胚胎干细胞在阿尔茨海默病小鼠中的移植研究

目的 观察胚胎干细胞移植至AD小鼠脑内后的分化情况和小鼠学习、记忆能力变化情况.方法 C57BL/6AD小鼠按随机数字表法分4组:(1)痴呆组(n=14),采用Ibotenic毁损右侧基底巨细胞核(NBM);(2)假手术组(n=14),于右侧NBM注射PBS;(3)移植组(n=12),于NBM毁损后4周移植胚胎干细胞;(4)正常对照组(n=14),不作任何处理.移植组额叶和顶叶皮质移植小鼠胚胎干细胞,术后12周应用HE染色和HuC/D-绿色荧光蛋白、GFAP-绿色荧光蛋白免疫双标染色观察胚胎干细胞的分化情况,以8方向迷宫评价小鼠的学习、记忆变化情况.结果 HE染色结果显示,各移植点胚胎干细胞均发展为恶性畸胎瘤,以额叶部位最为巨大;免疫双标染色未见HuC/D、GFPA表达.痴呆组小鼠的工作记忆错误(WME)值较正常对照组明显升高,比较差异有统计学意义(t=6.130,P=0.000).而移植组小鼠的WME值又较痴呆组小鼠明显升高,比较差异有统计学意义(t=6.460,P=0.000).各组小鼠的参考记忆错误(RWE)值差异无统计学意义(F=0.144,P=0.065).结论 胚胎干细胞移植至AD小鼠脑内移植未分化为神经元或胶质细胞,相反均发展为恶性畸胎瘤,小鼠的近事记忆损害明显加重.

Embryonic stem cell transplantation in the cortex of mouse models of Alzheimer's disease

Objective To elucidate the differentiation of embryonic stem cells (ESCs) after their transplantation into mouse models of Alzheimer's disease (AD), and observe the changes of learning and memory abilities of the mice. Methods The C57BL/6 AD mice were randomly divided into 4 groups:dementia group (n=14), enjoying the dementia in the mouse models of right nucleus basalis of Meynert (NBM) lesion destroyed by Ibotenic; sham-operated group (n=14), injecting PBS in the right NBM;transplantation group (n=12), enjoying the dementia in the mouse models of right NBM lesion destroyed by Ibotenic and performing transplantation with ESCs in the frontal and parietal cortices; and normal control group (n=12), without giving any treatment. Behavioral tests by eight-arm radial maze were conducted to evaluate the changes of learning and memory abilities of the mice 12 weeks after the transplantation. HE staining and double staining of HuC/D-green fluorescent protein (GFP) and glial fibrillary acid protein (GFAP)-GFP were performed to observe the differentiation of ESCs in the cortices 12 weeks after their transplantation. Results It was demonstrated by HE staining that the ESCs transplanted into the cortices developed into malignant teratoma in all AD mice and the frontal lobe had the largest one;no expressions of HuC/D and GFPA were noted. The value of working memory error (WME) in mice of the dementia group was significantly higher than that in the normal controls (t=6.130,P=0.000), while the WME value in the mice of transplantation group was obviously higher than that in the mice of dementia group (t=6.460, P=0.000). The value of reference memory error between each 2 groups was not significantly different (F=0.144, P=0.065). Conclusion ESCs transplanted into the frontal and parietal cortices cannot be differentiated into neurons or glias but into tetratoma, and recent memory disruption of AD mice even worsen.