EXPRESSION OF MMP-2 AND 4 IN SPINAL NODULAR DISCS AND THEIR CLINICAL RELATIONSHIP

Gang Gao¹, Feng Chang¹, Ting Zhang¹, Xinhu Huang¹, Chen Yu¹, Zhaolin Hu¹, Mingming Ji¹, Yufen Duan^{2, *}

¹Department of Spinal Minimally Invasive Surgery, Shanxi Provincial People's Hospital, No.29, Shuangta Si Street, Taiyuan City, 030012 - ²Endocrinology Department, Shanxi Coal Central Hospital, 101 Xuefu Street, Xiaodian District, Taiyuan City, 030006

Objective: To investigate the differences in the expression of matrix metalloproteinase-2 and -14 (MMP-2 and -14) in spinal tuberculosis intervertebral disc tissues, and their clinical relationship. 

Methods: 42 patients in our hospital with spinal tuberculosis were selected for inclusion in the study between January 2014 and January 2015, as well as 42 patients with fractures. The mRNA expression levels of MMP-2 and -14 in their tissues were measured using real-time fluorescence quantitative PCR, and the relationship between the mRNA expression levels of MMP-2 and -14, along with the clinicopathological characteristics of the patients with spinal tuberculosis, were analyzed. The correlation between the mRNA expression levels of MMP-2 and -14 in the spinal tuberculosis intervertebral disc tissues was further analyzed. According to the median of the relative expression of MMP-2 and -14 in the spinal combined intervertebral disc tissues, all the spinal tuberculosis intervertebral disc tissues were divided into a relatively-high expression group and the relatively-low expression group. The relationship between the mRNA expression levels of MMP-2 and -14 was analyzed, along with the prognosis of patients. 

Results: The mRNA expression levels of MMP-2 and -14 in the spinal tuberculosis intervertebral disc tissues were significantly higher than those in the normal intervertebral disc tissues (P<0.05). The expression level of MMP-2 mRNA was correlated with the age and smoking status of patients with spinal tuberculosis (P<0.05). The expression level of MMP-14 mRNA, meanwhile, was not associated with the age or smoking status of patients with spinal tuberculosis, nor was it associated with gender, work intensity, diseased intervertebral segments, or pain level (P>0.05). The median postoperative survival time of patients with a high expression of MMP-2 mRNA was significantly reduced, at 18.71 months, compared with 41.21 months for patients with a low expression of MMP-2 mRNA (P<0.05). The median survival time for patients with a high expression of MMP-14 mRNA was significantly lower, at 18.95 months, than the 42.00 months for patients with a low expression of MMP-2 mRNA (P<0.05). The expression level of MMP-2 can be utilized as an independent risk factor that affects the prognosis of patients with spinal tuberculosis. After Spearman's correlation analysis, the expressions of MMP-2 and -14, in the intervertebral disc tissues of patients with spinal tuberculosis, showed a significant positive correlation (r=0.439, P<0.01). 

Conclusion: The expressions of MMP-2 and -14 in patients with spinal tuberculosis are significantly increased, and the expressions of MMP-2 and -14 in the intervertebral disc tissues of patients with spinal tuberculosis are significantly positively correlated with each other. In addition, MMP-2 can independently indicate the prognosis of patients with spinal tuberculosis; measurement of its expression should play an important role in the treatment of patients with spinal tuberculosis.