老年大鼠T细胞凋亡相关基因表达模式的研究

Study on the expression pattern of T cells apoptosis-regulating genes in aged rats

目的 探讨老年大鼠 T细胞凋亡的基因表达模式。方法 本研究利用 TUNEL标记的流式细胞检测和荧光实时定量 RT- PCR技术 ,研究了老年大鼠和年轻大鼠 T淋巴细胞凋亡情况及抗凋亡和促凋亡基因 (Fas,Fas L ,bcl- 2 ,bax,TNFR1 ,TNFR2 )的表达差异 ,以及 Caspase8、Caspase3活性的变化。结果 与年轻大鼠相比 ,老年大鼠激活诱导的细胞凋亡百分率增高 ,有显著性差异 (P<0 .0 1 ) ;老年大鼠促凋亡的 Fas,Fas L,TNFR1基因表达上调 ,抗凋亡的 bcl- 2 ,TNFR2基因表达下调 ,与年轻大鼠相比均有显著性差异 (P<0 .0 5或 P<0 .0 1 )。此外 ,老年大鼠激活诱导的T淋巴细胞 Caspase8、3活性增高 ,与年轻大鼠相比有显著性差异 (P<0 .0 1 )。结论 激活诱导的 T细胞过度凋亡与衰老密切相关 ;促凋亡基因表达上调及抗凋亡基因表达下调及 Caspase8、3活性增高是老年大鼠 T细胞凋亡易感性增高重要分子机制。

Objectives To investigate the expression pattern of Apoptosis-regulting Genes of T lymphocyte in aged rats.Methods T lymphocyte apoptosis and the expression of genes promoting apoptosis (Fas/FasL, TNFR1 and Bax) and genes inhibiting apoptosis (Bcl2 and TNFR2) as well as the activity of caspase 3 and caspase 8 from young rats and old rats was studied using flow cytometry and real-time quantitative RT-PCR.Results Compared with the young rats,the aged rats exhibited enhanced activation-induced cell death in T lymphocyte. Meanwhile,the expression of apoptosis-promoting genes such as Fas FasL TNFR1 were higher in aged rats,but the expression of apoptosis-inhibiting genes such as Bcl-2 and TNFR2 were lower in aged rats. At the same time, we also observed the enhanced activity of Caspase8 and Caspase3 in aged rats. All the alternations stated above had statistical significance(P<0.05 or P<0.01).Conclusions The excessive apoptosis of activated T lymphocyte is closely related to aging. The upregulated expression of apoptosis-promoting genes and downregulaed expression of apoptosis-inhibiting genes,as well as the increased activity of Caspase8 and Caspase3 maybe the important mechanisms underlying the enhanced apoptosis susceptibility in aged rats.