The sex-specific effects of RAGE signaling and Type 2 Diabetes on mouse cortical bone mechanics, structure, and material properties

Individuals with type 2 diabetes (T2D) are prone to fracture at numerous skeletal sites despite presenting with a higher bone mineral density (BMD). The accumulation of Advanced Glycation End-products (AGEs) in the bone tissues of patients with T2D could be contributing to this paradox, of increased skeletal fragility with higher BMD. AGEs can impair bone cell homeostasis via the receptor for AGEs (RAGE). To investigate the effects of diabetes, AGE accumulation, and RAGE signaling on mouse cortical bone, we utilized male and female leptin receptor-deficient (db/db) mice from three age groups ranging from 3-14 months of age, which were crossed with animals carrying constitutively RAGE-deficient alleles (RAGE ^−/− ). The morphological, mechanical and material outcomes were measured using microCT, 3-pt bending, and an AGE assay. We observed significant impairments dependent on age and sex to the bone matrix and whole-bone mechanical behavior due to diabetes with some impairments alleviated with the ablation of RAGE. In older female diabetic mice, the removal of RAGE signaling prevented the deficits in bone mechanics, morphology and tissue mineral density (TMD). Male diabetic mice without RAGE signaling exhibited improved material properties. The study demonstrated that some bone impairments associated with T2D are prevented with RAGE ablation and may be partially reversible with the inhibition of RAGE signaling.