The effects of PACAP on CD4+/CD8+ T cells in rats with traumatic brain injury / 中华急诊医学杂志

ABSTRACT

Objective To observe the effect of pituitary adenylate cyclase activiting polypeptide (PACAP) on traumatic brain injury (TBI) and on tbeCD4+/CD8+ T cell number in blood and spleen of rats.MethodsThe male SD rats were randomly (random number) divided into sham operation group ( n =6),normal saline + TBI group ( n =6) and PACAP + TBI group ( n =6).Right parietal cortical contusion was produced by a weight-dropping method.PACAP was administered intra-cerebroventricularly in a dose of 1 μg/5 μl 20 min before TBI.Brain tissue samples were taken 24 h after trauma.The injured brain tissue of rats was examined by HE stain.The numbers of CD4+/CD8+ T cells in blood and spleen were deteced with flow cytometry.Results Edema,hemorrhage,inflammatory cell infiltration,swollen,degenerated neurons and neurons arrayed disorderly around the injured cortex in hippocampus were found under light microscope.The average numbers of CD4 + T lymphocytes counts in blood and spleen were lower ( P =0.000,P =0.005 ),and number of CD8 + T lymphocytes was higher ( P =0.01 ) in TBI rats group than those in the sham operation group.Micro-injection of PACAP into cerebroventricular attenuated the injury,significantly increased the number of CD4 + T lymphocytes in blood and spleen ( P =0.019,P =0.839),and decreased the number of CD8 + T lymphocytes.ConclusionsPretreatment with PACAP may protect against TBI via influencing periphery T cellular immune function.