Metformin Does Not Protect Against Bone Loss or Mechanical Deficiencies in a Streptozotocin-Induced Mouse Model of Diabetes

<p dir="ltr">The prevalence of diabetes is increasing worldwide. A negative effect of poor diabetes management is increased fracture risk. Pre-clinical research has been conducted to reduce bone fracture risk by treating skeletal deficiencies in diabetic mice with repurposed osteoporosis medications. However, this approach may not be applicable to clinical practice since patients would likely first be treated to get diabetes under control. Metformin is a drug used to treat elevated glucose levels in patients with diabetes. In the current study, male C57BL/6J mice were randomly divided into four groups: control vehicle (CV), control Metformin (CM), diabetic vehicle (DV), and diabetic Metformin (DM) to determine Metformin’s effects on bone health in healthy and diseased mice. Mice were chemically induced with diabetes via streptozotocin (STZ) injections at 16 weeks of age and were treated with Metformin or vehicle for four weeks starting at 21 weeks of age. Bones were harvested and underwent microcomputed tomography scans to characterize trabecular and cortical bone architecture, then were mechanically tested to failure to determine bone mechanical properties. Metformin had a negative effect in healthy mice (CM group) with only four out of 15 reaching the end of the study. It also did not improve bone health in diabetic mice compared to vehicle-treated diabetic mice. Blood glucose was not significantly changed between the DV and DM groups nor relative to CV. Results suggest that a different model of diabetes such as a high fat diet and/or a longer treatment duration may be needed to further investigate the impacts of Metformin.</p>