title: The effect of environmental enrichment on substantia nigra gene expression after traumatic brain injury in rats.
abstract: Experimental investigations into the effects of traumatic brain injury (TBI) have demonstrated significant alterations in dopaminergic systems. Dopaminergic fibers originating within the substantia nigra and ventral tegmental area (VTA) are important for reward learning, addiction, movement, and behavior. However, little is known about the effect of TBI on substantia nigra and VTA function. Environmental enrichment (EE) has been shown to improve functional outcome after TBI, and a number of studies suggest that it may exert some benefits via dopaminergic signaling. To better understand the role of dopamine in chronic TBI pathophysiology and the effect of EE, we examined the mRNA expression profile within the substantia nigra and VTA at 4 weeks post-injury. Specifically, three comparisons were made: 1) TBI versus sham, 2) sham+EE versus sham+standard (STD) housing, and 3) TBI+EE versus TBI+STD. There were differential expressions of 25, 4, and 40 genes in these comparisons, respectively. Chronic alterations in genes post-injury within the substantia nigra and VTA included genes important for cellular membrane homeostasis and transcription. EE-induced gene alterations after TBI included genes important for signal transduction, in particular calcium signaling pathways, membrane homeostasis, and metabolism. Elucidation of these alterations in gene expression within the substantia nigra and VTA provides new insights into chronic changes in dopamine signaling post-TBI, and the potential role of EE in TBI rehabilitation.
authors.affiliation: Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Shin
authors.forename: James W
authors.initials: JW
authors.lastname: Bales
authors.forename: Hong Q
authors.initials: HQ
authors.lastname: Yan
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Kline
authors.forename: Amy K
authors.initials: AK
authors.lastname: Wagner
authors.forename: James
authors.initials: J
authors.lastname: Lyons-Weiler
authors.forename: C Edward
authors.initials: CE
authors.lastname: Dixon
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001930:Brain Injuries / Q000235:genetics* / Q000503:physiopathology / Q000534:rehabilitation; D020013:Calcium Signaling / Q000502:physiology; D004195:Disease Models, Animal; D004298:Dopamine / Q000096:biosynthesis / Q000235:genetics; D004777:Environment; D006799:Housing, Animal; D017403:In Situ Hybridization; D008297:Male; D009043:Motor Activity / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013378:Substantia Nigra / Q000503:physiopathology*; D059467:Transcriptome
chemical_list: D012333:RNA, Messenger; D004298:Dopamine