Study On The Diversification Of Collagen Protein, Proteoglycan And Pathology In Lumbar Ligamentum Flavum

Objective:To study the relationship between the diversification of biochemical compositions in lumbar ligamentum flavum and the mechanism of central lumbar spinal stenosis;the thickness,collagen protein and proteoglycan of ligamentum flavum were measured and the pathological change were observed.Materials and Methods:Obtained from 18 patients with the central lumbar spinal stenosis by exairesis,35 ligamentum flavum specimens were used as experimental group,among of which 11,14,10 were L3/4,L4/5,L5/S1 respectively.At the same time,obtained from 13 patients with lumbar fracture,26 ligamentum flavum specimens from normal lumbar were used as control group,among of which 9,9,8 were L3/4, L4/5,L5/S1 respectively.The thickness of ligamentum flavum were measured by vernier caliper after operation,then stored in-80℃refrigerator.The collagen protein and proteoglycan of ligamentum flavum were determined by micro-hydroxyproline assay and sulfuric acid-carbazole.Microstructure were observed after HE and Masson staining on ligamentum flavum.Results:The result of thickness in lumbar ligamentum flavum experimental group L3/4 were(4.92±0.08)mm,L4/5 were (5.10±0.14)mm,L5/S1 were (4.25±0.27) mm,the control group L3/4 were (2.92+0.06)mm,L4/5 were (3.11+0.06)mm,L5/S1 were (2.40+0.12)mm,the thickness of ligamentum flavum in experimental group were higher than those in control group with a significant difference (P<0.05).The result of collagen protein in lumbar ligamentum flavum:experimental group L3/4 were (509.93±10.74)mg/g,L4/5 were (548.95±6.68)mg/g,L5/S1 were (481.02±20.15) mg/g;the control group L3/4 were (400.91+6.97)mg/g,L4/5 were (420.78+6.50)mg/g, L5/S1 were (382.76+6.23)mg/g, the collagen protein of ligamentum flavum in experimental group were higher than those in control group with a significant difference (P<0.05).The result of proteoglycan in lumbar ligamentum flavum: experimental group L3/4 were (74.29±2.28)mg/g,L4/5 were (103.08±4.14)mg/g, L5/S1 were (82.83±4.38)mg/g;the control group L3/4 were (27.60+1.06)mg/g, L4/5 were (30.88+1.15) mg/g, L5/S1 were (24.15+2.19)mg/g, the proteoglycan of ligamentum flavum in experimental group were higher than those in control group with a significant difference (P<0.05).Pathology showed that the elastic fibers of ligamentum flavum were disorganized and decreased in experimental group,while collagen fibers were proliferated and a small amount of cartilage were formed.The elastic fibers of ligamentum flavum were arranged regular and closely in control group,and a small amount of collagen fibers existed between elastic fibers.Conclusion:1.The thickness of ligamentum flavum in the central lumbar spinal stenosis were higher than the control group.Ligamentum flavum broken into the spinal canal,then the volume of spinal canal decreased and induced the low back pain.2.The content of collagen protein and proteoglycan in lumbar ligamentum flavum increased in the process of cataplasia,disordered the metabolism.The thickness of lumbar ligamentum flavum increased.3.Pathology showed that the elastic fibers of ligamentum flavum were disorganized, reduced and imbalanced in experimental group,and could increase the hypertrophy of ligamentum flavum.