背景:机体衰老时,各组织尤其是中枢神经组织中线粒体DNA发生突变,氧化磷酸化基因受损致线粒体功能下降已被证实,形态学上也会发生相应的改变。目的:对衰老和年轻大鼠嗅球内神经元的线粒体超微结构进行对比观察,分析衰老大鼠嗅觉障碍与嗅球内神经细胞线粒体改变的关系。设计:随机对照实验。单位:承德医学院附属医院内科,承德医学院电镜室。材料:实验于2002-04／12在承德医学院电镜室完成。雄性Wistar大鼠 16只,老龄组(>24个月)8只,体质量300-350 g;年轻组(6个月)8只, 体质量180-220 g。方法:两组大鼠给予质量浓度为10 g／L的乌拉坦1 g／kg腹腔内注射．麻醉后开胸,升主动脉插管,戊二醛与多聚甲醛混合固定液200 mL灌流固定,取嗅球,振荡切片,锇酸后固定,平板包埋,光镜下选取嗅球各层,制备超薄切片,透射电镜下对比观察。主要观察指标:①两组大鼠嗅球的分层。②两组嗅球主要神经元内的线粒体超微结构变化。结果:实验纳入大鼠16只,全部进入结果分析。①两组大鼠嗅球的分层:两组大鼠的嗅球分层均无明显改变,自外向内分别为嗅神经纤维层、团伞层、外丛状层、僧帽细胞层、内丛状层和嗅束神经纤维层。②两组嗅球主要神经元内的线粒体超微结构变化:老龄组刷状细胞线粒体较多,杆状或椭圆形,线粒体嵴不规则,局部排列紊乱,有的嵴断裂分解成细粒状,形成电子密度很高的固缩小体,少数线粒体成为不规则或同心圆形的髓鞘样小体。年轻组所有神经元的线粒体多为椭圆形,内、外层膜清晰可辨,线粒体嵴排列较均匀,不规则者偶见。结论:老龄大鼠的嗅球分层与年轻大鼠基本一致,但其嗅球内主要神经元的线粒体超微结构发生了明显变化,这与线粒体氧化磷酸化功能下降相一致,可能是导致老年嗅觉障碍的主要原因之一。 BACKGROUND: When the body senesce, mitochondrial DNA changes in various tissues, especially in the central nervous system. The mitochondrial function decline caused by oxidative phosphorylation gene damage has been confirmed and the morphological changes will also occur. OBJECTIVE: To compare the mitochondrial ultrastructure of neurons in the olfactory bulb of aging and young rats, and to analyze the relationship between the olfactory dysfunction and the changes of mitochondria in the olfactory bulb of the aging rats. Design: Randomized controlled experiment. Unit: Affiliated Hospital of Chengde Medical College, Department of Electron Microscope, Chengde Medical College. Materials: The experiment was performed at the electron microscope room of Chengde Medical College from April to December in 2002. Sixteen male Wistar rats aged 8 months (> 24 months) with a body weight of 300-350 g and 8 young adults (6 months) with a body weight of 180-220 g. Methods: Two groups of rats were injected intraperitoneally with 1 g / kg urethane at a concentration of 10 g / L. Anesthesia, thoracotomy, ascending aorta cannulation, glutaraldehyde and paraformaldehyde mixed fixed solution 200 mL fixed perfusion, take the olfactory bulb, the oscillation slice, osmium acid fixed, embedded in the plate, under the light microscope, the olfactory bulb layers were selected to prepare Ultrathin section and comparative observation under transmission electron microscope. MAIN OUTCOME MEASURES: ① The stratification of the olfactory bulb in both groups. ② The changes of mitochondrial ultrastructure in the main neurons of olfactory bulb in both groups. Results: Sixteen rats were included in the experiment and all were involved in the result analysis. ① Olfactory bulb stratification in both groups: Olfactory bulb stratification of rats in both groups showed no significant change. From the outside to the inside, they were olfactory nerve fiber layer, corolla layer, outer plexiform layer, mitral layer, Layer and olfactory tract nerve fiber layer. ② The ultrastructural changes of mitochondria in the main neurons of the olfactory bulb in the two groups: The mitochondria of the brush cells in the aged group were more, rod-shaped or oval, the mitochondrial cristae were irregular, the local arrangement was disorganized, and some of the crest ruptures disintegrated into fine particles and formed the electron High density of condensed matter, a small number of mitochondria become irregular or concentric myelin-like bodies. The mitochondria of all neurons in the young group were mostly oval, the inner and outer membranes were clearly discernible, the mitochondria cristae were arranged more evenly, and the irregular ones were occasionally seen. Conclusion: Olfactory bulb layer in aged rats is basically the same as young rats, but the ultrastructure of mitochondria in the main neurons in the olfactory bulb changes obviously, which is consistent with the decline of mitochondrial oxidative phosphorylation, which may be the result of senile olfactory dysfunction One of the main reasons.