Degeneration of the lumbar spine and its relation to the expression of collagen and elastin in facet joint capsules and ligament flavum

OBJECTIVE: The aim of the study was to assess the relationship between the expression of elastin, collagen type I, II,III and the degeneration of the facet joint capsule and the ligamentum flavum. METHODS: 10 patients (4 male, 6 female) (mean age 61 ± 14,9) undergoing surgery for degenerative lumbar spine syndrome and 5 cadavers (3 male, 2 female) (age of death 87 ± 8,6 years) were included in this study. One set of tissue samples was taken from each patient in the patient group intraoperatively and two sets of samples were taken from each cadaver in the cadaver group posthumosly from the ligamentum flavum (medial and lateral) and from the facet joint capsules (superior and inferior articular process) at the L4/5 segment.Western blot analysis was performed for collagen types I, II, III and for elastin. Disc degeneration was scored according to the Pfirmann Classification, facet joint arthrosis was scored according to the Fujiwara Classification and their relationship with protein expression was investigated. RESULTS: There was a strong expression of Collagen type I in the patient group (PG) compared to the body donor group (BDG) in the facet joint capsule (FJC) and in the lateral samples of the ligamentum flavum. Samples of the FJC showed lower expression of elastin in the PG compared with the BDG, but without statistical significance. An increased expression of collagen type I compared to elastin in the PG could be shown. In contrast, elastin predominated in the samples of the BDG group compared to collagen type I (collagen type I/ elastin PG: PAsup 2,78; PAinf 2,61; LFmed 2,23; 225 LFlat 1,83; BDG: PAsup 0,15; PAinf 0,2; LFmed 0,2; LFlat 0,27). Rank correlation coefficient according to Spearman showed low to moderate correlations for collagen type I, III and elastin for the degree of disc degeneration according to Pfirrmann and the degree of facet joint osteoarthritis according to Fujiwara, all of them without statistical significance. CONCLUSION: This study has shown us that in the context of degenerative changes of the lumbar spine, there is an increased expression of collagen type I and a dominance over elastin. LEVEL OF EVIDENCE: Level III, Diagnostic Study