Expression of bone morphogenetic protein-4 mRNA in the cervical posterior longitudinal ligament after decompression

Guodong CAI; Meng SI; Hui ZHANG; Junqin WANG

ABSTRACT

BACKGROUND:

It has been thought that posterior cervical decompression increases the risk of cervical instability and the stress on posterior longitudinal ligament may change growth factor expression in vivo. However, the association between BMP-4 expression and heterotopic bone formation has not been confirmed. Bone morphogenetic protein 4 (BMP-4) is one of factors that can lead to heterotopic bone formation alone.

OBJECTIVE:

To observe the effects of posterior cervical decompression on BMP-4 mRNA expression in the posterior longitudinal ligament.DESIGN, TIME AND

SETTING:

A randomized controlled animal experiment was performed in Taishan Medical College between January 2005 and December 2006.MATERIALS A total of 48 adult Sprague Dawley rats of either gender and of clean grade, weighing 270-350 g, were included in this study.

METHODS:

All rats were randomly and evenly divided into 3 groups experimental, sham-operated, and blank control. In the experimental group, C36 laminectomy for decompression was performed.In the sham-operated group only skin incision was made. Rats in the blank control group received no any treatment. Four rats were allocated for each time point (1, 2, 4, and 8 weeks post-surgery) for harvesting posterior longitudinal ligament.MAIN OUTCOME

MEASURES:

Detection of BMP-4 mRNA expression in the cervical posterior longitudinal ligament by semi-quantitative reverse transcription-polymerase chain reaction.

RESULTS:

In the experimental group, obvious BMP-4 mRNA expression was found at 1-8 weeks post-surgery. While no BMP-4 mRNA expression was found at all times in the sham-operated and blank control groups.

CONCLUSION:

Posterior cervical decompression can increase BMP-4 mRNA expression in the posterior longitudinal ligament.Endogenous BMP-4 may contribute to ligamentous ossification and development post-surgery.