The effect of insulin therapy on biomechanical deterioration of bone in streptozotocin (STZ)-induced type 1 diabetes mellitus in rats

Aims: To investigate the effect of insulin therapy on biomechanical properties of bone in streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM) in rats. Methods: A total of 28 male Wistar-Albino rats (12-week-old; 210-300 g) were divided into 4 groups (n = 7 for each) including control [C; no treatment], sham [Sh; distilled water i.p., for 8 weeks], diabetes [T1DM; 65 mg/kg of STZ, single i.p.] and diabetes + insulin treatment [T1DM + I; 65 mg/kg of STZ, single i.p. + insulin; 2-4 UI/day/rat, i.p., for 8 weeks] groups. Body weight, blood glucose levels (BGLs), bone mineral density (BMD) and geometric/mechanical properties of bone tissue were evaluated. Results: BGLs in diabetic rats were significantly increased compared to non-diabetic rats, while the body weights were decreased (p < 0.05). Femur length and cross-sectional area of femur were significantly decreased in both T1DM and T1DM + I groups (p < 0.05). The significant reduction obtained in BMD in T1DM rats compared with C and Sh (p < 0.05) groups was reversed by insulin treatment (p < 0.05). Displacement, absorbed energy, maximum load, ultimate stress and toughness were significantly decreased in T1DM and T1DM + I groups compared to C and Sh groups (p < 0.05). Conclusions: In conclusion, insulin treatment seems to be ineffective in restoration of biomechanical deterioration of bone specific to STZ-induced T1DM. (c) 2012 Elsevier Ireland Ltd. All rights reserved.