Gene expression of COX-2,IL-15, IL-8, TNF-alfa, IL-1 beta, IL-6, IL-1 alfa i̇n pati̇ents wi̇th and wi̇thout li̇gamentum flavum hypertrophy

Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in elderly. Ligamentum flavum (LF) hypertrophy plays a critical role in the pathogenesis of LSCS. Inflammatory agents induce the LF hypertrophy and increased scar tissue formation. This project aims to investigate the expression of genes (COX-2, IL-15, IL-8, TNF-alfa, IL-1 beta, IL-6, IL-1 alfa) that are responsible for the inflammatory process in hypertrophied LF tissue histopathologically and to compare with the normal LF tissue population. In our study, 25 samples of hypertrophied LF tissue were obtained from the patients with the diagnosis of LSCS while 25 samples were obtained from the patients who underwent surgery for lumbar disc herniation forming control group. Some of these samples were investigated for histological study. They were stained with Masson trichrome for analysis and grading of fibrosis. Furthermore, the rest of the LF samples in the LSCS and control groups were investigated for the expression of inflammatory cytokine genes (COX-2, IL-15, IL-8, TNF- alpha, IL-1beta, IL-6, IL-1 alpha gene) by RNA isolation. Following the qualitative and quantitative analysis of isolated RNA molecules, cDNA synthesis were carried out. COX-2, IL-15, IL-8, TNF-alpha, IL-1beta, IL-6, IL-1 alpha and housekeeping gene alpha aktin were analyzed for the expression levels by semiquantitative RT-PCR method. Cytokines were found both in LSCS and control groups. Any statistically significant difference was not found between LSCS and control groups in terms of COX-2, IL-15, IL- 8, TNF-alpha, IL-6 and IL-1 alpha. However, low levels of IL-1 beta was found in LSCS group. The effects of inflammatory cytokines in the pathogenesis of ligamentum flavum hypertrophy should be clarified.