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

The aim of this study was to evaluate the biomechanics and structural bone matrix in diabetic rats subjected to hyperbaric oxygen therapy (HBO).Twenty-four male rats were divided into the following groups: Control; Control + HBO; Diabetic, and Diabetic + HBO. Diabetes was induced with streptozotocin (STZ) in the diabetic Groups. After 30 days, HBO was performed every 48h in HBO groups and all animals were euthanized 60 days after diabetic induction. The femur was submitted to a biomechanical (maximum strength, energy-to-failure and stiffness) and Attenuated Total Reflectance Fourier 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)).In biomechanical analysis, diabetic animals showed lower values of maximum strength, energy and stiffness than non-diabetic animals. However, structural strength and stiffness were increased in groups with HBO compared with non-HBO. ATR-FTIR analysis showed decreased collagen maturity in the ratio of crosslink peaks in diabetic compared with the other groups. The bone from the diabetic groups showed decreased crystallinity compared with 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 compared with control and diabetic groups. Correlations between mechanical and ATR-FTIR analyses showed significant positive correlation between collagen maturity and stiffness.Diabetes decreased collagen maturation and the mineral deposition process, thus reducing biomechanical properties. Moreover, the study showed that HBO improved crosslink maturation and increased maximum strength and stiffness in the femur of T1DM animals

Energy of biomechanical analyses in different groups (*p<0.05).

<p>Energy of biomechanical analyses in different groups (*p<0.05).</p

Crystallinity index of ATR-FTIR analyses in different groups (*p<0.05).

<p>Crystallinity index of ATR-FTIR analyses in different groups (*p<0.05).</p

Amide I of ATR-FTIR analyses in different groups (*p<0.05).

<p>Amide I of ATR-FTIR analyses in different groups (*p<0.05).</p

Maximum strength of biomechanical analyses in different groups (*p<0.05).

<p>Maximum strength of biomechanical analyses in different groups (*p<0.05).</p

Matrix: Mineral ratio (Amide III+Collagen/Hydroxyapatite) of ATR-FTIR analyses in different groups (*p<0.05).

<p>Matrix: Mineral ratio (Amide III+Collagen/Hydroxyapatite) of ATR-FTIR analyses in different groups (*p<0.05).</p

Parameters analyzed by means of ATR-FTIR spectrums using the program OPUS 6.5.

<p>Amide I band (Collagen ratio between the mature pyridinoline crosslink peaks (PYR)– 1660 cm-1 and immature crosslinking dihydroxinorleucina (DHLNL) - 1690 cm-1); Crystallinity Index (The intensity ratio of peaks 551 and 597 cm-1 for 588 cm-1); Matrix-to-mineral ratio: Amide I + II/Hydroxyapatite (HA) (The ratio between integrated areas of amide I + II (1520–1720 cm-1) for HA (916–1180 cm-1)) and Amide III + Collagen/HA (The ratio between integrated areas of amide III (1210–1270 cm-1) with two collagen bands (1269–1296 cm-1 and 1180–1213 cm-1) for HA (916–1180 cm-1).</p

Stiffness of biomechanical analyses in different groups (*p<0.05).

<p>Stiffness of biomechanical analyses in different groups (*p<0.05).</p

Cortical segments of the femur obtained to perform analysis by the ATR-FTIR.

<p>Cortical segments of the femur obtained to perform analysis by the ATR-FTIR.</p