早期应激对小鼠纹状体神经元发育的影响

Effects of early-life stress on the development of the striatal neurons of mouse

目的探讨早期应激对背侧纹状体多棘神经元发育的影响。方法通过改变新生小鼠（出生后第2～9天）的生长环境建立早期应激动物模型,采用原位杂交、Golgi染色和体视学分析方法,定量分析应激小鼠背内侧纹状体和背外侧纹状体内神经元胞体、树突和树突棘的改变。结果 9d龄C57BL/6J小鼠的纹状体神经元含丰富的树突分支和树突棘。持续7d的应激主要影响背外侧纹状体,表现为纹状体神经元的近胞体树突分支增多（应激组9.50±0.38,n=8;对照组6.50±0.23,n=6;P〈0.05）,树突分支上含大量丝状伪足（每20μm树突节段：应激组8.15±0.51,n=8;对照组3.85±0.33,n=6;P〈0.05）,但树突棘数量减少（每20μm树突节段：应激组12.05±0.91,n=8;对照组20.02±0.73,n=6;P〈0.05）。结论早期应激主要干扰背外侧纹状体神经元树突的发育,导致树突棘的成熟延缓。

Objective To study the impact of early-life stress on the development of spiny neurons in the dorsal striatum. Methods The early-life stress animal model was created by changing the growth environment of new born mouse pups from postnatal day（ P） 2 to P 9（ P2-P9）. The in situ hybridization,Golgi staining,and stereological analysis were employed to investigate the effect of stress on the soma,dendritic branches,and spines of striatal neurons. Results The striatal neurons in P9 C57 BL /6J contained numerous dendritic branches and spines. Stress from P2 to P9 particularly affected the striatal neurons in the dorsolateral region,leading to abundant proximal dendritic branches（ 9. 50 ± 0. 38 vs6. 50 ± 0. 23,n = 6-8,P〈0. 05）,and increased number of filopodia（ 8. 15 ± 0. 51 vs 3. 85 ± 0. 33 per 20 μm dendritic segment,n = 6-8,P〈0. 05）,but reduced dendritic spines（ 12. 05 ± 0. 91 vs 20. 02 ± 0. 73 per 20 μm dendritic segment,n = 6-8,P〈0. 05）. Conclusion Early-life stress interrupted the dendritic differentiation and postponed the maturation of spines of striatal neurons in the dorsolateral striatum.