Abstract
Lumber spinal stenosis occupies an important position as a significant factor that reduces activities of daily living in aging society. One of the main lesions is degenerative ligamenta flava where changes such as inflammation, ossification, angiogenesis, cartilaginous degeneration, and calcinosis may be occurred. This time, using degenerative ligamenta flava collected intraoperatively, we compared mRNA expression levels of various genes, cyclooxygenase-2 (COX2)/osteocalcin/endothelin-1/angiopoietin-1/bone morphogenetic protein-2 (BMP2)/interleukin-8 (IL-8), possibly associated with the above changes by dividing into 3 portions as follows: histologically almost normal (unaffected) portion; strongly affected paramedian (interlaminar) portion; and strongly affected portion proximal to bone attachments in the articular capsule. Histological examination was carried out with HE staining of 7 μm-frozen sections derived from ligamenta flava collected intraoperatively using cryostat. The mRNAs were extracted with microdissection of the portions after Cresyl Violet staining of the membrane frozen sections. The cDNA clones were replicated, and comparison of expression levels was performed using real-time PCR after reaction with primers for these genes. In the unaffected portion, expression levels of the genes were expected to be less, though, it was higher in IL-8 associated with angiogenesis compared to the other portions. Repair mechanism to micro lesions may lead to scarring and collagen fibers deposition even in the almost normal portion. Moreover, IL-8 expression was observed in the interlaminar and capsular portions, though, angiogenesis may have been more strongly induced in the former. Increased endothelin-1, involving mechanical stress, expression in the capsular portion was expected to actively cause changes, though, various genes associated with cartilage degeneration, ossification, or inflammation were accordingly expressed in the both interlaminar and capsular portions. In the degenerative ligamenta flava, not only endochondral ossification may occur in the bone attachments, but also thickening with bone formation in the portions without continuity with bones.
