title: Withdrawal from Chronic Alcohol Induces a Unique CCL2 mRNA Increase in Adolescent But Not Adult Brain--Relationship to Blood Alcohol Levels and Seizures.
abstract: BACKGROUND
  The role of neuroimmune activation in withdrawal from chronic alcohol (ethanol) has been established in both adolescent and adult models, but direct comparisons across age are sparse. Studies need to elucidate age-dependent neuroimmune effects of alcohol and to focus research attention on age-dependent mechanisms and outcomes.
  
  
  METHODS
  Adult and adolescent rats from 2 commonly used strains, Wistar and Sprague Dawley (SD), were maintained on continuous 7%, 5.35%, 4.5% alcohol diet (CAD) or cycled 7% w/v alcohol diet for 15 days. Cortical tissue was collected at 0, 8, 16, and 24 hours postwithdrawal followed by measurement of chemokine (C-C motif) ligand 2 (CCL2), tumor necrosis factor alpha, and interleukin 1 beta mRNA with quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  Both age groups and strains showed a strong cytokine mRNA response at 7% CAD. Further, a greater increase in CCL2 mRNA was observed in the cortex of adolescents at 7% CAD, which correlated with higher blood alcohol levels (BALs). Adolescents exposed to 5.35% CAD exhibited similar blood levels and cytokine responses as adults exposed to 7% CAD. Substantial variability in CCL2 mRNA responses was found only in adolescent rats exposed to 7% CAD. In this group, data could be segregated into high-responding and low-responding groups. Moreover, the data from the high-responding group were associated with seizures.
  
  
  CONCLUSIONS
  Relative to other cytokine mRNAs, CCL2 exhibits a unique response profile during withdrawal from CAD. This profile is shown in adolescents, where CCL2 is uniquely influenced by the effects of seizures. Additionally, this profile is shown by the fact that only CCL2 expression correlated with BAL that transcended age groups. These data emphasize the importance of BALs and treatment regimen on developmental neuroimmune responses and suggest that select components of the neuroimmune system are more responsive to CAD withdrawal and that neurobiological mechanisms differentiating these responses should be further explored.
authors.affiliation: Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Harper
authors.affiliation: Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Darin J
authors.initials: DJ
authors.lastname: Knapp
authors.affiliation: Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|Curriculum in Neurobiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|The UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: George R
authors.initials: GR
authors.lastname: Breese
mesh_terms: D000367:Age Factors; D000437:Alcoholism / Q000378:metabolism*; D000818:Animals; D000067401:Blood Alcohol Content; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D018932:Chemokine CCL2 / Q000096:biosynthesis*; D000431:Ethanol / Q000008:administration & dosage / Q000633:toxicity; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*
chemical_list: D000067401:Blood Alcohol Content; C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; D012333:RNA, Messenger; D000431:Ethanol
keywords: Adolescent; Adult; CCL2; Ethanol; Seizures