Zheng Yiwen, Balabhadrapatruni Sangeeta, Baek Jean Ha, Chung Phoebe, Gliddon Catherine, Zhang Ming, Darlington Cynthia L, Napper Ruth, Strupp Michael, Brandt Thomas, Smith Paul F
Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School Dunedin, New Zealand.
Front Neurol. 2012 Feb 28;3:20. doi: 10.3389/fneur.2012.00020. eCollection 2012.
Previous studies in humans have shown that bilateral loss of vestibular function is associated with a significant bilateral atrophy of the hippocampus, which correlated with the patients' spatial memory deficits. More recently, patients who had recovered from unilateral vestibular neuritis have been reported to exhibit a significant atrophy of the left posterior hippocampus. Therefore, we investigated whether bilateral vestibular deafferentation (BVD) would result in a decrease in neuronal number or volume in the rat hippocampus, using stereological methods. At 16 months post-BVD, we found no significant differences in hippocampal neuronal number or volume compared to sham controls, despite the fact that these animals exhibited severe spatial memory deficits. By contrast, using bromodeoxyuridine (BrdU) as a marker of cell proliferation, we found that the number of BrdU-labeled cells significantly increased in the dentate gyrus of the hippocampus between 48 h and 1 week following BVD. Although a substantial proportion of these cells survived for up to 1 month, the survival rate was significantly lower in BVD animals when compared with that in sham animals. These results suggest a dissociation between the effects of BVD on spatial memory and hippocampal structure in rats and humans, which cannot be explained by an injury-induced increase in cell proliferation.
先前对人类的研究表明，双侧前庭功能丧失与海马体显著的双侧萎缩有关，这与患者的空间记忆缺陷相关。最近，有报道称从单侧前庭神经炎恢复的患者表现出左侧后海马体显著萎缩。因此，我们使用体视学方法研究了双侧前庭去传入（BVD）是否会导致大鼠海马体神经元数量或体积减少。在BVD后16个月，我们发现与假手术对照组相比，海马体神经元数量或体积没有显著差异，尽管这些动物表现出严重的空间记忆缺陷。相比之下，使用溴脱氧尿苷（BrdU）作为细胞增殖的标志物，我们发现在BVD后48小时至1周期间，海马齿状回中BrdU标记的细胞数量显著增加。尽管这些细胞中有很大一部分存活长达1个月，但与假手术动物相比，BVD动物的存活率显著降低。这些结果表明，BVD对大鼠和人类空间记忆和海马体结构的影响存在分离，这无法用损伤诱导的细胞增殖增加来解释。
