嗅球切除对成年大鼠侧脑室外侧壁新生细胞增殖和分化的影响

INFLUENCE OF OLFACTORY BULB REMOVAL ON THE PROLIFERATION AND DIFFERENTIATION OF NEW NEURONS ORIGINATED FROM THE SUBVENTRICULAR ZONE OF ADULT RAT BRAIN

目的研究嗅球切除后成年大鼠侧脑室外侧壁(SVZ)新生细胞增殖和分化的情况,进一步探讨嗅球对SVZ神经生发活动的影响。方法建立成年SD雄性大鼠右侧嗅球切除模型,并分别存活4周和12周,利用Nissl染色、多唾液酸神经细胞黏附分子(PSA-NCAM)和BrdU免疫组织化学染色的方法观察了成年SD大鼠嗅球切除后存活不同时间两侧吻侧迁移流(RMS)BrdU阳性细胞数占总细胞百分比的变化以及两侧RMSPSA-NCAM阳性细胞的形态学变化。结果1·嗅球切除后不同时间点,嗅球切除侧RMS的细胞数增加,BrdU免疫阳性细胞数增加,但BrdU免疫阳性细胞数占总细胞数的百分比随嗅球切除后大鼠存活时间的延长而下降,且以RMS的吻侧部分下降更明显;2·嗅球切除后,在切除侧断端吻侧颗粒层和RMS均出现较对照侧更多的具有较长突起的PSA-NCAM阳性细胞。结论嗅球切除后仍有新生神经元沿RMS向吻侧迁移,但其增殖率随时间延长下调;嗅球的切除似乎并没有影响成神经细胞的分化。

Objective To explore the effect of olfactory bulb （OB） removal on neurogenesis in subventricular zone （SVZ） by observing the changes of proliferation and differentiation of new cells originated there. Methods An animal model of OB removal was created： Nissl staining and immunohistochemistry for showing the polysialylated form of the neural cell adhesion molecule （PSA-NCAM） and BrdU were done in the brain tissue from adult OB removal rats and observation was made under the light microscope. The total cell number and the number of PSA-NCAM and BrdU-positive cells on the two sides of RMS were counted and analyzed, and the morphological changes of PSA-NCAM-positive cells were observed. Results 1.The total cell number and the BrdU-positive cell number on the right side of the RMS in the rats with OB removal increased compared with those on the left side, but the percentage of the BrdU-positive cells decreased apparently with the operation delay after OB removal. 2. There were more PSA-NCAM-positive cells with long processes in the granular layer on the side of OB removal than those on the control side. In addition, some PSA-NCAM-positive cells with long processes were also observed in the RMS at the edge of the excision. Conclusion Young neurons still migrate along the RMS after the OB removal but the proliferation rate is downregulated. It seems that the OB removal has not affected the differentiation of neuroblastes originated in the SVZ.