High-frquency Loading with Rest Insertion Counterbalances High-fat-sucrose Diet Effects on Bone Properties

INTRODUCTION Changes in disease etiology in the past century highlight the need to examine environmental factors that influence the epidemic of chronic disease in modern society. For bone, fracture associated with osteoporosis can lead to severe morbidity or mortality and is increasing faster than demographic changes in the population. Bones meet competing demands both structurally and metabolically with an ability to adapt functionally to their environment. High-fat-sucrose (HFS) diets can adversely affect bone by limiting calcium availability and retention [1]. Conversely, applying mechanical stimuli, appropriate in magnitude, frequency, and rate can be osteogenic. As the response of bone to mechanical stimuli quickly saturates, the implementation of rest periods between loading cycles may circumvent the adaptive response saturation. The potential, counterbalancing effects of combining diet and rest-inserted high-frequency loading in a growing-bone model have yet to be examined. We hypothesized that mice exposed to a high-frequency, rest-inserted mechanical loading stimulus would accrue skeletal benefits, whereas the consumption of a HFS diet would adversely affect skeletal structural integrity. We anticipated that despite the osteogenic potential of loading stimuli, the calcium-limiting effects of a HFS diet would result in a net decrease in bone structural properties, when considered in combination.