Expression and significance of Nebulin related anchoring protein(N-RAP) in the ossified posterior longitudinal ligament

English Keywords:Ossification of the posterior longitudinal ligament  Nebulin related anchoring protein  RT-PCR

English Abstract:

  【Abstract】 Objectives: To investigate the expression of Nebulin related anchoring protein(N-RAP) in the ossified posterior longitudinal ligament, and to explore its clinical significance. Methods: Ligament samples were harvested from the patients undergoing anterior cervical surgeries. 20 were from patients with OPLL and 10 from patients suffering from trauma were served as control group. All samples were fixed with formalin and embedded with paraffin. N-RAP polyclonal rabbit anti-human antibody, immunohistochemical SP method tablets and DAB color were used for immunohistochemical detection. Slices with satisfying staining were submitted for observation of cells expressing N-RAP(Brown-yellow staining). Samples from 5 ossified ligaments and 5 normal controls were submitted for RT-PCR. Samples were homogenizered on ice and total RNA was extracted. Real-time quantitative PCR was used to verify the mRNA expression of N-RAP in two groups. Results: 16 samples from ossified ligaments and 6 samples from normal controls got satisfying immunohistochemical staining. Immunohistochemistry showed that N-RAP expressed in cytoplasm in cellular components of ligament tissue. Cells expressing N-RAP were brown-yellow, while cells with no N-RAP were in blue. In ossified ligament from patients with OPLL, most cells were brown-yellow and a samll amount of blue cells without expressing N-RAP were observed. While in control samples, only blue cells with no N-RAP expression could be seen. Under real-time quantitative PCR detection，the average expression level of N-RAP was 14.29±4.70 in control groups, while 161.29±60.14 in ossified ligaments, which showed significant difference between two groups(P＜0.05). Conclusions: There is a higher expression of N-RAP in ligament tissue from patients with OPLL, which indicates that N-RAP may be involved in the onset or development of OPLL.