Hyaluronan efect on bone healing in animal model of diabetes

Objective:Wound healing in diabetes is impaired due to a series of events that lead to a reduction of matrix production and therefore delayed bone formation. Hyaluronan is an important component of extracellular matrix and plays a key role in wound healing. Besides its important role in wound healing it also possesses other functions such as homeostasis and bone healing. The aim of this study was to evaluate the effects of 1% hyaluronan on bone calvaria defects in a type 1 diabetes model in rats. Material and methods:Type 1 diabetes was induced by streptozotocin injections(60mg/kg) in Wistar rats and diabetic state confirmed by glucose levels above 250mg/dl. Twenty animals were included in the study and two 6mm critical-size defects were created in the calvaria. Two treatments were tested: 1)1% hyaluronan gel and 2)saline. The animals were sacrificed at 4 and 8 weeks when biopsies were collected and processed for histological evaluation. Initial and final defect sizes were measured with an image analysis system and defect filling determined by difference between the former and the latter measurements. Non-parametric tests were applied for comparisons between times and treatments and Student t test applied to compare glucose levels and weight between diabetics and normal animals. A 5% significance level was established. Results:Diabetic animals had significant lower weight and higher glucose levels when compared to normal(p≤0.05) which reflects the diabetic state of those animals. Defect filling at 4 weeks was greater in normal animals(p≤0.05) in both treatment groups. At 8 weeks both animal groups showed similar bone filling(p>0.05) with both treatments. Healing of defects filled with hyaluronan did not differ from the ones filled with saline(p>0.05) showing no benefits of that treatment for the diabetic animals. Conclusion:Hyaluronan was not able to not improve bone healing in the diabetic animals. Supported by CNPq-Brazil.