Activity of Parathyroid Hormone Receptor Genes in Ligamentum Flavum Biopsies of Patients with Spinal Canal and Dural Sac Stenosis at the Lumbar Level

Parathyroid hormone receptors PTH1R and PTH2R are poorly studied in the pathology of the vertebral column and may be involved in both ectopic ossification of the vertebral ligaments and fibrous growth of the extracellular matrix, as well as in other unknown processes occurring in the pathological focus.

Aim. To study the expression of genes encoding parathyroid hormone receptors in intraoperative Ligamentum flavum samples of patients with stenosis of the spinal canal and the lumbar dural sac of the spine and to assess the correlation with the expression of other genes active in connective tissue in conditions of developing pathology.

Materials and methods. Studies of the Ligamentum flavum were performed in 33 patients (17 women, 16 men) with stenotic processes of the spinal canal and dural sac of the lumbar spine. RNA was isolated from the biopsies using Qiagen reagents (Germany). Then reverse transcription was performed. cDNA was used for setting up a polymerase chain reaction (Promega Reagents, USA) using a CFX96 thermal cycler (Biorad, USA) with specially selected specific primers.

Results. The expression of genes encoding parathyroid hormone receptors PTH1R and PTH2R was detected and evaluated for the first time in intraoperative Ligamentum flavum samples of patients with spinal canal and dural sac stenosis, and their relationship with the activity of genes encoding estradiol receptors (ESR1 and ESR2) and FGFR3 was revealed. For the first time, common features of PTH1R and PTH2R gene expression, as well as their differences, were revealed. It is proved that the intensity of expression of parathyroid hormone receptors in intraoperative Ligamentum flavum biopsies does not depend on age, gender, or the presence of bone and cartilage nodes according to MRI results. The interdependence of differential changes in the expression of genes of the receptor apparatus involved in the metabolism of Ligamentum flavum tissues was  revealed.

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