Effects of olfactory bulb lesion on neural stem cells proliferation and expression of NMDA-receptor subunit 2B in the subventricular zone of rats

Abstract

Objective To investigate the effects of olfactory bulb(OB) lesion on neural stem cells proliferation and expression of NMDA receptor subunit 2B in subventricular zone(SVZ) of rats. Methods Sixty adult female SD rats were randomly divided into normal group, saline group and OB lesion group. OB lesion was induced by N-methyl-D-aspartic acid (NMDA) injection. Each group was respectively divided into four time points including 3 d, 7 d, 14 d and 28 d. Immunohistochemistry staining was used to detect the number of Nestin, Ki67 and NR2B-positive cells in the SVZ. Results (1)Nestin positive cells in the SVZ were shown at the different time of three groups.Seven days after OB lesion, IOD value of nestin-positive cells began to increase((29601±1788)/0.01 mm2, P<0.05), reached the maximum at 14 d((49800±3701)/0.01 mm2, P<0.05) and still sustained a high level at 28 day((27600±3209)/0.01 mm2, P<0.05). (2)Ki67 positive cells in the SVZ were shown at the different time of three groups.The number of Ki67-positive cells was increased significantly at 7 d, 14 d and 28 d after OB lesion compared to normal group and saline group (P<0.05). (3)NR2B immune expression in the SVZ was shown at the different time of three groups. The NR2B-positive cells increased at 3 d after OB lesion(58.80±2.95, P<0.05), reached the maximum at 14 d(68.40±4.04, P<0.05). At 28 d of OB lesion, the number of positive cells was reduced, but still sustained a high level(62.20±3.56, P<0.05). (4)The positive cells of NR2B and Ki67 were highly positive correlation at different time after OB lesion(r=0.968, P<0.05). Conclusions OB lesion can stimulate neural stem cell proliferation and increases the expression of NR2B. The increased mode of NR2B is in accordance with the schedule of the neural stem cells increase induced by OB lesion. Therefore, it indicates that the NMDA receptor subunit 2B may be involved in neural stem cell proliferation. Key words: Olfactory bulb; Subventricular zone; Neural stem cell; NMDA receptor