Nano-hydroxyapatite/collagen composites imitating cancellous bone for repair of massive bone defects in rabbits

Qingliu HU

ABSTRACT

BACKGROUND:

A nano-artificial bone imitating cancellous bone has been developed. It is necessary to perform a series of animal experiments regarding this artificial bone prior to clinical trials for providing technical information.

OBJECTIVE:

To evaluate the biodegradability, osteoconductivity, and osteoinductivity of nano-hydroxyapatite/collagen (nano-HA/CO) composites imitating cancellous bone.DESIGN, TIME AND

SETTING:

A randomized controlled animal experiment was performed at the Guangdong Medical Laboratory Animal Center between March and June 2007.MATERIALS The HA powder was synthesized by a co-precipitation reaction. The obtained HA powder was added into collagen solution at a certain ratio under vigorous stirring. The nano-HA/CO composites were frozen-dried to obtain nano-artificial bone. Fifteen New Zealand rabbits were randomly divided into 3 groups, with 5 rats per group blank control, coral-HA, and nano-HA/CO.

METHODS:

Following local anesthesia, 10 mm bone defect was made on the right ulnas in all rabbits. HA coral and Nano-HA/CO bone composites were inserted into the defects in the HA and nano-HA/CO groups, respectively. The blank control group received no any implantation. At 30 and 60 days following surgery, biocompatibility and osteoinductivity of cancellous bone resembling nano-HA/CO bone substitute were assessed by macroscopic examination, scanning electron microscopy, X-ray photography, and histological examination after implantation in vivo.MAIN OUTCOME

MEASURES:

Ultrastructure and degradation condition of nano-HA/CO bone substitute, postoperative wound healing, and osteo-regeneration in defect region.

RESULTS:

The nano-HA/CO bone composite possessed interconnected porosity and pore size resembling cancellous bone, which benefits in-growth of osteoblasts and blood vessels. At 30 days following surgery, the nano-HA/CO group exhibited that osteoblasts spread around, and ossification occurred in almost all newly formed bone area. At 60 days following surgery, the coral-HA group showed that only connective tissue regenerated without bone tissue regeneration and degradation of grafts.

CONCLUSION:

This nano-HA/CO bone composite shows great promise in repairing massive bone defect in stead of autograft.