Comprehensive Histochemical Evaluation of Age-Related Intervertebral Disc Degeneration

Objective: The intervertebral disc (IVD) is a fibrocartilaginous structure that plays a critical role in transmitting spinal loads and maintaining mobility. Age-related
degeneration of the IVD leads to the disruption of structural integrity, reduction in mechanical function, and the development of clinical symptoms such as back
and neck pain. During the degenerative process, matrix composition, cellular organization, and mechanical resilience are significantly affected. The aim of this study
was to investigate the histological and histochemical changes occurring in IVDs across different age groups using various staining techniques and to evaluate their
relationship with the degeneration process.
Materials and Methods: This study included 30 patients aged between 40 and 70 years who underwent surgical procedures for disc herniation during which IVD
specimens were obtained. Patients were divided into four age groups: Age40s (40–49 years, n=9), Age50s (50–59 years, n=7), Age60s (60–69 years, n=8), and Age70s
(70–79 years, n=6). Surgical specimens were fixed in 10% formalin, processed routinely, and embedded in paraffin. Sections of 5 μm in thickness were cut from
the paraffin blocks and stained with hematoxylin and eosin, toluidine blue, Masson’s trichrome, Congo red, and the Armed Forces Institute of Pathology method.
Histological changes were examined under a light microscope and semi-quantitatively scored.
Results: With advancing age, IVD tissues exhibited a marked decrease in proteoglycan content, an increase in collagen fiber density, accumulation of lipofuscin
granules, and the presence of amyloid deposits. In the older age groups, the matrix was observed to become denser and more fibrotic, and to show disruption of the
lamellar organization.
Conclusion: Histochemical staining techniques are effective in the detailed identification of cellular and extracellular matrix changes occurring during IVD aging
and degeneration. These methods contribute to the characterization of age-related structural alterations and provide valuable information for comparative
histopathological assessments of the degenerative process.