大鼠皮层神经元中磷酸化的细胞周期相关蛋白在发育过程中的表达

Expression of phosphorylated cell cycle related proteins in developing rat cortex

目的观察正常Wistar大鼠发育过程中皮层神经元的细胞周期相关蛋白及其磷酸化蛋白的表达,探讨发育过程中皮层神经元的细胞周期变化以及磷酸化细胞周期相关蛋白在其中的调控作用。方法采用免疫荧光方法观察不同发育时期CyclinD1、CDK2、P27以及磷酸化CDK2、磷酸化CDC2、磷酸化Rb表达的规律。结果在各年龄组NeuN阳性细胞数量随着年龄增加而逐渐减少。细胞周期相关蛋白(CyclinD1、CDK2、P27)在皮层神经元中广泛表达,各组间差异无显著性;磷酸化CDK2、磷酸化Rb阳性细胞的数量随着年龄增加而逐渐增多,各组间差异有显著性;磷酸化CDC2阳性细胞在各年龄组神经元中均无表达。结论随着年龄的增长,磷酸化CDK和Rb逐渐增多,使得进入细胞周期的皮层神经元增加。细胞周期相关蛋白的磷酸化调控作用可能与衰老时皮层神经元的凋亡有关。

[Objective] To observe the expression and the distribution of cell cycle related proteins and the activity of cyclin-dependent kinase （CDK） and the retinoblastoma tumor suppressor protein （Rb） in the developing rat cortex. [Methods] Immunofluorescent was used in staining for anti-CycinD1, anti-CDK2, anti-P27, anti-phospho-CDK2, anti-phospho-CDC2, anti-phospho-Rb and anti-NeuN antibodies to determine their expression and distribution in Wistar rat at different ages. [Results] There was strong expression of CyclinD1, CDK2, P27 in the brain tissue during the period from 1 d to 15 months. The positive expression of phospho-CDK2 and phospho-Rb increased while aging. There wag no positive expression of phospho-CDC2 in the cortex of all the five groups. [Conclusion] The expression of phospho- CDK2 and phospho-Rb suggests that differentiated neuron can re-enter the cell cycle and more neurons enter the cell cycle in the aged rat brain. Re-entering the cell cycle of differential neurons probably results in apoptosis.