放射线对嗅黏膜的损伤及嗅功能的影响

当前放射治疗已成为头颈部恶性肿瘤综合治疗的重要手段之一,放射线作用于嗅黏膜后可导致嗅黏膜充血、水肿、血管闭锁、局部组织纤维化、嗅感觉神经元凋亡与再生失衡及其周围环境改变等.上述结构的破坏必然影响正常的嗅功能,导致嗅感受阈、识别阈的升高,但嗅觉的损伤尚可获得有限的恢复,且其损伤的程度还可能与放射线的剂量有关.本文综述r放射线对嗅黏膜的损伤及嗅功能的影响,并分析放射治疗导致嗅觉障碍的可能机制.     

流感病毒感染后小鼠嗅感觉神经元的凋亡与再生

目的 研究病毒感染后小鼠嗅感觉神经元的凋亡和再生，探讨病毒感染后嗅觉障碍(PVOD)的发病机制。方法 经前鼻孔接种流感病毒，感染实验动物的鼻腔；TUNEL技术检测嗅感觉神经元凋亡；BrdU掺入单克隆抗体标记技术检测基底细胞增殖。结果 ①流感病毒感染后嗅感觉神经元凋亡显著增多，恢复期凋亡细胞逐渐减少。②基底细胞增殖早期有所增多，随后减少至和凋亡细胞相当的水平。结论 流感病毒感染可有效地诱导嗅感觉神经元凋亡，并促进基底细胞增殖；基底细胞增殖不足以补充嗅感觉神经元凋亡，导致嗅感觉神经元总数减少。     

凋亡相关蛋白Bcl-2和Bax在慢性鼻及鼻窦炎伴嗅觉障碍患者嗅黏膜中的表达

目的研究Bcl-2和Bax在慢性鼻及鼻窦炎（CRS）伴嗅觉障碍患者嗅黏膜中的表达,探讨其对嗅觉神经元（olfactory receptor neurons,ORNs）凋亡的调节作用。方法采用康涅狄格化学感受临床研究中心所采用的嗅觉检查法——CCCRC（Connecticut ChemosensoryClinical Research Center）对46例行功能性鼻内镜手术的患者进行嗅觉评分并分组：A组,CRS伴嗅觉障碍25例;B组,CRS不伴嗅觉障碍10例;C组,单纯鼻中隔偏曲行鼻中隔矫正术11例。免疫组织化学方法检测Bcl-2、Bax在3组患者嗅黏膜中的表达。结果在ORNs中,A组Bcl-2和Bax表达显著高于B组（q=3.24、4.29,P均〈0.05）和C组（q=8.56、12.99,P均〈0.01）,A组Bcl-2/Bax比值显著低于B组（q=3.76,P〈0.05）和C组（q=6.67,P〈0.01）;在基底细胞中,Bcl-2在3组表达无显著差异（q=0.68、0.69、1.06,P均〉0.05）,Bax在A组的表达显著高于B组和C组（q=9.54、11.98,P均〈0.01）,A组Bcl-2/Bax比值显著低于B组和C组（q=5.48、9.14,P均〈0.01）;在A、B、C 3组ORNs和基底细胞中,Bcl-2/Bax比值与嗅觉评分均呈正相关（rA分别为0.5631、0.8926,rB分别为0.5700、0.7991、rC分别为0.5694、0.8121,P均〈0.01）。结论细胞凋亡参与了CRS伴嗅觉障碍患者ORNs的减少,Bcl-2和Bax在此过程中起了重要的调控作用,Bcl-2/Bax比值决定细胞是否凋亡。     

慢性鼻窦炎鼻息肉失嗅症患者嗅上皮细胞凋亡及相关基因BCL-2,BAX的表达

目的探讨慢性鼻窦炎鼻息肉失嗅症患者嗅上皮中细胞凋亡和BCL-2,BAX基因的表达.方法用免疫组化S-P法测定28例慢性鼻窦炎鼻息肉失嗅症患者嗅上皮和10例正常对照组嗅上皮凋亡抑制基因BCL-2,凋亡促进基因BAX的表达;同时应用dUTP缺口末端标志法(TUNEL法)测定上述两种组织中细胞原位的凋亡.结果(1)慢性鼻窦炎鼻息肉失嗅症组嗅上皮中BCL-2,BAX表达显著高于嗅觉正常组(P<0.05),但是,嗅觉障碍组嗅上皮中BAX表达显著高于BCL-2(P<0.05);(2)失嗅症组嗅上皮中细胞凋亡指数(AI)高于嗅觉正常组(P<0.05).结论慢性鼻窦炎鼻息肉嗅上皮细胞凋亡显著,BCL-2和BAX在此过程中起了重要的调控作用.     

