Molecular Genetic Studies of Intraoperative Ligamentum Flavum Bioptates of Patients with Spinal Canal Stenosis

Abstract

Background. Ligamentum flavum is involved in the development of stenosis of the spinal canal and dural sac, but the mechanisms underlying degenerative-dystrophic changes have not yet been sufficiently studied. Aim. To study the expression of candidate genes potentially involved in connective tissue metabolism in intraoperative samples of Ligamentum flavum of patients with stenosis processes of spinal canal and duralsac on the lumbar spine.Materials and methods. During the surgical treatment, Ligamentum flavum biopsies were collected from 33 people with stenosis processes of spinal canal and dural sac on the lumbar spine (16 men, 17 women). RNA was isolated, then reverse transcription was performed. After that, real time PCR was performed (CFX96, Biorad) with the specific primers (RealTimePrimers.com).Results. The characteristics of the expression of candidate genes that are active in the Ligamentum flavum of the examined patient population are given: NAT1 and NAT2 acetyltransferase genes; genes that determine the intensity of local metabolism (Dio1, Dio2 and Dio3); estradiol receptor genes ESR1 and ESR2; genes encoding receptors for growth factors and parathyroid hormone. All Ligamentum flavum samples showed activity of the NAT, ESR 2, FGFR1, FGFR3, NA20, PTH1R, and PTH2R genes. In the vast majority of samples (93.9–97.0 %), the following genes were active: PDGFA, ESR1, CALCR, and PDGFB. In 21.2–39.4 % of samples, “silence” of the Dio1, Dio2, Dio3, NAT2 and GDF5 genes was detected, and only 39.4 % of samples revealed NAT1 transcripts. The highest heterogeneity of transcript content was observed for Dio1, NAT2, and Dio2. The most stable expression in Ligamentum flavum tissue and a narrow range of fluctuations were characterized by genes with a high level of activity AANAT, ESR2, NAA20 and genes with an average level of activity FGFR1, FGFR3, PTH1R and PTH2R.Conclusions. Ligamentum flavum is a promising little-studied substrate for molecular genetic research. The revealed features of gene expression provide new information about pathogenesis, and the new fundamental knowledge obtained can provide a basis for developing methods for preventing the development of epidural fibrosis.

Keywords

• stenosis of the spinal canal
• degenerative spine disorders
• ligamentum flavum
• gene expression
• real time pcr