Abstract
Repetitive mild traumatic brain injury (mTBI) is implicated in chronic neurological illness. The development of animal models of repetitive mTBI in mice is essential for exploring mechanisms of these chronic diseases, including genetic vulnerability by using transgenic backgrounds. In this study, the rat model of impact acceleration (IA) was redesigned for the mouse cranium and used in two clinically relevant repetitive mTBI paradigms. We first determined, by using increments of weight dropped from 1 m that the 40 g weight was most representative of mTBI and was not associated with fractures, brain contusions, anoxic-ischemic injury, mortality, or significant neurological impairments. Quantitative evaluation of traumatic axonal injury (TAI) in the optic nerve/tract, cerebellum and corpus callosum confirmed that weight increase produced a graded injury. We next evaluated two novel repetitive mTBI paradigms (1 time per day or 3 times per day at days 0, 1, 3, and 7) and compared the resulting TAI, neuronal cell death, and neuroinflammation to single hit mTBI at sub-acute (7. days) and chronic time points (10. weeks) post-injury. Both single and repetitive mTBI caused TAI in the optic nerve/tract, cerebellum, corticospinal tract, lateral lemniscus and corpus callosum. Reactive microglia with phagocytic phenotypes were present at injury sites. Severity of axonal injury corresponded to impact load and frequency in the optic nerve/tract and cerebellum. Both single and repeat injury protocols were associated with retinal ganglion cell loss and optic nerve degeneration; these outcomes correlated with impact load and number/frequency. No phosphorylated tau immunoreactivity was detected in the brains of animals subjected to repetitive mTBI. Our findings establish a new model of repetitive mTBI model featured by TAI in discrete CNS tracts, especially the visual system and cerebellum. Injury in retina and optic nerve provides a sensitive measure of severity of mTBI, thus enabling further studies on mechanisms and experimental therapeutics. Our model can also be useful in exploring mechanisms of chronic neurological disease caused by repetitive mTBI in wild-type and transgenic mice.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 436-449 |
| Number of pages | 14 |
| Journal | Experimental Neurology |
| Volume | 275 |
| DOIs | |
| State | Published - Jan 1 2016 |
| Externally published | Yes |
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Keywords
- Concussion
- CTE
- Diffuse axonal injury
- Optic nerve
- Retinal ganglion cell
- Tau
- Traumatic axonal injury
ASJC Scopus subject areas
- Neurology
- Developmental Neuroscience
Cite this
Repetitive mild traumatic brain injury with impact acceleration in the mouse : Multifocal axonopathy, neuroinflammation, and neurodegeneration in the visual system. / Xu, Leyan; Nguyen, Judy V.; Lehar, Mohamed; Menon, Adarsh; Rha, Elizabeth; Arena, John; Ryu, Jiwon; Marsh-Armstrong, Nicholas; Marmarou, Christina R.; Koliatsos, Vassilis E.
In: Experimental Neurology, Vol. 275, 01.01.2016, p. 436-449.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Repetitive mild traumatic brain injury with impact acceleration in the mouse
T2 - Multifocal axonopathy, neuroinflammation, and neurodegeneration in the visual system
AU - Xu, Leyan
AU - Nguyen, Judy V.
AU - Lehar, Mohamed
AU - Menon, Adarsh
AU - Rha, Elizabeth
AU - Arena, John
AU - Ryu, Jiwon
AU - Marsh-Armstrong, Nicholas
AU - Marmarou, Christina R.