嗅感觉神经元的再生调控及与嗅觉障碍的关系

嗅感觉神经元（olfactory receptor neurons，ORNs）在嗅觉中有重要的作用，且能够不断更新。ORNs的干细胞存在于嗅上皮的球形基底细胞中，ORNs的前体分为三个阶段，每个阶段都是ORNs产生的重要调控点。而对ORNs的调控分子信号主要为两个多肽类生长因子的超家族，这些分子信号对ORNs的再生和保持嗅上皮中适当数量的ORNs都有重要作用。了解ORNs再生的调控机制，研究促进ORNs的再生．可为治疗嗅觉障碍提供一些有效的方法。     

慢性鼻窦炎嗅觉障碍患者嗅上皮超微结构观察

目的观察慢性鼻窦炎嗅觉障碍患者嗅上皮的超微结构变化。方法对35例住院行鼻内窥镜手术治疗伴有嗅觉缺失鼻窦炎患者的嗅上皮取活体组织,光镜下将嗅上皮按病变分为正常、萎缩和呼吸上皮化生组,透射电镜分别观察各组超微结构变化。结果①光镜下正常的嗅上皮细胞表面超微结构出现支持细胞微绒毛消失、嗅泡内微管结构消失或空泡化致嗅泡变形、嗅纤毛变形或减少、少量纤毛化生等改变;②萎缩的嗅上皮超微结构改变的特点轻、中度萎缩主要为支持细胞上部的细胞器和膜限制性的电子致密囊泡明显减少或消失、空泡化,基底细胞退行性变;重度萎缩为细胞结构不清,多为双层细胞结构,细胞核染色质呈斑块状凝聚、核空泡化或核固缩;细胞质内均出现内质网扩张,线粒体肿胀、嵴排列紊乱、减少或空泡状改变;③呼吸上皮化生区域,丛状纤毛细胞与支持细胞、嗅泡样结构间隔分布,即嗅上皮细胞呈岛状分布。结论炎症导致嗅上皮细胞由表层及里层各种超微结构异常程度与嗅上皮萎缩程度呈正相关;慢性鼻窦炎嗅觉障碍患者嗅上皮超微结构变化与分型分期无关。     

慢性鼻窦炎嗅觉障碍患者嗅上皮超微结构观察

目的 观察慢性鼻窦炎嗅觉障碍患者 嗅上皮的超微结构变化。方法 对35例住院行鼻内窥镜手术治疗伴有嗅觉缺失鼻窦炎患者的嗅上皮取活体组织,光镜下将嗅上皮按病变分为正常、萎缩和呼吸上皮化生组,透射电镜分别观察各组超微结构变化。结果 ①光镜下正常的嗅上皮细胞表面超微结构出现支持细胞微绒毛消失、嗅泡内微管结构消失或空泡化 致泡变形、嗅纤毛变形或减少、少量纤毛化生等改变;②萎缩的嗅上皮超微结构改变的特点：轻、中度萎缩主要为支持细胞上部的细胞器和膜限制性的电子致密囊泡明显减少或消失、空泡化,基底细胞退行性变;重度萎缩为细胞结构不清,多为双层细胞结构,细胞核染色质呈斑块状凝聚、核空泡化或核固缩;细胞质内均出现内质网扩张,线粒体肿胀、嵴排列紊乱 、 减少或空泡状改变;③呼吸上皮化生区域,丛状纤毛细胞与支持细胞、嗅泡样结构间隔分布,即嗅上皮细胞呈岛状分布。结论 炎症导致嗅上皮细胞由表层及里层各种超微结构异常程度与嗅上皮萎缩程度呈正相关;慢性鼻窦炎嗅觉障碍患者嗅上皮超微结构变化与分型分期无关。     

