura foi obtido para cada grupo através de avaliação morfométrica de cortes histológicos da região da fratura. Resultados e conclusão Os resultados obtidos mostram que, em ratos idosos, as fraturas tratadas com UST de 1,0 W/cm2 consolidaram mais rapidamente que as tratadas com o UST de 0,5 W/cm2 e as do grupo C. .

Menopause, exercise, and knee. What happens?

OBJECTIVE: To check if ovariectomy produces alterations in the articular cartilage structure of the tibial proximal epiphysis and if aerobic physical exercise has any influence on these alterations. METHODS: Six-month-old female Wistar rats were distributed in three groups: Control group (CG), without ovariectomy and physical activity; Oophorectomy and sedentary group (OSG), with bilateral ovariectomy and without physical activity, and Oophorectomy and trained group (OTG), with bilateral ovariectomy and physical activity during 3 months. All rats were euthanised at 9 months of age. The results were obtained by using histological sections stained with Hematoxylin and Eosin, and Picrosirius stain. RESULTS: In relation to the thickness of the articular cartilage an increase was observed in the superficial layer in OSG in relation to OTG. The number of chondrocytes did not show any significant difference. The nuclear volume of chondrocytes in the superficial layer was higher in CG than in OSG . In the medium layer, the volume of chondrocytes was higher in CG than in OSG and the OTG. The same occurred when the values of the epiphysial cartilage was considered as a whole. For the collagen, the values of volume density of the collagen fibers were higher in the OSG and in the OTG than the CG. The same occurred with the OTG in relation to OSG. CONCLUSIONS: The depression of estrogen levels produced important changes in the tibial cartilage of Wistar rats mainly on the superficial layer and physical activity seemed to relieve these effects.

Estudo morfoquantitativo e imunohistoquímico da cartilagem articular do joelho de ratos Wistar submetidos à restrição calórica no envelhecimento / The morfoquantitative and imunohistochemistry study in the articular cartilage in the knee of Wistar rats submitted to caloric restriction in the aging

A doença degenerativa da cartilagem articular, ou osteoartrose, pode ser causada por diversos fatores, dentre eles o envelhecimento. Com o aumento da longevidade no Brasil, a prevalência da osteoartrose vai aumentar com o aumento progressivo da idade média da população nas próximas décadas. O estresse do dia a dia, com o avanço da vida moderna, são acompanhados pela má alimentação, sendo essa caracterizada por uma subnutrição ou até uma nutrição excessiva. Utilizando ratos Wistar, como modelo experimental, o objetivo deste trabalho é verificar se a alimentação com baixo nível calórico ameniza ou acelera as alterações na estrutura da cartilagem articular das epífises distal do fêmur e proximal da tíbia, causadas pelo envelhecimento. [...] Os animais do RC apresentaram na tíbia, manutenção da espessura, aumento do número de condrócitos bicondilar, manutenção do volume nuclear, aumento da densidade de colágeno, marcação menos heterogênea do colágeno tipo II no côndilo lateral, predominância desse tipo de fibras nas zonas média e profunda do côndilo lateral. No fêmur, os animais do RC mostraram aumento da espessura total pelo aumento da zona profunda no côndilo medial, aumento do número de condrócitos pelo aumento da zona profunda, sendo maior no côndilo medial, aumento do volume total dos núcleos dos condrócitos bicondilar, aumento da proporção volumétrica de fibras colágenas no côndilo medial, marcação heterogênea do colágeno tipo II e predomínio desse tipo de fibras nas três zonas da cartilagem. Dessa maneira, concluímos que os efeitos do envelhecimento e da restrição calórica são diferentes nas cartilagens articulares da tíbia e do fêmur. As alterações naturais do envelhecimento são amenizadas pela restrição calórica na cartilagem articular do fêmur, porém na cartilagem articular da tíbia, essas alterações são compatíveis com início de doença degnerativa sendo intensificadas pela restrição com sinias de avanço de osteoartrose

A degenerative disease of articular cartilage, or osteoarthritis, can be caused by several factors, including aging. With increased longevity in Brazil, the prevalence of osteoarthritis will increase with the progressive increase of the average age of the population in the coming decades. The stress of everyday life, with the advance of modern life, are accompanied by poor diet, this being characterized by malnutrition or even excessive nutrition. Using Wistar rats as experimental model, the aim of this work is to verify if feeding with low calorie softens or accelerates changes in the structure of articular cartilage of the epiphysis of the distal femur and proximal tibia, caused by aging. [...] The RC animals showed in the tibia, maintaining thickness, increasing the number of chondrocytes bicondylar, maintenance of nuclear volume, increased collagen density, less heterogeneous marking of type II collagen in the lateral condyle, the predominance of this type of fiber areas and average deep lateral condyle. In the femur, the animals RC showed increased of total thickness caused by increasing of the medial condyle deep zone, increasing the number of chondrocytes by increasing the deep zone, being greater in the medial condyle, increasing the total volume of the nuclei of chondrocytes bicondylar, increased volumetric proportion of collagen fibers in the medial condyle, heterogeneous marking of type II collagen and prevalence of this type of fiber in the three zones of cartilage. Thus, we conclude that the effects of aging and caloric restriction are different in the articular cartilage of the tibia and femur. The natural changes of aging are attenuated by caloric restriction in the articular cartilage of the femur, but in the articular cartilage of the tibia, these changes are consistent with early degenerative disease being intensified by restriction with signs of advanced osteoarthritis