Correlation between the Expression of High Temperature Requirement Serine Protease A1 in Nucleus Pulposus Tissue and the Degree of Intervertebral Disc Degeneration.

Objective To investigate the correlation between the expression level of high temperature requirement serine protease A1 (HtrA1) in nucleus pulposus and the degree of intervertebral disc degeneration (Pfirrmann grade).Methods Thirty-six patients who underwent excision of nucleus pulposus were examined by magnetic resonance imaging (MRI) before operation,and the Pfirrmann grading of all patients was performed according to the sagittal T2 weighted MRI.The expression of HtrA1 in nucleus pulposus tissue was detected by reverse transcription polymerase chain reaction and Western blot.The correlation between the expression level of HtrA1 in nucleus pulposus tissue and Pfirrmann grade was analyzed.Results MRI in all 36 patients showed that there were 3 cases of Pfirrmann grade Ⅰ,10 cases of grade Ⅱ,11 cases of grade Ⅲ,7 cases of grade Ⅲ,and 5 cases of grade Ⅴ.The mRNA and protein expressions of HtrA1 in nucleus pulposus tissue increased with the increase of Pfirrmann grade.There were significant differences in the expression level of HtrA1 among different Pfirrmann grade groups (P<0.05) except for the difference between grade Ⅲ and Ⅴ (P>0.05).Spearman rank correlation analysis revealed that there was a rank correlation between expression level of HtrA1 and Pfirrmann grade (P<0.000 1).Conclusion The mRNA and protein expressions of HtrA1 in nucleus pulposus tissue increase with the increase of Pfirrmann grade,indicating HtrA1 is correlated with the degree of intervertebral disc degeneration.