鲑鱼鱼白DNA对小鼠胸腺作用的差异表达基因筛选

目的　探讨鲑鱼鱼白DNA(salmonmiltDNA ,SMD)对小鼠胸腺增龄性萎缩的作用及作用机制。方法　 10月龄雌性BALB/C小鼠按体重随机分为高剂量组 (333 33mg·kg-1·d-1)、低剂量组 (16 6 6 7mg·kg-1·d-1)和对照组 (0mg·kg-1·d-1)。喂饲 5周后 ,测定胸腺脏器指数 ;组织切片后以Image ProPlus专业图像分析系统 (4 0版 )进行胸腺细胞计数和皮质厚度测量 ,所得数据经SAS统计软件分析。应用基因芯片技术在对照组和高剂量组胸腺组织中筛选差异表达的基因片段、RT PCR鉴定部分片段。结果　SMD对小鼠的体重、胸腺重量和胸腺指数均无影响 ;高剂量组小鼠的胸腺皮、髓质细胞数量与对照组经统计学分析相比均显著增多 ;低剂量组的胸腺皮、髓质细胞数量与对照组相比经统计学分析差异均不显著 ;高、低剂量组的胸腺皮质平均厚度经统计学分析均显著高于对照组 ;经基因芯片技术初筛出 112条差异表达的基因片段 ;Genebank登录号为Aw2 0 910 2、U2 3789、X80 2 32的 3条上调表达的基因片段 ,经RT PCR鉴定 ,在高剂量组确实存在上调表达。结论SMD有通过促进细胞增殖相关基因的表达并同时促进发育、分化相关基因表达而逆转胸腺增龄性萎缩的可能。

Screening genes of differential expression in BALB/C mice thymus: a pilot study of effect of salmon milt DNA (SMD) on age-related involutions

OBJECTIVE: To investigate the effect and its mechanism of salmon milt DNA (SMD) on age-related involutions in mouse thymus. METHODS: Female BALB/C mice aged 10 months were divided randomly into three groups according to their weights. They were high dosage group (333.33 mg.kg(-1).b.w.d(-1)), low dosage group (166.67 mg.kg(-1).b.w.d(-1)) and control group (0 mg.kg(-1).b.w.d(-1)). After five weeks, their thymus indexes were measured and the thymocytes were counted and the thymus cortex thicknesses were also measured using Image-Pro Plus (version. 4.0) software in the thymus section. All the data were analyzed by SAS statistic software. Microarray technique was applied to screen the gene fragments, which were differentially expressed between the high dosage group and the control group, together with RT-PCR to further confirm some of them. RESULTS: No significant differences of the variables including body weight, thymus weight and thymus indexes among the three groups were found. The thymocytes quantities of thymus cortex and medulla in the high dosage group were significantly higher than those of the control group (P < 0.01 and P < 0.05, respectively). The thymus cortex thicknesses of both SMD supplement groups were significantly higher than that of the control group (P < 0.01 and P < 0.05 respectively). 112 differently expressed gene fragments were isolated. Furthermore, we found the fragments with the logged number of U23789, X80232 and Aw209102 were highly expressed in the high dosage group when RT-PCR technique was used. CONCLUSIONS: SMD may reverse the age-related involutions in mouse thymus via up-regulation the expression of proliferation related genes and via up-regulation the expression of development and differentiation related genes simultaneously.