A comparative study on repairing bone defect with autograft and the composite of beta-tricalcium phosphate-hyaluronic acid-type Ⅰ collagen-bone marrow stromal cells

Ailin WEI; Xiaofeng YE; Shiling LIU; Hao PENG; Haiying TAO

ABSTRACT

BACKGROUND:

Compared with traditional autogenous bone graft, composite, as the carrier of seed cells, possesses advantages of fewer traumas and no limitation of donor site in repairing bone defect.

OBJECTIVE:

To observe the ability of the composite of β-tricalcium phosphate artificial bone-hyaluronic acid-type I collagen (β-TCP/HA/COL-I), as induced bone marrow stromal cell (MSC) carrier, to repair rabbit radial defect, and the feasibility with the composite as bone substitute material.

DESIGN:

A randomized and controlled trial.

SETTING:

Department of Orthopaedics, Renmin HospitaL, Wuhan University.MATERIALS; The study was conducted in the Department of Orthopaedics Renmin Hospital, Wuhan University between September 2003 and July 2004. Thirty-one New Zealand big white rabbits, aged 6 months, with body mass of 1.5 to 2.0 kg were enrolled in this study. The rabbits were randomized into control group (n =4) and experimental group (n =27).

METHODS:

①In vitro induction and culture of MSCs was performed on 31 white rabbits, and the alkaline phosphatase (ALP) positive ratio of induced MSCs was observed. The structure of β-TCP/HA/COL-I was observed under scanning electron microscope. ② A 2 cm radial defect was created through operation. Eight weeks later, composites of β-TCP/HA/COL-I/MSCs were implanted into one side of rabbits in the experimental group, and autogenous bone was implanted into the other side. Rabbits in the control group were untouched. ③All the animals in the experimental group were randomly sacrificed at postoperative 4,8 and 12 weeks, 6 rabbits at 4 and 8 weeks, 15 at 12 weeks; Animals in the control group were sacrificed at 12 weeks. Gross observation, X-ray photographing, haematoxylin-eosin (HE) dyeing, and assessment of inorganic ingredient were performed. Osteogenic area and biomechanical tests were performed at 12weeks. Repairing effects on bone defect in each group were compared.MAIN OUTCOME

MEASURES:

The ALP positive ratio of induced MSCs; The structure of composite ofβ-TCP/HA/COL-I;Gross observation; X-ray photographing; HE dyeing and assessment of inorganic ingredient; Osteogenic area and biomechanical tests.

RESULTS:

All the 31 rabbits entered the stage of result analysis. ① The ALP positive ratio of cells reached 75% after induction and culture. ② Scanning electron microscope observation showed that 3 kinds of materials with abundant cellular structure distributed evenly. ③ The osteogenic area at 12 weeks was (72.5±3.6)% and (76.7±6.2)% in the experimental group and autogenous group, respectively (P ＞ 0.05). ④The maximum bending moment was (521.0±61.1) and (554.3±53.3)N·mm in the experimental group and control group, respectively; The maximum displacement at point of application of force was (0.816±0.071)and (0.870±0.103)respectively, without significant difference (P ＞ 0.05). ⑤Inorganic ingredient in the composite was 75%, 57% and 42% at 4,8 and 12 weeks respectively, suggesting that the inorganic component in the material was gradually decomposed with the elongation of time. ⑥Results of gross observation,X-ray photographing, histopathological examination, biomechanical test showed that with the elongation of time, composite of β-TCP/HA/COL-I/MSCs could repair bone defect in the experimental group, while bone defect in the control group had not been repaired.CONCLUSTON Composite of β-TCP/HA/COL-I /MSCs possesses the same effect on repairing bone defect as autogenous bone, so it may be used as autogenous bone graft substitute.