Ezaki Jiro, Shimada Ryo, Shibuya Misato, Kibayashi Kazuhiko
a Department of Legal Medicine , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan.
Neurol Res. 2016 Nov;38(11):994-1002. doi: 10.1080/01616412.2016.1228746. Epub 2016 Sep 10.
In experimental models of traumatic brain injury (TBI), posttraumatic hippocampal neuronal degeneration in the cornu ammonis 1 (CA1), and/or the cornu ammonis 3 (CA3) regions are regarded as the most notable phenotypic appearances relating to the pathophysiology of human post-concussion syndrome. However, these morphological changes are often also seen in subjects without TBI, namely 'sham' groups. The frequencies and reasons of appearance of hippocampal neuronal degeneration in mice with TBI and/or sham are not clear.
We compared the frequencies of hippocampal neuronal degeneration among three groups: TBI (mice with external force impact performed by Marmarou's weight drop model after scalp incision), sham (mice with scalp incision alone), and control (mice with neither external force impact nor scalp incision), using hematoxylin and eosin stain in day 6 (n = 5 in each group.) Isoflurane was used for anesthesia in all mice.
The frequencies were 80, 100, and 20% in CA1, and 20, 40, and 60% in CA3, for TBI, sham, and control, respectively. In CA1, a significant difference of the frequency was observed between sham and control (p = 0.048), but not, between TBI and sham (p = 1.000) in Fisher's exact test. In CA3, no significant difference in the frequency was observed between the three groups.
Scalp incision, rather than external impact force, might affect the CA1 hippocampal neuronal degeneration in mice with TBI. In addition, factor(s) other than external impact force or scalp incision may also cause hippocampal neuronal degeneration in both CA1 and CA3. Careful interpretation is needed concerning hippocampal neuronal degeneration induced by a weight drop device observed in mice with TBI.
在创伤性脑损伤（TBI）实验模型中，海马1角（CA1）和/或海马3角（CA3）区域的创伤后海马神经元变性被视为与人类脑震荡后综合征病理生理学相关的最显著表型表现。然而，这些形态学变化在没有TBI的受试者（即“假手术”组）中也经常出现。TBI小鼠和/或假手术小鼠中海马神经元变性出现的频率及原因尚不清楚。
我们比较了三组小鼠海马神经元变性的频率：TBI组（通过Marmarou重物坠落模型在头皮切开后施加外力冲击的小鼠）、假手术组（仅进行头皮切开的小鼠）和对照组（既无外力冲击也无头皮切开的小鼠），在第6天使用苏木精和伊红染色（每组n = 5）。所有小鼠均使用异氟烷麻醉。
TBI组、假手术组和对照组在CA1区域的频率分别为80%、100%和20%，在CA3区域分别为20%、40%和60%。在CA1区域，Fisher精确检验显示假手术组和对照组之间频率有显著差异（p = 0.048），但TBI组和假手术组之间无显著差异（p = 1.000）。在CA3区域，三组之间频率无显著差异。
对于TBI小鼠，头皮切开而非外力冲击可能影响CA1海马神经元变性。此外，除外力冲击或头皮切开外的其他因素也可能导致CA1和CA3区域的海马神经元变性。对于在TBI小鼠中观察到的由重物坠落装置诱导的海马神经元变性需要谨慎解读。
