Abstract: Amyloid-β (Aβ) protein and its precursor, amyloid-β precursor protein (β-APP), have traditionally been used in the diagnosis of Alzheimer disease. Their use in diagnosis of traumatic brain injury by forensic analysis is becoming more widespread. However, to date, no reliable small animal model exists to evaluate these brain injury indicators. To address this, we have studied primary brain-stem injury in rats to assess the appearance of diffuse axonal injury in brain sections and correlate these findings with appearance of Aβ and relative β-APP mRNA levels. Using an EnVision 2-step immunohistochemical staining method to measure axon diameter, we found that there was significant difference in axon diameters within the medulla oblongata and several time points after brain injury, ranging from 3 to 24 hours. In addition, mRNA expression levels of β-APP increased following brain injury, peaking 3 hours following injury and decreasing back to baseline levels by 24 hours after injury. These results suggest that using immunohistochemistry and reverse transcription–polymerase chain reaction to detect changes in Aβ-associated axonal changes and β-APP mRNA levels, respectively, can be useful for the diagnosis of diffuse axonal injury during autopsy at early time points following fatal brain injury.
From the *Department of Pathology and †Central Laboratory, Wuxi People’s Hospital, Nanjing Medical University, Wuxi, Jiangsu, People’s Republic of China.
Manuscript received October 11, 2013; accepted May 5, 2014.
Dr Sun has made substantial contributions in drafting the article and revising for important intellectual content to greatly improve the article.
This work was supported by a grant from Science and Technology Development Fund Key Project of Nanjing Medical University (Grant No. 2011NJMU207) and the other was from Wuxi Municipal Health Bureau guiding project (Grant No. MD201207).
The authors report no conflicts of interest.
Reprints: Shudong Yang, MM, Department of Pathology, Wuxi People’s Hospital, Nanjing Medical University, Qingyang Rd 299, Wuxi, Jiangsu, 214023, People’s Republic of China. E-mail: email@example.com.