人脐带间充质干细胞移植对老年痴呆小鼠脑、肝组织中衰老相关基因表达的影响

Effects of human umbilical cord mesenchymal stem cell transplantation on expression of aging related gene in brain and liver of Alzheimer's disease mice

目的:研究人脐带间充质干细胞(h UC-MSCs)静脉移植对APP+转基因鼠衰老的调控作用,并从衰老相关基因角度探讨MSCs延缓衰老的机制。方法:采用PCR技术对老年痴呆APP+转基因鼠进行分子鉴定;将传至第3代的h UC-MSCs细胞密度调整为1×106m L-1后进行尾静脉移植。移植h UC-MSCs 3周后,通过Morris水迷宫实验从行为学水平检测干细胞移植对APP+转基因鼠的延缓衰老作用(检测小鼠的学习记忆能力),然后采用荧光定量PCR和Western blot法检测h UC-MSCs移植后小鼠脑及肝脏组织中与衰老相关的基因及蛋白[沉默信息调节因子2(Sirt2)、增殖细胞核抗原(PCNA)、p16、p21、p53]表达的变化。结果:该实验共鉴定出12只APP+转基因鼠。与对照组相比,移植组小鼠逃避潜伏期时间明显缩短、穿越平台次数增加、在平台所在象限停留的时间延长,差异具有统计学意义(P均<0.05)。移植组APP+转基因鼠的脑及肝脏组织中PCNA和Sirt2基因的mRNA和蛋白相对表达量升高,p21及p53基因相对表达量降低(P均<0.05),而p16基因表达变化不明显(P>0.05)。结论:APP+转基因鼠经h UC-MSCs静脉移植治疗,学习记忆能力显著提高,延缓衰老作用明显,涉及衰老标志基因p21、p53、PCNA、Sirt2等表达调控改变,这些衰老标志基因之间相互联系,可能构成细胞衰老的基因调控链。

Aim： To research the anti-aging effects of human umbilical cord mesenchymal stem cells（ h UC-MSCs）transplantation on transgenic APP＋mice and to investigate the anti-aging mechanisms in terms of age-related genes.Methods： APP＋transgenic mice were identified by PCR.h UC-MSCs were isolated in vitro sterilely.At the third passage,single cell suspension at 1 × 10^6 m L^- 1was obtained and transplanted by tail venous pathway in the transplantation group.The anti-aging effects on transgenic APP＋mice were detected by Morris water maze test at three weeks after transplantation to study the learning and memory ability of the mice.qRT-PCR and Western blot were performed to test the change of mRNA and protein expression of age-related gene in the brain and liver of the APP＋mouse,including p16,p21,p53,silence information regulator 2（ Sirt2）,and proliferating cell nuclear antigen（ PCNA）.Results： 12 APP＋mice were identified totally.Compared with control group,the escaping latency was significantly shorter（ P〈 0.05）,the number of crossing platform quadrant increased and the time of crossing platform quadrant was significantly longer in the transplantation group（ P〈 0.05）.What＇s more,the expressions of Sirt2 and PCNA were increased,and p21,p53 but not p16 decreased in the brain and liver tissue of transplanted APP＋mice（ P〈 0.05）.Conclusion： The learning and memory ability and anti-aging effect are increased significantly in APP＋mice after h UC-MSCs tansplantation.The underlying mechanism is partly due to the change of aging related gene such as p21,p53,PCNA and Sirt2,which may interact with each other and constitute the gene regulation chain of cell aging.