Effects of zoledronic acid on bone structure and organization of nanocomposites in rats with obesity and limited mobility

Abstract Background: Some investigations show that obesity is associated with increase in bone mass due to excessive mechanical exertion. However, these data are contradictory as loss of mineral density of bone tissue and, respectively, the risk of fractures in this population group is higher. The aim of the research was to investigate impact of drug therapy with zoledronic acid on nanostructure of bones in rats with limited mobility and high-calorie diet. Methods: Rats (n = 56) were distributed into three groups: control (n = 18) – standard vivarium conditions, І experimental group (n = 18) – rats, which were on a high-calorie diet with limited mobility (HCD+LM), ІІ experimental group (n = 18) – HCD+LM+zoledronic acid. Zoledronic acid was injected at the dose 0.025 mg/kg intramuscularly every four weeks for six months. X-ray structure analysis, scanning electron microscopy and atomic absorption spectrometry were used for investigation of ultrastructure and quantitative assessment of mineral component loss in the femoral neck. Results: Obesity and limited mobility reduced the level of the mineral component in the femoral neck (−31.5%) compared with control. It is significant that zoledronic acid did not permit decrease in mineral component of the bone throughout the entire experiment compared with group I (+41.8%), and all parameters were higher than in control group (+15%). Conclusions: Obesity and limited mobility negatively affect mineral bone mass. Zoledronic acid induces increase in the mineral component as a result of remodeling inhibition under conditions of obesity and limited mobility modeling.