Effect of offactory bulb lesion on proliferation, migration and differentiation of neural stem cells in subventricular zone

Abstract

Objective To detect the effect of olfactory bulb(OB)lesion on proliferation,migration and differentiation of the neural stem cells(NSCs)in the subventricular zone(SVZ).Methods Forty-two healthy female SD rats were enrolled and randomly divided into normal control group,isotonic saline group and OB lesion at day 3,at weeks 1,2,3 and 4 groups,six rats per group.OB lesion was induced by N-methyl-D-aspartic acid(NMDA)injection.Bromodeoxyuridine(BrdU)was injected intraperitoneally to label NSCs.Immunohistochemical staining was used to detect the proliferation of SVZ NSCs.In addition,another 18 rats were randomly divided into normal control group,isotonic saline group and lesion group,six rats per group.BrdU was injected intraperitoneally one week after OB lesion and then the animals were sacrificed four weeks after BrdU injection to detect the migration and differentiation of NSCs with immunohistochemistry and immunofluorescence.Results Three days after OB lesion,BrdU-positive cells in SVZ began to increase(26.33 ± 2.58,P ＜0.01),reached the maximum at week 1 (35.33 +3.01,P＜0.01)and still sustained a high level at week 4(19.50+ 2.26,P＞0.05).Five weeks after the OB lesion,the rostral migratory-stream(RMS)and the BrdU-positive cells in OB were significantly increased(86.50 + 5.09,P ＜ 0.01)and(52.83 + 3.87,P ＜ 0.01),respectively.By using fluorescence double staining,most of the BrdU-positive cells were co-localized with the neuronal nuclear antigen(Neun),with a portion of BrdU-positive cells expressing the glial fibrillary acidic protein (GFAP).Conclusions OB lesion can improve the proliferation of NSCs in SVZ and migration of NSCs to OB.The newborn cells can differentiate into not only neurons,but also gliocytes and may be involved in lesion repair. Key words: Olfactory bulb; Neural stem cell; Cell proliferation; Rats