Apoptosis and expression of apoptotic factors caspase-3, fas and p53 in lumbar ligamentum flavum / 中国组织工程研究

ABSTRACT

BACKGROUND: Lumbar spinal stenosis is one of the key causes of gait disorder and low back pain in the older adults. Hypertrophy of the ligamentum flavum is the main pathological mechanism leading to lumbar spinal stenosis. Although there are numerous imaging and pathological studies on the ligamentum flavum, little is reported on cell apoptosis. OBJECTIVE: To detect the apoptotic rate and the expression of caspase-3, fas and p53 in the hypertrophic ligamentum flavum, providing experimental evidence for understanding the mechanism underlying degeneration of the ligamentum flavum. METHODS: In experimental group, 50 hypertrophic ligamentum flavum specimens (L2-S1) confirmed by MRI and postoperative measurement were obtained from 50 patients with lumbar spinal stenosis who underwent posterior decompression surgery. There were 22 males and 28 females, aged from 32 to 74 years old, with an average of 54.46 years old. In control group, 30 non-hypertrophic ligamentum flavum specimens (L2-S1) confirmed by MRI and postoperative measurement were obtained from 30 patients with lumbar disc herniation undergoing surgery and lumbar burst fractures. There were 19 males and 11 females, aged 19-67 years, with an average of 47.27 years old. The apoptotic rate in the ligamentum flavum was detected by TUNEL staining, and the expression of caspase-3, fas and p53 was detected by SP immunohistochemistry. The study protocol was approved by the Ethics Committee of the Sixth Affiliated Hospital of Xinjiang Medical University, with approval No. LFYLLSJ2016007. RESULTS AND CONCLUSION: TUNEL results showed that the average apoptotic rate of the experimental group was (37.80±3.04)%, which was significantly higher than that of the control group [(13.18±1.34)%; t=41.83, P < 0.001]. The immunohistochemical staining of SP revealed that the positive expression percentages of caspase-3, fas and p53 in the ligamentum flavum were all 100% in the experimental group, while the positive percentages were 13.3%, 16.7%, and 10% in the control group, respectively. There was a significant difference between the two groups (P < 0.001). These findings indicate that cell apoptosis in the hypertrophic ligamentum flavum is increased and has a certain correlation with the up-regulation of caspase-3, fas and p53.