Department of Spinal Surgery, First Affiliated Hospital of Xinjiang Medical University, Urumqi, China.
Neurochem Res. 2013 Sep;38(9):1914-20. doi: 10.1007/s11064-013-1097-x. Epub 2013 Jun 22.
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.
本研究旨在探讨端粒酶逆转录酶（TERT）在大鼠脊髓损伤后胶质瘢痕中的表达及其与胶质瘢痕形成的关系。将 120 只 Sprague-Dawley 大鼠随机分为三组：单纯脊髓损伤组（无 TERT 干扰）、TERT siRNA 组（TERT 干扰）和假手术组。采用改良 Allen 重物坠落法制作脊髓损伤模型。假手术组仅打开椎板暴露脊髓，不造成损伤。各组分别于脊髓损伤后 1、3、5、7、14、28、42、56 天麻醉处死 5 只大鼠。采用苏木精-伊红染色和免疫荧光检测观察胶质瘢痕形成情况，采用逆转录（RT）-PCR 和 Western blot 检测 TERT 和胶质纤维酸性蛋白（GFAP）的 mRNA 和蛋白表达。结果显示，TERT siRNA 组和单纯脊髓损伤组脊髓损伤区有神经胶质增生和胶质瘢痕形成，而假手术组未见明显变化。免疫荧光检测显示，单纯脊髓损伤组脊髓损伤后各时间点 GFAP 表达均显著高于 TERT siRNA 组（81%）和假手术组（2%）。相反，神经丝蛋白 200（NF-200）的表达逐渐减少，并在单纯脊髓损伤组稳定至 28 天。脊髓损伤后 56 天，脊髓胶质瘢痕和空洞内未见 NF-200 标记细胞。单纯脊髓损伤组各时间点 NF-200 表达均明显低于 TERT siRNA 组，而假手术组无变化。Western blot 显示，单纯脊髓损伤组 TERT 和 GFAP 蛋白表达呈动态变化，呈线性关系（r=0.765，P<0.01），而假手术组无明显线性关系（r=0.208，P=0.121）。RT-PCR 结果显示，单纯脊髓损伤组 TERT 和 GFAP mRNA 呈动态表达，呈线性关系（r=0.722，P<0.01），而假手术组无线性关系（r=0.206，P=0.180）。本研究结果表明，TERT 在脊髓胶质瘢痕中呈动态表达，与 GFAP 表达呈正相关，可能对促进胶质瘢痕形成起重要作用。
