title: Effects of pituitary adenylate cyclase activating polypeptide on CD4(+)/CD8(+) T cell levels after traumatic brain injury in a rat model.
abstract: BACKGROUND
  The effect of pituitary adenylate cyclase activating polypeptide (PACAP) during traumatic brain injury (TBI) and whether it can modulate secondary injury has not been reported previously. The present study evaluated the potential protective effects of ventricular infusion of PACAP in a rat model of TBI.
  
  
  METHODS
  Male Sprague Dawley rats were randomly divided into 3 treatment groups (n=6, each): sham-operated, vehicle (normal saline)+TBI, and PACAP+TBI. Normal saline or PACAP (1 μg/5 μL) was administered intracerebroventricularly 20 minutes before TBI. Right parietal cortical contusion was produced via a weight-dropping method. Brains were extracted 24 hours after trauma. Histological changes in brains were examined by HE staining. The numbers of CD4(+) and CD8(+) T cells in blood and the spleen were detected via flow cytometry.
  
  
  RESULTS
  In injured brain regions, edema, hemorrhage, inflammatory cell infiltration, and swollen and degenerated neurons were observed under a light microscope, and the neurons were disorderly arrayed in the hippocampi. Compared to the sham group, average CD4(+) CD8(-) lymphocyte counts in blood and the spleen were significantly decreased in rats that received TBI+vehicle, and CD4(-) CD8(+) were increased. In rats administered PACAP prior to TBI, damage was attenuated as evidenced by significantly increased CD4(+), and decreased CD8(+), T lymphocytes in blood and the spleen.
  
  
  CONCLUSIONS
  Pretreatment with PACAP may protect against TBI by influencing periphery T cellular immune function.
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Hua
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Mao
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Zhang
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Fu-Xing
authors.initials: FX
authors.lastname: Chen
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Zhong-Hai
authors.initials: ZH
authors.lastname: Zhou
authors.affiliation: Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China.
authors.forename: Jun-Quan
authors.initials: JQ
authors.lastname: Liu
keywords: Blood; CD4+ T lymphocyte; CD8+ T lymphocyte; Flow cytometry; Pituitary adenylate cyclase activating polypeptide; Rat; Spleen; Traumatic brain injury