The study aims to determine the expression of telomerase reverse transcriptase (TERT) in the glial scar following spinal cord injury in the rat, and to explore its relationship with glial scar formation. A total of 120 Sprague–Dawley rats were randomly divided into three groups: SCI only group (without TERT interference), TERT siRNA group (with TERT interference), and sham group. The TERT siRNA and SCI only groups received spinal cord injury induced by the modified Allen’s weight drop method. In the sham group, the vertebral plate was opened to expose the spinal cord, but no injury was modeled. Five rats from each group were sacrificed under anesthesia at days 1, 3, 5, 7, 14, 28, 42, and 56 after spinal cord injury. Specimens were removed for observation of glial scar formation using hematoxylin-eosin staining and immunofluorescence detection. mRNA and protein expressions of TERT and glial fibrillary acidic protein (GFAP) were detected by reverse-transcription (RT)-PCR and western blotting, respectively. Hematoxylin-eosin staining showed evidence of gliosis and glial scarring in the spinal cord injury zone of the TERT siRNA and SCI only groups, but not in the sham group. Immunofluorescence detection showed a significant increase in GFAP expression at all time points after spinal cord injury in the SCI only group (81 %) compared with the TERT siRNA group (67 %) and sham group (2 %). In contrast, the expression of neurofilament protein 200 (NF-200) was gradually reduced and remained at a stable level until 28 days in the SCI only group. There were no NF-200-labeled cells in the spinal cord glial scar and cavity at day 56 after spinal cord injury. NF-200 expression at each time point was significantly lower in the SCI only group than the TERT siRNA group, while there was no change in the sham group. Western blotting showed that TERT and GFAP protein expressions changed dynamically and showed a linear relationship in the SCI only group (r = 0.765, P < 0.01), while there was no obvious linear relationship in the sham group (r = 0.208, P = 0.121). RT-PCR results showed a dynamic expression of TERT and GFAP mRNA in the SCI only group, exhibiting a linear relationship (r = 0.722, P < 0.01), while there was no linear relationship in the sham group (r = 0.206, P = 0.180). Our data indicate that TERT has a dynamic expression in the spinal cord glial scar, which positively correlates to GFAP expression, and may be important for promoting glial scar formation.

Abstract. The pathogenesis of lumbar disc degeneration is extremely complex, and the expression and role of telomerase in degenerative lumbar disc tissues remains unclear. The aim of the present study was to detect telomerase expression in nucleus pulposus tissues of degenerative lumbar discs and to explore the correlation between telomerase expression and other factors typical of disc degeneration. A total of 8 patients with degenerative nucleus pulposus were included as the experimental group and compared with 8 control patients without evident lumbar disc degeneration. The expression of telomerase in nucleus pulposus tissues was detected by immunohistochemical staining. ELISA was performed to determine the differential expression of telomerase, type II collagen and chondroitin sulfate between the two groups. In addition, a correlation analysis was performed to form associations between these factors. Finally, 5 cases in the experimental group and 5 in the control group were involved in the analysis. Immunohistochemistry results showed that telomerase expression in the experimental group was significantly lower compared to the control group and the percentage in the unit field of view showed significant differences between the two groups (P<0.05). Similarly, the ELISA test results showed lower expression levels of telomerase, type II collagen and chondroitin sulfate in the experimental group when compared with the control group (P<0.05). The correlation analysis revealed that telomerase was positively correlated with type II collagen and chondroitin sulfate (correlation coefficients, 0.673 and 0.528, respectively; P<0.01). In conclusion, telomerase is involved in the degeneration process of nucleus pulposus tissue in lumbar discs and has a positive correlation with other factors typically associated with degeneration.