慢性鼻窦炎嗅觉障碍的嗅粘膜病理学观察

目的观察慢性鼻窦炎嗅觉障碍患者的嗅粘膜病理变化及其与嗅觉障碍的治疗和预后的关系。方法对２３例住院行鼻内窥镜手术治疗的鼻窦炎患者的嗅粘膜进行了组织学观察。术前嗅觉检查均为嗅觉缺失，失嗅时间５～３０年，平均１１．８年。男１５例，女８例，年龄２６～７１岁，平均４８岁。结果２３例（２３侧）嗅粘膜均发现有病理组织学的改变，其中程度不等的嗅上皮萎缩１０侧次（４３．５％），程度不等的嗅细胞减少１６侧次（６９．６％），呼吸上皮化生６侧次（２６．１％），嗅腺粘液腺化生１０侧次（４３．５％）。术后随访２～６个月，嗅觉恢复或改善者１６例（６９．６％），为嗅上皮正常或轻中度病变者。嗅觉无变化７例（３０．４％），为嗅上皮中重度或重度病变者。结论嗅上皮病变程度与术后嗅觉恢复程度成正相关，嗅细胞的数量减少越明显，嗅觉障碍治疗的预后越差。     

鼻内镜治疗慢性鼻窦炎嗅觉障碍的临床病理学研究

目的探讨鼻内镜治疗慢性鼻窦炎嗅觉障碍的临床疗效与嗅黏膜病理学变化的关系。方法对52例(104侧)嗅觉障碍病人行功能性鼻内镜手术(FESS),同时辅助药物治疗,并对治疗前后嗅黏膜进行了组织学观察及统计学分析。结果104侧嗅黏膜术前均发现有病理组织学的改变,以嗅细胞的减少占首位,为73%(73/100);其次是嗅上皮萎缩,为49%(49/100);4侧呼吸上皮化生。Ⅰ型与Ⅱ型相比术前嗅细胞减少、嗅上皮萎缩,差异有统计学意义(P<0.05)。术后随访6个月,嗅觉恢复66.3%,嗅觉改善23.1%,为嗅上皮正常或轻中度病变者;嗅觉无变化10.6%,为嗅上皮中重度病变和呼吸上皮化生者。各临床分型于术前、术后在嗅细胞减少、嗅上皮萎缩,差异有统计学意义(P<0.01)。结论慢性鼻窦炎分型与嗅上皮病理学变化明显相关,嗅细胞减少、嗅上皮萎缩是嗅觉障碍的病理学基础,鼻内镜技术是治疗嗅觉障碍的有效方法,药物治疗明显提高疗效。     

鼻息肉上皮细胞增殖活性和凋亡活性的比较

目的 探讨鼻息肉上皮细胞增殖和凋亡平衡状态及其发病学意义。方法 实验组（鼻息肉组）29例,对照组（下鼻甲组）11例,采用免疫组化染色法检测增殖细胞核抗原（proliferation cell nuclear antigen, PCNA）的表达。采用TUNEL过氧化酶原位标记法检测原位细胞凋亡。结果 ①鼻息肉上皮PCNA 阳性细胞指数（PIPCNA）和凋亡细胞指数（AI）均大于下鼻甲（30.02±5.89,5.33±2.79）(两者P＜0.01),但鼻息肉上皮PIPCNA/AI值（1.95±0.66）小于下鼻甲（6.93±3.32）(P＜0.01)。②鼻息肉上皮PIPCNA（53.60±11.10） 大于AI（29.48±8.20）(P＜0.01)。结论 鼻息肉上皮细胞增殖活性和凋亡活性均增强,凋亡活性增强幅度较大,但总的来说,鼻息肉上皮细胞增殖率仍然大于细胞凋亡率,细胞累积增多,导致了鼻息肉上皮细胞的过度增殖。     

大鼠嗅感觉上皮发育及嗅细胞凋亡的研究

目的 探讨神经特异性烯醇酶（NSE）、嗅细胞标记蛋白（OMP）及细胞凋亡在不同胎龄大鼠嗅黏膜中的表达。方法 免疫组化方法检测NSE及OMP在不同孕期大鼠嗅上皮中的表达及其规律。TUNEL方法检测不同孕期大鼠嗅上皮中凋亡细胞并计算细胞凋亡指数（AI）。结果 E13d鼻腔黏膜中即有NSE阳性表达,细胞数量多。E13d嗅上皮中未见OMP阳性表达细胞。在E14d,嗅上皮中出现嗅OMP阳性细胞,数量少,随胎龄增加阳性细胞数量增多,至17d达高峰并逐渐趋于稳定。E13～E15d细胞凋亡数量较稳定,至E16d凋亡细胞数量明显增加,达到高峰,E18～E21d凋亡细胞数量逐渐减少渐趋于稳定。E16dAI与其他d数差异有统计学意义。结论 E14d嗅黏膜中已有发育成熟的嗅细胞,数量少,胚胎发育后期大鼠嗅化学感受器发育已趋于成熟。在嗅上皮发育过程中存在细胞凋亡,E16d嗅细胞凋亡出现一高峰,细胞凋亡在嗅觉发育过程中起重要作用。     

