Evaluation of the association between biochemical and immunohistochemical score of caspase-9 and TNFα, and the grading of lumbar disc herniation.

ABSTRACT

OBJECTIVE: The aim of our study is to investigate the influence of caspase-9 and tumour necrosis factor alpha (TNFα) in the grade of lumbar disc herniation. We determined the strength of different predictors such as age, gender, disc grading, caspase-9 and TNFα. METHODS: We retrospectively reviewed 84 patients who had discectomies. Histological and biochemical evaluations of disc specimens were performed. All patients were scanned by the magnetic resonance imaging (MRI) scanner before the operation. Masson's trichrome stain, biochemical analysis and immunohistochemical staining were performed to measure the expression levels of caspase-9 and TNFα. The results were evaluated statistically. RESULTS: This study included 84 patients (mean age 41.59 ± 12.21 years; range 19-76) 60 men (age 40.47 ± 12.63 years) and 24 women (44.42 ± 10.81 years). No statistically significant age difference was found between the genders (p = 0.182). MRI scans showed 16 patients had protrusion, 44 had extrusion and 24 had sequestration of discs. There was a statistically significant negative correlation between the grading of lumbar disc herniations and age (p < 0.001, r = -0.509). Histological and biochemical analyses of disc materials were done. Inflammation, collagen fibre deterioration, apoptotic process, TNFα and caspase-9 were seen to increase with increasing disc grading (p < 0.01). CONCLUSIONS: Biochemical and immunohistochemical score of caspase-9 and TNFα indicate the grading of lumbar disc herniation. As the grading of disc herniation increases, inflammation of cells and collagen fibre disruption increase and accelerate the apoptotic process. Apoptosis in disc nucleus pulposus cells may reduce disc herniation.