Drebrins和Icam-5在Fmr-1基因敲除鼠大脑皮层的表达和意义

Expressions of Drebrins and Icam-5 in mouse cerebral cortex with Fmr-I gene knockout and their significance in fragile X syndrome

目的观察脆性X综合征（FXS）模型小鼠不同发育时期大脑皮层中DrebrinA、DrebrinE及Icam．5 mRNA水平变化情况及意义。方法应用荧光实时定量PCR（RT．PCR）法检测Fmr-1基因敲除K0小鼠及野生健康对照小鼠出生后第7天、第14天、第21天和第28天大脑皮层DrebrinA、Drebrin E及Icam-5 mRNA的表达（4≤n≤10）。结果KO组小鼠出生后第14天Drebrin A mRNA水平较健康对照组小鼠明显降低，而同时间DrebrinEmRNA水平较健康对照组小鼠明显增高，差异均有统计学意义（P〈0．05）；KO组小鼠Icam-5 mRNA水平在出生后第14和21天均明显高于健康对照组，差异均有统计学意义（P〈0．05）。结论DrebrinA和Drebrin E在大脑皮层发育期的表达交替延迟及Icam．5的一过性过度表达是FXS智力低下的原因之一。

Objective To investigate and compare the changes of Drebrin A, Drebrin E and Icam-5 mRNA levels in the cerebral cortex of Fmr-1 gene knockout mouse during brain development periods. Methods Fmr-1 gene knockout （KO） male mice and their wild type （WT） counterparts were chosen in our experiment （4 ≤ n ≤ 10）; the levels of target mRNAs were detected by real time quantitative PCR; check points were set on the 7^th, 14^th, 21^th and 28^th postnatal d. Results The mRNA level of Drebrin A in the KO group was significantly lower than that in the WT group on the 14^th postnatal d, while that of Drebrin E was significantly higher than that in the WT group （P〈0.05）. The mRNA level of Ieam-5 in the KO group was significantly higher than that in the WT group on the 14~ and 21^th postnatal d （P〈0.05）. Conclusion The delayed shift ofDrebrin A to Drebrin E and transitional over-expression of Icam-5 in developmental cerebral cortex are the reasons for mental retardation in Fragile X Syndrome.