title: Delayed thalamic astrocytosis and disrupted sleep-wake patterns in a preclinical model of traumatic brain injury.
abstract: Traumatic brain injury (TBI) involves diffuse axonal injury and induces subtle but persistent changes in brain tissue and function and poses challenges for early detection of neurological injury. The present study uses an automated behavioral analysis system to assess alterations in rodent behavior in the subacute phase in a preclinical mouse model of TBI, controlled cortical impact (CCI) injury. In the first few weeks following CCI, mice demonstrated normal exploratory behaviors and other typical home-cage behaviors. However, beginning 4 weeks post-injury, CCI mice developed disruptions in sleep-wake patterns, including an increased number of awakenings from sleep. Such impaired sleep maintenance was accompanied by an increased latency to reach peak sleep in CCI mice. These sleep disruptions implicate involvement of the thalamocortical network, the activity of which must be tightly regulated to control sleep maintenance. After injury, there was an increase in reactive microglia in thalamic regions as well as delayed reactive astrocytosis that was evident in the thalamic reticular nucleus, which preceded the development of sleep disruptions. These data suggest that cortical injury may trigger inflammatory responses in deeper neuroanatomical structures, including the thalamic reticular nucleus. Such engagement of the thalamus may perturb the thalamocortical network that regulates sleep/awake patterns and contribute to sleep disruptions observed in this model as well as those documented in patients with TBI.
authors: Department of Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania; Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors: Anupam
authors: A
authors: Hazra
authors: Christine
authors: C
authors: Macolino
authors: Melanie B
authors: MB
authors: Elliott
authors: Jeannie
authors: J
authors: Chin
mesh_terms: D000818:Animals; D001930:Brain Injuries / Q000150:complications* / Q000473:pathology*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D005247:Feeding Behavior; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000209:etiology*; D006120:Grooming; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins / Q000378:metabolism; D020922:Sleep-Wake Transition Disorders / Q000209:etiology*; D013788:Thalamus / Q000473:pathology*
chemical_list: C491049:Aif1 protein, mouse; D002135:Calcium-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D008840:Microfilament Proteins
keywords: inflammation; sleep fragmentation; sleep-wake; thalamus; traumatic brain injury