Morphological, biomechanical and biochemical analysis of tendon of obese Zucker (fa/fa) rats / Analise morfologica, biomecanica e bioquimica de tendão de ratos Zucker (fa/fa) obesos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Obesity is considered a worldwide epidemic, one of the biggest public health problems in many parts of the planet, which grows in alarming rates. In Brazil, the decline in rates of malnutrition has been accompanied by rising rates of overweight and obesity, which can be defined as the accumulation of abnormal or excessive fat which presents a risk to health. Obesity significantly increases the risk of developing health problems as hypertension, stroke, respiratory problems, diabetes, cancer, cardiovascular diseases, skeletal muscle alteration and osteoarthritis. The tendons transmit the strength created in muscles to bones, allowing the joints movement. Tendons consist of cells (tenocyte and tenoblast) and an abundant extracellular matrix composed by collagen, proteoglycans and non-collagenous proteins. This study aimed to analyze the morphological, biochemical and biomechanical alterations of the deep digital flexor tendon in Zucker rats genetically obese (fa/fa) and of lean animals (Fa/_). Histological evaluation and immunohistochemical tests for collagen type III, showed no differences in tendons of both groups. Ultrastructural analysis, showed presence of lipid droplets on the bundles collagen. Only the obese animals showed disorganization in the distribution of fibrils. The diameter of collagen fibrils presented different distribution and mass-average diameter between the two groups, being bimodal in lean rats and unimodal in obese rats. With regard to mechanical parameters significant difference was observed, larger maximum displacement and strain in obese animals. The obese animals presented higher content of hydroxyproline while lean animals showed a larger amount of non-collagenous proteins and glycosaminoglycans. Due to the high overweight of the obese animals can be concluded that the obesity causes changes in the composition and organization of extracellular matrix of the tendon. These alterations may be related to organizational and structural changes of collagen bundles, influencing the mechanical properties of tendon and developments toward a pathological condition.

ASSUNTO(S)

biomecanica rats zucker morphology biomechanics morfologia ratos zucker tendons obesidade tendões obesity

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