Pathogenetic mechanism of olfactory cell injury after exposure to sulfur dioxide in mice

OBJECTIVES: This study aimed to investigate the cellular pathogenetic mechanism involved in olfactory tissue injury and regeneration. STUDY DESIGN: Adult male mice were exposed to 40 ppm SO2 for 2 hours. METHODS: The mice were sacrificed immediately, 4 hours, and 1, 3, 5, 7, 10, 14, and 21 days after exposure to SO2. Olfactory neuroepithelium and bulbs were harvested at the time of sacrifice. Western blot and immunohistochemical staining were performed. RESULTS: Injuries of the olfactory neuroepithelium were found 24 hours after exposure to SO2. The number of total olfactory neuroepithelial cells decreased after SO2 exposure and recovered after 3 weeks. In contrast, the number of proliferating cell nuclear antigen (PCNA)-positive cells increased after SO2 injury and then decreased. In the neuroepithelium, where PCNA expression increased, olfactory marker protein (OMP)-positive cells were sparse. The expression of inducible nitric oxide synthase (iNOS) was localized in the lateral half of the turbinates. However, there was no expression of iNOS in the medial half of the turbinates, in which PCNA was strongly expressed. There was increased immunoreactivity of neuronal NOS (nNOS) in the surviving cells after SO2 exposure. Immediately after exposure to SO2, the immunoreactivity to phosphorylated fraction of extracellular signal-regulated kinases (phospho-ERK)-1/2 increased in the cytoplasm and nucleus of supporting cells. In Western blot analysis, nNOS expression increased 4 hours after SO2 exposure. CONCLUSIONS: These findings suggest that the regenerative activity of the neuroepithelium might be well demonstrated by PCNA immunoreactivity and that regeneration of the neuroepithelium can be activated several days after SO2 injury. The two NOS isoforms, iNOS and nNOS, might contribute to neuroprotection in the olfactory neuroepithelium.     

Impaired olfactory function in mice with allergic rhinitis

Objective

It has been reported that olfactory function is impaired in patients with allergic rhinitis. However, the mechanism of olfactory dysfunction in allergic rhinitis remains poorly understood. Because of difficulties in obtaining and analyzing human olfactory mucosa due to both technical and ethical issues, an animal model needs to be established to clarify the mechanism of olfactory dysfunction in allergic rhinitis. The purpose of this study was to study olfactory function and changes in olfactory mucosa using allergic rhinitis mice.

Methods

A model of allergic rhinitis mice with olfactory dysfunction was developed by sensitizing with ovalbumin (OVA), and intranasally challenging with the same allergen. Olfactory function of mice with or without allergic rhinitis was assessed by odor detection ability test with cycloheximide and local field potential (LFP) with 1-octanal. We also evaluated histological changes in the olfactory mucosa of allergic rhinitis mice by both light and electron microscopy.

Results

Both of odor detection ability test and LFP showed that olfactory function was impaired in mice with allergic rhinitis, but not in mice without allergic rhinitis. Histopathological findings showed prominent infiltration of eosinophils, plasma cells, neutrophils, mast cells, and macrophages in lamina propria of olfactory mucosa of mice with allergic rhinitis, although infiltration of these cells was not seen in control mice. Allergic rhinitis also increased the number and size of glands in olfactory mucosa, suggesting an elevated amount of mucin in olfactory mucosa.

Conclusion

This study showed for the first time that mice with allergic rhinitis have impaired olfactory function, increased size and number of olfactory glands, and infiltration of eosinophils, neutrophils, mast cells, plasma cells, and macrophages in the olfactory mucosa. This suggests that allergic reactions are seen in olfactory mucosa of mice with allergic rhinitis, and that greater olfactory gland activity is associated with olfactory dysfunction. Also, this mouse model could provide an expedient system for analyzing mechanisms of olfactory dysfunction.     

