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It is generally agreed that combined deficiency of selenium and vitamin E leads to several abnormalities including Kashin-Beck disease which is an endemic and chronic degenerative osteoarthrosis. The abnormalities can be reversed by the administration of various forms of selenium and vitamin E. The present study was designed to investigate the effects of dietary selenium and vitamin E on bone tissue and on the biomechanical properties of bone. Young rabbits of both sexes were fed with either a selenium- and vitamin E-adequate diet (control group), or a selenium- and vitamin E-deficient diet or a selenium-excess diet. The selenium-deficient diet resulted in a significant decrease in plasma selenium level and the selenium-excess diet resulted in a significant increase in the plasma selenium level with respect to the corresponding control values (p < 0.05). The diets did not affect the blood cell counts considerably but erythrocyte glutathione peroxidase activity increased (decreased) relatively when the plasma selenium level increased (decreased) (p < 0.05). The light microscopic investigations of the bone tissues of the two experimental groups indicate that the findings of the present work are compatible with osteomalacia. The biomechanical properties of the bones from the three groups were determined experimentally with bending tests. Both the Se- and vitamin E-deficient diet and the Se-excess diet decreased the biomechanical strength of the bones significantly while the bones belonging to the control group always had the largest modulus of elasticity (p < 0.05).

Thirty-six female Sprague-Dawley rats were divided into two groups: oophrectomised (oestrogen deficient) rats and sham operated (oestrogen maintained) rats. Rats were sacrificed at six, ten, and 14 weeks. The rats were randomly chosen to have biomechanical evaluation on one side and histological evaluation on the other. Biomechanical testing was performed on an Instron machine to measure peak load. Histological sections were evaluated for cell proliferation, collagen-fibre organisation, fibroblast density, angiogenesis, inflammatory cells, chondroid and osseous metaplasia. Compared with the sham operated group, the oophrectomised group showed a lesser average maximum stress (42.9 N/m 2 versus 33.7 N/m 2 ) at six weeks, which was significant (p<.05). Succeeding weeks showed no significant biomechanical differences between the two groups. The sham operated group showed greater inflammatory response, which was statistically significant (p< 0.05), and also revealed greater cell proliferation and density. The results of this study revealed that endogenous oestrogen may improve healing of the Achilles tendon in rats.