Clin Exp Emerg Med.  2019 Jun;6(2):125-137. 10.15441/ceem.18.019.

Exploratory, cognitive, and depressive-like behaviors in adult and pediatric mice exposed to controlled cortical impact

• Lee SW
• Jang MS
• Jeong SH
• Kim H

• KMID: 2452985
• DOI: http://doi.org/10.15441/ceem.18.019

Abstract

OBJECTIVE
Sequelae of behavioral impairments associated with human traumatic brain injury (TBI) include neurobehavioral problems. We compared exploratory, cognitive, and depressive-like behaviors in pediatric and adult male mice exposed to controlled cortical impact (CCI).
METHODS
Pediatric (21 to 25 days old) and adult (8 to 12 weeks old) male C57Bl/6 mice underwent CCI at a 2-mm depth of deflection. Hematoxylin and eosin staining was performed 3 to 7 days after recovery from CCI, and injury volume was analyzed using ImageJ. Neurobehavioral characterization after CCI was performed using the Barnes maze test (BMT), passive avoidance test, open-field test, light/dark test, tail suspension test, and rotarod test. Acutely and subacutely (3 and 7 days after CCI, respectively), CCI mice showed graded injury compared to sham mice for all analyzed deflection depths.
RESULTS
Time-dependent differences in injury volume were noted between 3 and 7 days following 2-mm TBI in adult mice. In the BMT, 2-mm TBI adults showed spatial memory deficits compared to sham adults (P < 0.05). However, no difference in spatial learning and memory was found between sham and 2-mm CCI groups among pediatric mice. The open-field test, light/dark test, and tail suspension test did not reveal differences in anxiety-like behaviors in both age groups.
CONCLUSION
Our findings revealed a graded injury response in both age groups. The BMT was an efficient cognitive test for assessing spatial/non-spatial learning following CCI in adult mice; however, spatial learning impairments in pediatric mice could not be assessed.

Keyword

Brain injuries, traumatic; Controlled cortical impact; Age difference; Neurobehavioral differences

MeSH Terms

Adult*
Animals
Brain Injuries
Eosine Yellowish-(YS)
Hematoxylin
Hindlimb Suspension
Humans
Learning
Male
Memory
Mice*
Rotarod Performance Test
Spatial Learning
Spatial Memory
Eosine Yellowish-(YS)
Hematoxylin