Influence of hyperbaric oxygen on biomechanics and structural bone matrix in type 1 diabetes mellitus rats

BackgroundThe aim of this study was to evaluate the biomechanics and structural bone matrix in dia betic rats subjected to hyperbaric oxygen therapy (HBO).MethodsTwenty-four male rats were divided into the following groups: Control; Control + HBO; Dia betic, and Diabetic + HBO. Diabetes was induced with streptozotocin (STZ) in the diabeticGroups. After 30 days, HBO was performed every 48h in HBO groups and all animals wereeuthanized 60 days after diabetic induction. The femur was submitted to a biomechanical(maximum strength, energy-to-failure and stiffness) and Attenuated Total Reflectance Fou rier transform infrared (ATR-FTIR) analyses (crosslink ratio, crystallinity index, matrix-to mineral ratio: Amide I + II/Hydroxyapatite (M:MI) and Amide III + Collagen/HA (M:MIII)).ResultsIn biomechanical analysis, diabetic animals showed lower values of maximum strength,energy and stiffness than non-diabetic animals. However, structural strength and stiffnesswere increased in groups with HBO compared with non-HBO. ATR-FTIR analysis showeddecreased collagen maturity in the ratio of crosslink peaks in diabetic compared with theother groups. The bone from the diabetic groups showed decreased crystallinity comparedwith non-diabetic groups. M:MI showed no statistical difference between groups. However,M:MIII showed an increased matrix mineral ratio in diabetic+HBO and control+HBO com pared with control and diabetic groups. Correlations between mechanical and ATR-FTIR analyses showed significant positive correlation between collagen maturity and stiffness.Conclusions Diabetes decreased collagen maturation and the mineral deposition process, thus reducing biomechanical properties. Moreover, the study showed that HBO improved crosslink matu ration and increased maximum strength and stiffness in the femur of T1DM animals.