title: Hypertrophy of ligamentum flavum in lumbar spine stenosis associated with the increased expression of connective tissue growth factor.
abstract: Hypertrophy of the ligamentum flavum (LF) contributes to lumbar spinal stenosis (LSS), and results mainly from fibrosis. Connective tissue growth factor (CTGF) is a profibrotic factor involved in the fibrotic process. This study aimed to evaluate CTGF expression in hypertrophied lumbar LF and the involvement of CTGF in LF hypertrophy. Ten patients with LSS were enrolled in this study. The control group included 10 patients with lumbar disc herniation. LF thickness was measured on the preoperative axial T1-weighted MRI. LF samples were collected during surgery. LF fibrosis was scored by Masson's trichrome staining. CTGF expression was determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. Correlation between LF thickness and CTGF expression was analyzed. Human LF cells were cultured and treated with recombinant human (rh) CTGF. Expression of types I and III collagen was determined by real-time PCR and ELISA. The thickness and fibrosis scores of LF in the LSS group were higher than that in the control group (all P < 0.001). CTGF was expressed in the extracellular matrix of all ligament samples, and was significantly higher in the LSS group than that in the control group (P < 0.001). The increase of CTGF expression was positive correlation with the LF thickness (r = 0.969, P = 0.000). rhCTGF treatment increased the mRNA expression and protein synthesis of types I and III collagen of the LF cells (all P < 0.001). Our results suggest that the increased expression of CTGF is associated with hypertrophy of the LF in patients with LSS.
authors.affiliation: Department of Orthopedic and Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China.
authors.forename: Zhao-Ming
authors.initials: ZM
authors.lastname: Zhong
authors.forename: Ding-Sheng
authors.initials: DS
authors.lastname: Zha
authors.forename: Wen-De
authors.initials: WD
authors.lastname: Xiao
authors.forename: Song-Hui
authors.initials: SH
authors.lastname: Wu
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fu-Qiang
authors.initials: FQ
authors.lastname: Liu
authors.forename: Jian-Ting
authors.initials: JT
authors.lastname: Chen
mesh_terms: D016022:Case-Control Studies; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000378:metabolism*; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000378:metabolism; D007405:Intervertebral Disc Displacement / Q000378:metabolism; D017843:Ligamentum Flavum / Q000378:metabolism* / Q000473:pathology; D008159:Lumbar Vertebrae / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013130:Spinal Stenosis / Q000378:metabolism* / Q000473:pathology
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D055513:Connective Tissue Growth Factor