Although osteopenia has been associated with human diabetes mellitus, the pathogenesis of diabetic osteopenia is unclear. In the present study, we evaluated the effect of diabetes on histomorphometry, bone mineral density (BMD)-measured by dual-energy X-ray absorptiometry (DXA)-and biomarkers of bone metabolism in rats up to 120 days after the onset of experimental diabetes. Female Wistar rats with a regular estrous cycle were randomly divided into two groups: control rats (n = 15) and diabetic rats without insulin treatment (n = 25). Diabetes was induced by injection of alloxan and was confirmed by the determination of blood glucose concentration (>250 mg/dl). The results revealed an approximate threefold increase of femoral trabecular distance in diabetic rats compared to controls. Conversely, trabecular thickness and bone trabecular volume were reduced twofold and 77%, respectively. BMD in both the metadiaphyseal region and total area of the femur was found to be clearly reduced in diabetic animals, with no significant differences between the groups. Serum alkaline phosphatase (ALP) and tartarate-resistant acid phosphatase (TRAP) activities showed significant six- and twofold increases, respectively, in diabetic rats. There were significant decreases in serum calcium and albumin concentrations in diabetic rats, but no difference was observed in serum magnesium, phosphorus, or creatinine concentrations between the groups. Overall, our findings support the conclusion that the diabetic state is associated with alterations in bone turnover, resulting in the development of osteopenia, which is related to the time of evolution of the disorder.

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The relationship between lipid peroxidation, antioxidant defense and diabetic osteopenia remains unclear. This study evaluated the relationship among lipid peroxidation index, antioxidant defense parameters and bone metabolism in a premenopausal diabetic model using measures including thiobarbituric acidreactive substances concentration (TBARS) and reduced glutathione (GSH) content in brain homogenates, histomorphometric analysis, biomechanical testing and bone mineral density (BMD). Female Wistar rats with regular estrous cycle were divided into two groups: Group 1: control rats (n = 15) and Group 2: diabetic rats (n = 15). Diabetes was induced by alloxan and confirmed by glycemia ≥250 mg/dL. The lipid peroxidation index, measured by TBARS concentration, showed a significant increase (p<0.05) in diabetic animals in comparison to control animals. However, the antioxidant parameter measured by GSH content, was significantly lower (p<0.05) in diabetic animals. Histomorphometric analysis showed a significant increase (p<0.05) in femoral trabecular separation together with a significant decrease (p<0.05) in trabecular thickness, and reduced trabecular bone volume in diabetic rats. Moreover, biomechanical testing and BMD values were significantly lower (p<0.05) in the diabetic group. Thus, our results demonstrated that increased lipid peroxidation and altered antioxidant defense could be related to the development of oxidative stress and diabetic osteopenia in premenopausal rats.Uniterms: Oxidative stress. Lipid peroxidation. Diabetes mellitus. Diabetic osteopenia/experimental study.A relação entre peroxidação lipídica, defesa antioxidante e osteopenia diabética permanece obscura. Este estudo avaliou a associação entre índice de peroxidação lipídica, parâmetro de defesa antioxidante e metabolismo ósseo em um modelo diabético pré-menopausa através de medidas como a concentração de substâncias reativas ao ácido tiobarbitúrico (SRAT) e conteúdo de glutationa reduzida (GSH) no homogenato cerebral, análises histomorfométricas, teste biomecânico e densidade mineral óssea (DMO). Ratos Wistar fêmeas com ciclo estral regular foram distribuídos em dois grupos: Grupo 1 -ratas controle (n = 15) e Grupo 2 -ratas diabéticas (n = 15). O diabetes foi induzido pela aloxana e confirmado pela glicemia ≥250 mg/dL. O índice de peroxidação lipídica, medido pela concentração de SRAT, demonstrou um aumento significativo (p<0.05) nos animais diabéticos, em relação aos animais controle. Entretanto, o parâmetro de defesa antioxidante, mensurado pelo conteúdo de GSH, foi reduzido significativamente (p<0.05) nos animais diabéticos. As análises histomorfométricas mostraram um aumento significativo (p<0.05) da separação trabecular do fêmur, associado à diminuição significativa da espessura trabecular (p<0.05) e volume ósseo trabecular reduzido nas ratas diabéticas. Além disso, o teste biomecânico, V.M.G. Duarte, A. de S. Rodrigues, L.A. de Rezende, A.Ma. de O. Ramos, R.M. de Souza, F.P.F. Neto, A. da C. Medeiros 540 medido pela força máxima, e val...

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