MTH2和MTH3蛋白在快速老化模型鼠SAMP8胸腺中增龄性表达的比较研究

Change of MTH2 and MTH3 Expression with Aging in Thymus of Senescence-accelerated Mouse P8

目的检测抗核酸氧化酶蛋白MTH2和MTH3在快速老化小鼠SAMP8胸腺中的表达,探讨其与SAMP8增龄性变化的相关性。方法选用1、4、8、12月龄的SAMP8小鼠及同龄的抗快速老化小鼠R1(SAMR1)作为实验对象。采用免疫印迹法检测胸腺中MTH2和MTH3蛋白的表达。结果免疫印迹结果显示,在SAM鼠胸腺中MTH3蛋白的表达量均显著高于MTH2。定量结果显示,1、4、8、12月龄的SAMP8胸腺中MTH3表达的灰度值(grey level)分别为0.546、0.322、0.207、0.164,显著低于同龄SAMR1(P<0.05),而MTH2在SAMP8和SAMR1胸腺中的表达却没有显著性差异(P>0.05)。与同组1月龄小鼠相比,MTH3在4、8、12月龄的SAMP8鼠胸腺中的表达量分别下降41%、62%、70%;在SAMR1鼠中分别下降19%、43%、67%,差异有统计学意义(P<0.05)。而MTH2在SAMP8和SAMR1胸腺中的表达也存在相同的增龄性下降的变化趋势(P<0.05)。结论MTH2和MTH3蛋白在SAMP8和SAMR1小鼠胸腺中的表达量均呈增龄性下降,提示MTH2和MTH3蛋白表达量的减少在SAM鼠胸腺的衰老过程中具有重要意义,其中MTH3蛋白表达量的减少可能与SAMP8小鼠胸腺的快速衰老密切相关。

Objective To detect the expression of anti - nucleic acid oxidase MTH2 and MTH3 in the thymus of senescence - accel- erated mouse P8 （ SAMP8）. Methods We randomly selected SAMP8 and its control strain SAMR1 aged 1 - , 4 - , 8 - and 12 - month and performed western blot analysis to observe the expression of MTH2 and MTH3 in thymuses of the two groups of mice. Results The results of Western blot showed that the expression of MTH3 in thymuses of SAM mice were significantly higher than MTH2. Meanwhile, the quantitative results showed that the grey values of MTH3 expression were 0. 546, 0. 322, 0. 207 and 0. 164 in thymuses of 1 - 12 months -old SAMP8 mice, and significantly lower than those in the age -matched SAMR1 mice （P 〈 0.05）. However, there wasn＇t significant difference in the expression of MTH2 in thymuses between SAMP8 and SAMR1 groups （ P 〉 0.05 ）. Compared with 1 month - old mice in the same group, the expression of MTH3 in thymuses of 4 - 12 months - old SAMP8 had dropped by 41% , 62% and 70% respectively. The same pattern was also observed in SAMR1 mice, and the descendent value were 19% , 43% and 67% （P 〈 0.05 ）. The expression of MTH2 in thymuses of SAMP8 and SAMR1 had the same trend with aging （P 〈 0.05）. Conclusion The age - related de- cline of MTH2 and MTH3 in thymuses of SAM mice reveals that these two proteins play an important role in the aging process of thymus, especially, the decrease of MTH3 expression may be tightly associated with the rapid thymus aging, in SAMP8 mice.