| It is well recognized that degeneration of the ligamentum flavum play a major role in the pathogenesis of neural canal stenosis. Degeneration of the ligamentum flavum would descent elasticity itself and the ligament arise wrinkle at spinal column extension, so neural canal capacity falls and nerve fiber is compressed, especially with disc herniation or joint proliferation. Numerous authors surmised that occurrence of degeneration of the ligamentum flavum related to age, or estrogen, or lesion through clinical observation. To confirm these views, we observed that change of age and level of estrogen and traction affect to histology and biomechanics of ligament through scanning electron microscope and transmission electron microscope and stretcher, et al. By the way, we discussed traction affect to chronic spinal cord lesion.1.The change of ligamentum flavum of rabbits with age related to degenerationObjective: To study the change of ligamentum flavum of rabbits with age related to degeneration.Methods: In the experiment, 24 Newzenland rabbits was used and divided into four group: 20days, 5mouths, 15mouths, 36mouths group(n=6). The rabbits were sacrificed with artery air-embolism. Immediately lumbar were removed and then ligament between L5-6 were resected. ①Optical microscope specimens were fixed in 10% formalin and reserved at room temperature. The specimens were embedded in paraffin, and subjected to Hematoxylin-Eosin and Weigert and CollagenⅡmRNA staining. ②Tissue for electron microscopy was fixed in 2.5% glutaraldehyde and reserved at 4℃in fridge. Ultra-thin sections were made for transmission electron microscope. ③After removing L4neural-ligamentum flavum-L5 neural complex, resected articular and interspinous and supraspinous ligaments carefully. Then we detected biomechanics items, area and thickness of ligament.Results: By H&E staining, 20 days group framework of the ligamentum flavum consisted of elastic fibres with interspersing a lot of thin collagenous matrix. And structure was loose, range was disheveled. Elastic fibres comprised a branching network of fibres. Many fibroblasts were seen. The ligament of 5 months group arrangement was more tighter and the fibres were more bigger. Major component was elastic fibres liked wave. Elastic fibres ran parallel with major axis of ligament interspersing collagenous matrix and comprised a branching network also. Fibroblast was little. Framework of 15 months group was same to 5 months group, but collagen fiber between elastic fibres was more. Ligament of 36 months group was characterized by rupture of elastic fibres. In the injured portion elastic fibres were lost or fragmented and the defect was filled with fibrous tissue. Elastic fibres were swollen and degenerated and the collagenous matrix was increased. The number of cell increased. Chondrocytes were seen. By Weigert staining, 20 days group framework of the ligamentum flavum consisted of black elastic fibres with interspersing a lot of thin red collagen fibres. Major component of 5 months group ligament was round black elastic fibres at cross section. Arrangement of ligament was more tighter and the fibres were more bigger. Little red collagen fibres were scattered around elastic fibres. Framework of 15 months group was same to 5 months group, but more flaky red collagen fiber between elastic fibres was scattered. Ligament of 36 months group was characterized by rupture of black and increasing red collagen fibres. It was not seen cells staining yellow in 5 and 15 months group ligamentum flavum, so expression of collagen Ⅱ mRNA was negative. The expression of 36 months group was positive faintly.Ultrastructural study revealed that fibres were arranged loosely, andbundles of elastic fibres which is composed of central amorphous elastin aggregates and peripheral elastin microfibrils about 10 nm in diameter were short and thin. A lot of collagen fibre bundles with periodic strip ran parallel each other among elastic fibres. Many fibroblasts were seen. Ligament o...
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