Effects Of E On Immune Functions Of Al-Exposed Splenic Lymphocyte Of Rats Cultured In Vitro

To investigate the immune mechanisms of epinephrine （E） on cultured splenic lymphocytesexposed to aluminum （Al） in rats. The lymphocytes were isolated from the spleen of Wistar ratsand cultured in RPMI-1640medium and exposed to0.6059mmol/L AlCl₃·6H₂O （Al-exposedgroup, CG）,0.6059mmol/L AlCl₃·6H₂O+1×10^-7mol/L E （low-dose group, LG）,0.6059mmol/LAlCl₃·6H₂O+1×10^-6mol/L E （medial-dose group, MG） and0.6059mmol/L AlCl₃·6H₂O+1×10-5mol/L E （high-dose group, HG） in incubators containing5%CO2at37°C for24h, and the controlgroup （BG） was added the same volume of RPMI-1640medium. Lymphocyte proliferation, Tlymphocyte subsets, the contents of IL-2, TNF-α, immunoglobulin G （IgG） and intracellular cAMP,β2-adrenergic receptor（β2-AR） density and the expression of β2-AR mRNA were determined byCCK-8assay, flow cytometry, radioimmunoassay, enzyme-linked immunosorbent assay （ELISA）,reverse transcription-polymerase chain reaction （RT-PCR） method on cultured spleen lymphocytesof rats in vitro.The results were showed as follows:1. T lymphocyte proliferation was lower in all E groups than that in CG （P<0.05, P<0.01）. Blymphocyte proliferation was higher than that in CG, and there were significantly differences inMG and HG compared with CG （P<0.05, P<0.01）. Both T and B lymphocyte proliferations werelower in CG than that in BG （P<0.01）. The results indicated that E inhibited T lymphocyteproliferation and promoted B lymphocyte proliferation exposed to Al.2. The positive rates of CD3⁺, CD4⁺, CD8⁺T lymphocytes, and the ratio of CD4⁺/CD8⁺Tlymphocytes were lower in all E groups than those in CG, there were dose-dependent manner,whereas the positive rates of CD3⁺in MG and HG, CD4⁺in all E groups, CD8⁺and the ratio ofCD4⁺/CD8⁺in HG were lower than those in CG （P<0.05, P<0.01）. The positive rates of CD3+,CD4⁺, CD8⁺T lymphocytes were lower in CG compared with BG （P<0.05, P<0.01）. The resultsindicated that E aggravated the immune function inhibition of Al-exposed T lymphocytes.3. The contents of IL-2, and TNF-α were lower in all E groups than those in CG, there wereNE-dose-dependent manner, and in MG and HG had significant differences compared with CG（P<0.05, P<0.01）, and in CG were lower compared with BG（P<0.01）. The results indicated that Ecan inhibit cytokines secretion of lymphocytes exposed to Al.4. The contents of IgG were higher in all E groups than that in CG, and that in MG and HGwere significantly higher compared with CG, and in CG had significant differences compared withBG （P<0.05）. The results indicated that E can disorder the immunoglobulin secretion of lymphocytes exposed to Al.5. The β2-AR density, β2-AR mRNA expression and cAMP contents were increased graduallyin all E groups, there were NE-dose-dependent manner. The β2-AR density, β2-AR mRNAexpression in MG and HG, and the cAMP contents in all E groups were higher than those in CG（P<0.01, P<0.05）, and they were higher in CG compared with BG （P<0.01）. The results indicatedthat E aggravated immunotoxicity of lymphocytes exposed to Al through β2-AR-cAMP pathways.