嗅神经切断术后白血病抑制因子在嗅上皮中的表达

目的分析白血病抑制因子(leukemiainhibi-toryfactor,LIF)与嗅感觉神经元(olfactoryreceptorneurons,ORNs)再生的关系。方法建立嗅神经切断的小鼠动物模型,在术后8小时、2天、3天和5天分别通过免疫组化和相对半定量RT-PCR的方法,在蛋白和mRNA水平观察LIF及其特异性受体LIF-R在嗅上皮中的表达情况。结果LIF和LIF-R的表达都是在术后8小时迅速、一过性地上升,随后又迅速恢复至对照组水平。LIF由残留的ORNs表达,LIF-R则由基底细胞和嗅鞘细胞(olfactoryensheathingcells,OECs)表达。结论LIF是在ORNs凋亡再生机制中较早表达的一种细胞因子,凋亡中的ORNs产生并分泌的LIF作用于基底细胞和嗅鞘细胞,从而启动调节ORNs再生的一系列分子机制。     

Immunohistochemical method for the diagnosis of olfactory disturbance

To confirm the diagnosis and determine the cause of the olfactory disturbance, we used an immunohistochemical method to examine biopsy specimens of the olfactory mucosa from a patient who complained of anosmia after head injury. Neuron-specific enolase immunoreactivity was found in the olfactory vesicles and dendrites of the receptor cells in the olfactory epithelium. S-100 protein immunoreactivity was found in the ductal cells of Bowman's gland in the olfactory epithelium and in the acinar cells of Bowman's gland in the lamina propria. This suggests that the olfactory receptor cells and Bowman's gland were normal. The olfactory disturbance in this patient was not caused by nerve transection due to the head injury, but by already existing chronic sinusitis. Immunohistochemical methods are useful for diagnosing olfactory disturbance when used in combination with biopsy of olfactory mucosa.     

Transplantation of Neural Stem Cells in Anosmic Mice

Objectives

Treating olfactory dysfunction is a challenge for physicians. One of the therapeutic options could be transplantation of stem cells. In this study, neural stem cells were transplanted into anosmic mice.

Methods

Neural stem cells were generated from the olfactory bulb of green fluorescent protein (GFP)-transgenic C57BL6 mice. Anosmia were induced by injection of intraperitoneal 3-methylindole. The neural stem cells were transplanted transnasally on the next day. The olfactory function was evaluated by a food-finding test once a week. The olfactory neuroepithelium was harvested for histologic examination and protein analysis at 4 weeks.

Results

Twenty-five percent (6/24) of the control mice that were not transplanted with neural stem cells survived at 4 weeks while 67% (8/12) of the transplanted mice survived (P=0.029). The food finding test showed that the transplanted mice resumed finding food at 3 weeks while the control mice resumed finding food at 4 weeks. GFP-positive cells were observed in the olfactory neuroepithelium of the transplanted mice. Western blotting revealed that the olfactory marker protein expression was significantly lower in the control mice than that in the transplanted mice.

Conclusion

This study demonstrated that improvement of mouse survival was achieved and recovery of olfactory function was promoted by transnasal transplantation of neural stem cells in the anosmic mouse model. These results indicate that stem cells might be one of the future modalities for treating olfactory impairment.     

反义表皮生长因子受体纳米颗粒对小鼠头颈鳞状细胞癌放疗增敏的实验

目的应用反义表皮生长因子受体（epidermal growth factor receptor,EGFR）纳米颗粒,研究阻断EGFR表达,对小鼠头颈部鳞状细胞癌（简称头颈鳞癌）敏感性的作用。方法载反义EGFR寡核苷酸纳米颗粒转染SCC VII细胞株,通过Western—blot研究其蛋白抑制效应。放射治疗千预后,细胞克隆试验和MTT试验检测细胞的放射敏感性,流式细胞仪检测细胞周期分布和凋亡情况：构建小鼠头颈癌荷瘤模型,瘤体注射反义EGFR纳米颗粒,予以4Gy放射治疗,观察肿瘤生长抑制情况。结果反义EGFR纳米颗粒明显抑制EGFR蛋白的表达情况：反义EGFR纳米颗粒与放疗联合降低了肿瘤细胞克隆形成能力及生长能力（P〈0．05）：肿瘤细胞发生G1期阻滞,细胞凋亡率增加（P〈0．05）。体内实验发现反义EGFR纳米颗粒组肿瘤生长明显延缓。结论反义EGFR纳米颗粒通过下调EGFR的表达,使SCC VII细胞发生G1期阻滞,具有放疗增敏效应。     

