Effect of Nano-hydroxyapatite Concurrent with Bone Marrow Treatment on Experimental Bone Defect Healing in Rabbit: Radiological and Histopathological Evaluation

Nowadays, bone grafts are used in veterinary and human orthopedic to stimulate fracture healing, accelerate joint connection, and healing of bone defects. In this study, we carried out the radiological and histopathological evaluation of the effects of nano-hydroxyapatite concurrent with bone marrow treatment on rabbit fracture repair.

This experimental study was performed in the spring and summer of 2019 on 20 male New Zealand white rabbits (12-month-old, weight=2 kg). The samples were randomly divided into four groups, and bone segments were removed from the radius. In the first group (n=5) (control), the bone defect remained empty and no substance was injected. Meanwhile, the defects in the second, third, and fourth groups (sample size of five in each group) were filled with nano-hydroxyapatite, bone marrow, and combination of nano-hydroxyapatite and bone marrow. Radiographs of the radius in each rabbit were taken at 2nd, 4th, 6th, and 8th post-operative weeks, and bone biopsy was performed in the eighth week for histopathological assessment. In addition, the radiographs and samples were evaluated in terms of union, ossification activity, and re-forming.

In this study, there was a significant difference among the groups in the second, fourth, sixth, and eight weeks regarding radiographical assessments (P<0.05). However, the difference was more evident in the sixth week, when a significant difference was found between the nano-hydroxyapatite group and a combination of bone marrow and nano-hydroxyapatite group (P=0.02). In this regard, the latter had a better performance, compared to the former. In histopathological evaluation, the group of a combination of nano-hydroxyapatite and bone marrow showed higher ossification activities, compared to the control group.

According to the results of the study, the group of a combination of nano-hydroxyapatite and bone marrow had a better function in terms of bone healing, compared to the other two groups. Therefore, it is suggested that the method be applied to larger animal samples to confirm its clinical implications.