The Deleterious Effect of Bariatric Surgery on Cortical and Trabecular Bone Density in the Femurs of Non-obese, Type 2 Diabetic Goto-Kakizaki Rats

Background The effects of type 2 diabetes on bone mass and microstructure are not clear. The aim of this study was to evaluate bone microstructural properties and volumetric bone mineral density (vBMD) in type 2 diabetic Goto-Kakizaki non-obese rats after gastrojejunal bypass and their relationship with hormonal parameters. Methods We designed an experimental study in Goto-Kakizaki rats with and without gastrojejunal bypass, performing densitometric and microstructural studies of the distal femur using X-ray computed microtomography (micro-CT). Levels of insulin, glucagon, leptin, and glucagon-like peptide-1 (GLP-1) were also determined. Results We observed reduced cortical (1,488.92 ± 98.2 vs. 1,727.92 ± 133.45 mg/cm 3 , p = 0.028) and trabecular (180.8 ± 9 vs. 261.23 ± 45.54 mg/cm 3 , p = 0.036) vBMD in operated rats. Bone volume fraction (BV/TV) and trabecular connectivity were reduced in operated rats, while there was a reduction in cortical thickness and an increase in rod-like trabeculae at the expense of plate-like trabeculae. Leptin was reduced (1,042 ± 549 vs. 2,447 ± 1,035 pg/ml, p = 0.05) and GLP-1 increased (1.62 ± 0.32 vs. 0.96 ± 0.1 ng/ml, p = 0.008) but only leptin showed a significant association with vBMD Conclusions In type 2 diabetic Goto-Kakizaki rats, gastrojejunal bypass produces a reduction in cortical and trabecular bone mineral density and a deterioration in bone quality that could be explained, in part, by the reduction in leptin levels.