Expression of autophagy-related genes Beclin1 and LC3 in ossified tissues of posterior longitudinal ligament of cervical spine and correlation analysis with osteogenic factors

English Keywords:Posterior longitudinal ligament  Cervical spine  Autophagy  Osteogenic factor  Correlation

English Abstract:

  【Abstract】 Objectives: To investigate the expression levels of autophagy-related genes Beclin1 and LC3 in ossified tissues of posterior longitudinal ligament in cervical spine and their correlations with osteogenic factors. Methods: 18 posterior longitudinal ligament tissue specimens from cervical ossification of posterior longitudinal ligament(OPLL) patients underwent OPLL surgical removal from October 2020 to May 2021(OPLL group) and 15 tissue specimens of the posterior longitudinal ligament of the cervical spine that were not ossified(non-OPLL group) were collected. The morphological changes of posterior longitudinal ligament tissues were observed by hematoxylin-eosin(HE) staining; the deposition of calcium salts was observed by Von Kossa staining; The mRNA and protein expression levels of Beclin1, microtubule associated protein light chain 3(LC3), and the osteogenic factors runt-related transcription factor 2(RUNX2), bone morphogenetic protein-2(BMP2), and Osterix in the specimens of the two groups were determined with immunohistochemical staining and RT-qPCR respectively; Pearson correlation analysis was used to explore the relationship between Beclin1, LC3, RUNX2, BMP2, and Osterix. Results: Compared with the non-OPLL group, the cell morphology in the OPLL group was larger and irregular in shape, and the nuclei were more obvious; Von Kossa staining showed that there was no obvious calcium salt deposition in the non-OPLL group, whereas brownish-black calcium salts could be seen in the OPLL group, which were aggregated into flakes or clusters; The expression levels of Beclin1, LC3, RUNX2, BMP2 and Osterix proteins and mRNA in the OPLL group were higher than those in the non-OPLL group(P<0.05); Beclin1 mRNA expression level was significantly correlated with BMP2, RUNX2 and Osterix(P<0.05, r>0.5), while LC3 was not correlated with osteogenic factors. Conclusions: The autophagy-related genes Beclin1 and LC3 are significantly overexpressed in ossified tissues of posterior logitudinal ligament of cervical spine, and Beclin1 is closely related to posterior longitudinal ligament osteogenesis.