This dissertation contains three sequential studies that investigate the influence of prediabetic or diabetic situations:​ (1) high fat-sucrose (HFS) diet-induced glucose intolerance, (2) moderate insulin-dependent diabetes, and (3) severe insulin-dependent diabetes, on the biomechanical, geometrical and histomorphometrical characteristics of immature rat femoral neck.

In the first study, Sprague-Dawley female rats were assigned randomly to a HFS diet group or a control-diet group for 10 wk. Cantilever-bending tests to failure were conducted, and geometrical and material properties were calculated from fracture-surface cross sections and were correlated with mechanical data. HFS diet produced maladaptive changes in the femoral neck structural and material properties in rapidly-growing animals.

In the second study, streptozotocin was used to induce diabetes. Rats were randomly divided into:​ control, moderate diabetic (MDM), and moderate diabetic with insulin (MDI) groups for 10 wk. Mechanical and geometrical measurements were the same as HFS study. Femoral necks in diabetic rats decreased the relative size of their cortical shell and increased their trabecular core. The load, energy, and normal stress at proportional limit, and total energy in diabetic femoral necks were significantly lower than control. Insulin treatment ameliorated diabetic osteopathy in the rat femoral neck.

In the third study, rats were randomly divided into:​ control (C), severe diabetic (SDM), and severe diabetic with insulin (SDI) groups for 10 wk. Mechanical and geometrical measurements were the same as previous studies, and histomorphometry on decalcified bone specimen were analyzed. Severe diabetes result in growth retardation. Compared to the control and SDI rats, SDM rats had significantly lower structural and material properties. After normalized by body mass, load and energy at proportional limit were still significantly lower in SDM rats than control or SDI rats. SDM rats showed significantly lower bone spicule/marrow space ratio and osteoclast number, and significantly greater porosity in the femoral neck cortex than control rats. When correlated to blood glucose level, bone material properties were most affected by diabetic severity, while bone geometrical and structural properties were less affected. The diabetic effect was most evident in load and energy at the proportional limit. Insulin treatment is essential in mitigating diabetic osteopathy.