Complex of growth differentiation factor-5 and fibrin gel for repair of lumbar disc injury in rabbits

Abstract

Objective To investigate the result of local injection of growth differentiation factor-5 (GDF-5) and fibrin gel for treatment of lumbar disc injury in rabbits.Methods Lumbar puncture with a 20-gauge needle was performed at L3/4,L4/5,and L5/6 discs of 40 New Zealand white rabbits.After needle puncture,L3/4 discs were injected with GDF-5 and fibrin gel (compound group) ; L4/5 discs fibrin gel (fibrin gel group) ; L5/6 discs nothing (blank control group).Two weeks later,intervertebral disc degeneration in each group was observed via radiography,MRI and nucleus proteoglycan content detection and histological examination.Results At postoperative 2-,4-,8-,and 12-weeks,X-ray films revealed a gradual decrease in disc height index (DHI) among the three groups,but the decreasing velocity was lower in compound group than in other two groups (P ＜ 0.05).On MRI,the signal of intervebral discs among the three groups diminished progressively with time,but a relatively lower decreasing was observed in compound group (P ＜ 0.05).At postoperative 4-week,proteoglycan content of the nucleus pulposus was (6.3-± 0.4) in compound group,higher than (5.9-0.4) in blank control group and (5.8-± 0.3)in fibrin gel group (P ＜0.05).At postoperative 2-week,histological evaluation showed (5.28 ±0.41)points in compound group,lower than (7.54 ± 0.53) points in blank control group and (7.21 ± 0.44)points in fibrin gel group (P ＜ 0.05).Conclusion Local injection of GDF-5 and fibrin gel facilitates the restoration of the injured discs and delays further disc degeneration. Key words: Lumbar vertebrae ; Intervertebral disk ; Growth differentiation factors ; Fibrin gel