AU - Koliatsos, Vassilis E.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Repetitive mild traumatic brain injury (mTBI) is implicated in chronic neurological illness. The development of animal models of repetitive mTBI in mice is essential for exploring mechanisms of these chronic diseases, including genetic vulnerability by using transgenic backgrounds. In this study, the rat model of impact acceleration (IA) was redesigned for the mouse cranium and used in two clinically relevant repetitive mTBI paradigms. We first determined, by using increments of weight dropped from 1 m that the 40 g weight was most representative of mTBI and was not associated with fractures, brain contusions, anoxic-ischemic injury, mortality, or significant neurological impairments. Quantitative evaluation of traumatic axonal injury (TAI) in the optic nerve/tract, cerebellum and corpus callosum confirmed that weight increase produced a graded injury. We next evaluated two novel repetitive mTBI paradigms (1 time per day or 3 times per day at days 0, 1, 3, and 7) and compared the resulting TAI, neuronal cell death, and neuroinflammation to single hit mTBI at sub-acute (7. days) and chronic time points (10. weeks) post-injury. Both single and repetitive mTBI caused TAI in the optic nerve/tract, cerebellum, corticospinal tract, lateral lemniscus and corpus callosum. Reactive microglia with phagocytic phenotypes were present at injury sites. Severity of axonal injury corresponded to impact load and frequency in the optic nerve/tract and cerebellum. Both single and repeat injury protocols were associated with retinal ganglion cell loss and optic nerve degeneration; these outcomes correlated with impact load and number/frequency. No phosphorylated tau immunoreactivity was detected in the brains of animals subjected to repetitive mTBI. Our findings establish a new model of repetitive mTBI model featured by TAI in discrete CNS tracts, especially the visual system and cerebellum. Injury in retina and optic nerve provides a sensitive measure of severity of mTBI, thus enabling further studies on mechanisms and experimental therapeutics. Our model can also be useful in exploring mechanisms of chronic neurological disease caused by repetitive mTBI in wild-type and transgenic mice.
AB - Repetitive mild traumatic brain injury (mTBI) is implicated in chronic neurological illness. The development of animal models of repetitive mTBI in mice is essential for exploring mechanisms of these chronic diseases, including genetic vulnerability by using transgenic backgrounds. In this study, the rat model of impact acceleration (IA) was redesigned for the mouse cranium and used in two clinically relevant repetitive mTBI paradigms. We first determined, by using increments of weight dropped from 1 m that the 40 g weight was most representative of mTBI and was not associated with fractures, brain contusions, anoxic-ischemic injury, mortality, or significant neurological impairments. Quantitative evaluation of traumatic axonal injury (TAI) in the optic nerve/tract, cerebellum and corpus callosum confirmed that weight increase produced a graded injury. We next evaluated two novel repetitive mTBI paradigms (1 time per day or 3 times per day at days 0, 1, 3, and 7) and compared the resulting TAI, neuronal cell death, and neuroinflammation to single hit mTBI at sub-acute (7. days) and chronic time points (10. weeks) post-injury. Both single and repetitive mTBI caused TAI in the optic nerve/tract, cerebellum, corticospinal tract, lateral lemniscus and corpus callosum. Reactive microglia with phagocytic phenotypes were present at injury sites. Severity of axonal injury corresponded to impact load and frequency in the optic nerve/tract and cerebellum. Both single and repeat injury protocols were associated with retinal ganglion cell loss and optic nerve degeneration; these outcomes correlated with impact load and number/frequency. No phosphorylated tau immunoreactivity was detected in the brains of animals subjected to repetitive mTBI. Our findings establish a new model of repetitive mTBI model featured by TAI in discrete CNS tracts, especially the visual system and cerebellum. Injury in retina and optic nerve provides a sensitive measure of severity of mTBI, thus enabling further studies on mechanisms and experimental therapeutics. Our model can also be useful in exploring mechanisms of chronic neurological disease caused by repetitive mTBI in wild-type and transgenic mice.
KW - Concussion
KW - CTE
KW - Diffuse axonal injury
KW - Optic nerve
KW - Retinal ganglion cell
KW - Tau
KW - Traumatic axonal injury
UR - http://www.scopus.com/inward/record.url?scp=84949643117&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84949643117&partnerID=8YFLogxK
U2 - 10.1016/j.expneurol.2014.11.004
DO - 10.1016/j.expneurol.2014.11.004
M3 - Article
C2 - 25450468
AN - SCOPUS:84949643117
VL - 275
SP - 436
EP - 449
JO - Experimental Neurology
JF - Experimental Neurology
SN - 0014-4886
ER -