Evaluation of turnover of olfactory epithelium in mice by using anti-BrdU monoclonal antibody

Among nerve cells of vertebrates, the olfactory elements are uncommon in their capacity to turnover and to be replaced after injury. An autoradiographical and morphological observation has shown that degenerated olfactory nerve cells are reconstituted by a new population of neurons which originate from basal cells. However, an autoradiographic method requires a special isotope institute and it takes a long time for the final specimen to observe. Recently, a rapid technique without the radioisotope has been alternatively developed in which a thymidine analogue, 5-bromo-2'-deoxyuridine (BrdU), is incorporated into replicating DNA and subsequently localized using a specific monoclonal antibody. In the present study, cell dynamics of olfactory mucosa in mice were investigated by means of immunohistological technique. The results were as follows. 1. The labelled elements were concentrated at the basal layer of the epithelium, which were observed 5 hrs after the first injection of BrdU. 2. At 15 days after administration of BrdU, the labelled elements were located in the mid-layer of the epithelium, where can be recognized as the compartment of nerve cells. 3. After 30 days, the labelled cells disappeared from the epithelium. It indicates that the period of turnover in the olfactory epithelium of mice is within 30 days. 4. Fifteen days after axotomy of the olfactory nerves, two stained patterns which were numerously or sparsely labelled regions were observed. The former is considered that immature neurons predominantly exist, and the latter is the area which mature neurons abundantly locate. It is considered that this immunohistological approach is useful for the observation of the turnover of the olfactory epithelium.     

Age-related olfactory dysfunction: cellular and molecular characterization in the rat

BACKGROUND: Olfactory receptor neurons (ORNs) undergo apoptosis at a baseline rate even in the absence of obvious disease. Although the precise triggers of the apoptotic cascade are unclear, ORNs are exposed directly to the external environment, making them susceptible to injury. As an adaptive mechanism, mammals have the ability to replace lost ORNs throughout adult life from neuronal precursors within the olfactory epithelium (OE). In humans, this process fails with age as the surface area of the OE and the number of ORNs decline, coupled with a loss of clinical olfactory function. The question addressed in this study is whether this age-related failure of olfactory sensation is a result of a decrease in neuronal proliferation or an increase in ORN cell death. METHODS: To begin to address this question the ribonuclease protection assay was used to assess expression of apoptosis-related genes in rat OE as a function of age. Second, the terminal deoxynucleotide transferase end labeling assay was used to assess the percentage of ORNs undergoing apoptosis (apoptotic index) in three groups of animals: young (12 weeks), old (32 months), and bulbectomized rats. Bulbectomy is a standard model for ORN injury associated with a massive increase in ORN apoptosis and serves as a positive control. RESULTS: Ribonuclease protection assay data indicate an age-related increase in Bax, Bcl-xL, and procaspase-3 messenger RNA expression in aged compared with young rats. A similar but more pronounced increase in expression of these apoptotic-related genes is seen after bulbectomy. The terminal deoxynucleotide transferase end labeling assay also showed a statistically significant increase in the apoptotic index with both age and bulbectomy. CONCLUSION: Taken together, the current results indicate that aging and injury induce parallel changes in OE. Furthermore, these findings support the hypothesis that age-related olfactory dysfunction is, at least in part, related to an increase in ORN cell death.     

神经元核心抗原在小鼠嗅球和嗅上皮发育中的表达

目的：探讨神经元核心抗原（NeuN）在嗅球和嗅上皮发育过程中的表达特性和意义。方法：在小鼠胚胎发育9．5、11．5、14．5、17．5d,出生当天和3个月成年个体的头部切片标本中,以免疫荧光染色方法检测NeuN的表达。结果：刚出生小鼠嗅球内层状结构尚不明显,NeuN表达于嗅球周边区域。在3个月大成年小鼠,嗅球的层状结构已清晰可见,NeuN表达阳性的成熟神经元主要聚集于接近嗅球中心的颗粒细胞层。位于嗅上皮的双极嗅感觉神经元在小鼠胚胎和成年个体中均未见NeuN表达。结论：NeuN通常被认为表达于几乎所有部位的成熟神经元。但在嗅球和嗅上皮中,NeuN只表达于成熟嗅球中的颗粒细胞层。小鼠出生到发育为成熟个体的过程中,NeuN表达阳性的成熟神经细胞由周边逐渐向嗅球中心迁移,可能与气味模式的形成有关。