Abstract:Objective To investigate the relationship between telomerase reverse transcriptase (TERT) gene expression and astrocyte activation.Methods Twenty neonatal 3-day-old male SD rats were used for culture of the astrocytes.The astrocytes were divided into Group A (activated,non-transfected astrocytes),Group B (activated,transfected astrocytes),Group C (unactivated astrocytes) and Group D (activated,empty plasmid transfected astrocytes) according to the random number table,with 5 rats per group.The cell proliferation rate in each group was detected by cell counting kit-8 (CCK-8) ;TERT expression by immunocytochemical method; expressions of TERT and glial fibrillary acidic protein (GFAP) genes by RT-PCR assay.Results Astrocytic proliferation ability in Group B lowered significantly as compared with that in Groups A,D and C (F =43.418,P < 0.01).Expressions of TERT and GFAP mRNAs in Groups A and D were significantly higher than those in Group B and C,and no significant difference was found between Groups A and D.Besides,there was a linear correlation between mRNAs expressions of both genes in Groups A and D (r =0.701,0.704,P < 0.01),while no significant linear correlation was observed in Groups B and C (r =0.260,P > 0.05).Expressions of TERT and GFAP proteins in Groups A and D were markedly higher than those in Groups B and C and no significant difference was found between Groups A and D.Conclusion TERT genes are involved in the activation of astrocytes and exert effect on promoting the activation of astrocytes.
[1]Lu P, Jones LL, Tuszynski MH. Axon regeneration through scars and into sites of chronic spinal cord injury. Exp Neurol, 2007, 203(1):8-21.
[2]Chen HX, Zheng XF, Sheng WB, et al. Transplantation of low-power laser-irradiated olfactory ensheathing cells to promote repair of spinal cord injury in rats. Neural Reqen Res, 2009, 4(3):171-177.
[3]Frisén J, Haegerstrand AH, Risling M, et al. Spinal axons in central nervous system scar tissue are closely related to laminin-immunoreactive astrocytes. Neuroscience, 1995, 65(1):293-304.
[4]Eddleston M, Mucke L. Molecular profile of reactive astrocytes-implications for their role in neurological disease. Neuroscience, 1993, 54 (1):15-36.
[6]Collins K, Mitchell JR. Telomerase in the human organism. Oncogene, 2002, 21(4):564-579.
[7]de Lange T. Shelterin: the protein complex that shapes and safeguards human telomeres. Genes Dev, 2005, 19(18):2100-2110.
[8]Blasco MA. Mice with bad ends: mouse models for the study of telomeres and telomerase in cancer and aging. EMBO J, 2005, 24(6):1095-1103.
[9]Meyerson M, Counter CM, Eaton EN, et al. hEST2, the putative human telomerase catalytic subunit gene, is up-regulated in tumor cells and during immortalization. Cell, 1997, 90(4):785-795.
[10]Collins K. Mammalian telomeres and telomerase. Curr Opin Cell Biol, 2000, 12(3):378-383.
[11]Choi J, Southworth LK, Sarin KY, et al. TERT promotes epithelial proliferation through transcriptional control of a Myc- and Wnt-related developmental program. PLoS Genet, 2008, 4(1):e10.
[12]Takano H, Murasawa S, Asahara T. Functional and gene expression analysis of hTERT overexpressed endothelial cells. Biologics, 2008, 2(3):547-554.
[13]Zhang RG, Zhao JJ, Yang LQ, et al. RNA interference-mediated hTERT inhibition enhances TRAIL-induced apoptosis in resistant hepatocellular carcinoma cells. Oncol Rep, 2010, 23(4):1013-1019.
[14]关于善待实验动物的指导性意见. 北京:中华人民共和国科学技术部. 2006:1-5.
[15]Araque A, Parpura V, Sanzgiri RP, et al. Tripartite synapses: glia,the unacknowledged partner. Trends Neurosci, 1999, 22(5):208-215.
[16]Yu AC, Lee YL, Eng LF. Inhibition of GFAP synthesis by ant-isense RNA in astrocytes. Neuroscience Res, 1991, 30(1):72-79.
[17]Fu W, Lee J, Guo Z, et al. Seizures and tissue injury induce telomerase in hippocampal microglial cells. Exp Neurol, 2002, 178(2):294-300.
[18]Liu J, Baykal A, Fung KM, et al. Human telomerase reverse transcriptase mRNA is highly expressed in normal breast tissues and down-regulated in ductal carcinoma in situ. Int J Oncol, 2004, 24(4):879-884.
[19]Hwang IK, Choi JH, Li H, et al. Changes in glial fibrillary acidic protein immunoreactivity in the dentate gyrus and hippocampus proper of adult and aged dogs. J Vet Med Sci, 2008, 70(9):965-969.
[20]Uchida K, Baba H, Maezawa Y, et al. Progressive changes in neurofilament proteins and growth-associated protein-43 immunoreactivities at the site of cervical spinal cord compression in spinal hyperostotic mice. Spine, 2002, 27(5):480-486.