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Long-term dysfunction following diffuse traumatic brain injury in the immature rat
P D Adelson1, C E Dixon, P M Kochanek
1Department of Pediatric Neurosurgery, Children's Hospital of Pittsburgh, Pennsylvania 15213-2583, USA. adelsod@chplink.chp.edu
Insights
Severe diffuse traumatic brain injury (TBI) in young rats causes lasting motor and cognitive deficits, impacting weight gain. This TBI model aids in testing new therapies for immature brain injury outcomes.
Area of Science:
- Neuroscience
- Developmental Biology
- Traumatology
Background:
- Children with severe diffuse traumatic brain injury (TBI) often experience long-term cognitive impairments.
- Understanding TBI effects on the immature brain is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the long-term functional outcomes and developmental effects of diffuse impact (DI) acceleration TBI in immature rats.
- To establish a TBI model in young rats for evaluating therapeutic interventions.
Main Methods:
- Immature rats (postnatal day 17) underwent DI TBI or sham procedures.
- Vestibulomotor function was assessed using beam balance and inclined plane tests for 10 days.
- Cognitive function was evaluated using the Morris water maze (MWM) monthly for 3 months.
- Body and brain weights were measured post-injury.
Main Results:
- DI rats showed persistent motor deficits for 10 days post-injury.
- Significant long-term cognitive deficits were observed in the MWM up to 90 days post-injury.
- Injured rats exhibited reduced body and brain weight gain compared to sham controls at 3 months.
Conclusions:
- Diffuse TBI in immature rats results in reversible motor deficits and sustained cognitive impairments.
- The injury model demonstrates significant effects on growth and development up to 3 months post-trauma.
- This model is valuable for preclinical testing of therapies targeting long-term outcomes in pediatric TBI.
Abstract:
Children often suffer sustained cognitive dysfunction after severe diffuse traumatic brain injury (TBI). To study the effects of diffuse injury in the immature brain, we developed a model of severe diffuse impact (DI) acceleration TBI in immature rats and previously described the early motor and cognitive dysfunction posttrauma. In the present study, we investigated the long-term functional ability after DI (150 gm/2 m) compared to sham in the immature (PND 17) rat. Beam balance and inclined plane latencies were measured daily for 10 days after injury to assess gross vestibulomotor function. The Morris water maze (MWM) paradigm was evaluated monthly up to 3 months after DI and sham injuries. Reduced latencies on the balance beam and inclined plane were observed in DI rats (p < 0.05 vs. sham [n = 10 per group]) at 24 h and persisted for 10 days postinjury. DI produced sustained MWM performance deficits (p < 0.05 vs. sham) as indicated by the greater latencies to find the hidden platform remarkably through 90 days after injury. Lastly, the brain and body weights of the injured animals were less than sham (p < 0.05) after 3 months. We conclude that a diffuse TBI in the immature rat: (a) created a consistent, marked, but reversible motor deficit up to 10 days following injury; (b) produced a long-term, sustained performance deficit in the MWM up to 3 months posttrauma; and (c) affected body and brain weight gain in the developing rat through 3 months after injury. This TBI model should be useful for the testing of novel therapies and their effect on long-term outcome and development in the immature rat.