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 (1g/5L) 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. CONCLUSION: Pretreatment with PACAP may protect against TBI by influencing periphery T cellular immune function.
ABSTRACT
The aim of this study was to investigate the inhibitory effect of Toll-like receptor 7 (TLR7) agonist gardiquimod on K562 cells. Human γδT cells from peripheral blood cells were amplified by isopentenyl pyrophosphate. The proliferation capacity of γδT cells and K562 cells were measured with MTT assay after treatment with different concentrations of gardiquimod. Cytotoxicity of γδT cells on K562 cells was detected by CCK-8 kit, and the intracellular expression of TLR7, cell cycle and apoptosis of K562 cells before and after treatment with gardiquimod were measured by flow cytometry. The results demonstrated that gardiquimod could significantly stimulate the proliferation of γδT cells, and inhibit proliferation of K562 cells under the concentration of 11.0 µg/ml for 48 h. The expression of TLR7 increased after treatment with gardiquimod. No apoptosis was observed, but there were significant changes in cell cycle, moreover the K562 cells treated with gardiquimod were more killed by γδT cells. It is concluded that the gardiquimod can inhibit the proliferation of K562 cells and enhance their sensitivity to killing activity of human γδT cells.