兔退变腰椎间盘髓核细胞中衰老信号p16INK4a/pRb表达的体外研究

Objective To analysis the relationship between senescence signal p16INK4a/pRb and intervertebral disc degeneration, and to makesure the expression timeliness of the signal. Methods 16 adult rabbits, the L3/4 and L4/5 lumbar intervertebral discs of each rabbit were included in the experimental group, being operated to establish degenerative disc models;the L2/3 discs were included in the control group, without any treatment. Animals were then randomly divided into four model groups(2、4、8、12-weeks post surgery), each with four. Each group were taken tested by MRI and assessed at the corresponding time point. After that, the rabbits were killed respectively.Took the nucleus pulposus cells of each sample separately, cultured under the same environment, then the gene expression levels of MMP3, MMP13, p16INK4a, pRb in each sample were detected and analyzed by RT-PCR. Results 1. The MRI signals（T2WI）intensity in the nucleus pulposus of the experimental group significantly weakened with the extension of the time point，and the improved Thompson classification of MRI gradually biased seriously, the difference in each point of time was statistically significant(P<0.05)；2. In the experimental group， The mRNA expression of MMP3, MMP13, p16INK4a increased with the extension of the time point, while the mRNA expression of pRb gradually decreased. These changes were most obvious in the period of 4-8 weeks. The differences between experimental group and control group were statistically significant in the time of 4、8 and 12-weeks post surgery(P<0.01). Conclusions 1. The disc degeneration gradually became more serious with the extension of the time post surgery, and the trend was strongest in the period of 8-12 weeks post surgery. 2. As the disc degeneration became more serious, the expression of the senescence signal p16INK4a in the nucleus pulposus cells significantly increased, which had a negative correlation with the expression of pRb.