Evaluation of Antioxidants in Bone Mineral Density of Iranian Osteoporotic Women

Abstract

Objective(s) Bone is a dynamic tissue that is continuously renewed throughout life by the process of bone remodeling. Antioxidant system might be involved in the pathogenesis of bone loss, so the aim of this study was to evaluate the total antioxidant capacity (TAC), vitamin C and vitamin E levels of plasma besides measuring enzymatic antioxidants, superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) enzymes activity in Iranian osteoporotic women comparing to the control group. Materials and Methods Bone mineral density (BMD) of the femoral neck and lumbar spine was measured by dual x-ray absorptiometry. The participants were divided into groups: a) total participants (-3.9 ≤ T–score ≤ 3.6) including 192 women, b) the control group (T-score ≥ -1) including 76 women, c) the total patients (T-score < -1) including 76 women. Then, plasma TAC, vitamin C levels, SOD and GR activities, erythrocyte CAT were measured using spectrophotometrical methods separately, and for vitamin E by HPLC analysis. Results Comparing the control group and osteoporotic women showed that: a) plasma levels for vitamin C and erythrocyte CAT were markedly lower in the patients than in the controls, but plasma activity of TAC, SOD and GR were significantly higher, respectively. b) the differences were higher between control and patients with severe disease (T-score <-1.7) comparing to patients in the group with milder disease (-1.7 ≤ T-score <-1). c) Femoral neck BMD adjusted with age and BMI showed a positive and significant correlation with plasma levels of vitamin C in all subjects, but this relation was reverse or negative for TAC, SOD and GR. Conclusion It seems that a physiologic increase in the amount of some antioxidants occurs in osteoporosis; even though this amount may not be sufficient for the human body requirements.