Effects Of Dfp On Immune Functions Of Al-Exposed Splenic Lymphocytes Of Rats Cultured In Vitro

To investigate the effects of1,2-dimethyl-3-hydroxy-4-pyridone (DFP) on immune functions of Aluminum (Al)-exposed splenic T and B lymphocytes of rats cultured in vitro, the lymphocytes were isolated from the spleen of healthy Wistar rats weighed110-120g and cultured in RPMI-1640medium and exposed to0.0945mg/mL AlC13(Al-exposed group, AG),0.0945mg/mL AlC13+0.189mg/mL DFP (low-dose group, LG),0.0945mg/mL AlC13+0.284mg/mL (medial-dose group, MG) and0.0945mg/mL AlC13+0.378mg/mL DFP (high-dose group, HG) in incubators containing5%CO2at37℃for24h, and the control group (CG) was added the same volume of RPMI-1640medium. The effects of DFP on proliferation, cytoactive, T lymphocyte subsets, cytokines, antioxidant system and apoptosis of Al-exposed splenic lymphocytes of rats were determined by MTT assay, dinitrophenylhydrazine development process, radioimmunoassay, nitrale reduetase, colorimetric method, NO metabolism, thio barbituric acid assay, xanthine oxidase method, ammonium molybdate development process and flow cytometry.The results showed as follows:1The proliferations of T and B lymphocytes were reduced by A1exposure, and the proliferations in LG, MG and HG were higher than those in AG. The proliferation in MG was significantly higher than that in AG (P<0.01). It indicated that the proliferations of Al-exposed T and B lymphocytes were regained by DFP.2The leakage rate of lactic dehydrogenase (LDH) in AG was higher than that in CG (P<0.01). DFP could obviously reduce the leakage rate of LDH in Al-exposed groups, and the leakage rate of LDH in MG was significantly lower than that in AG (P<0.01). It indicated that cytomembrane was recovered by DFP in Al-exposed lymphocytes.3The levels of interleukin (IL)-2, interleukin (IL)-6and tumor necrosis factor (TNF)-a were lower in AG than those in CG (P<0.01), the levels of these cytokines in LG, MG and HG were all higher than those in AG (P<0.05; P<0.01). It indicated that secretion of cytokines was recovered by DFP in A1-exposed lymphocytes.4The positive rates of CD3+and CD4+T lymphocytes, and the ratio of CD4+/CD8+T lymphocytes in LG, MG and HG were higher than those in AG, whereas the positive rate of CD8+T lymphocytes in LG, MG and HG was lower than that in AG. And there were significant differences between MG and AG (P<0.01). It indicated that the functions of Al-exposed T lymphocytes subsets were recovered by DFP.5The activity of nitric oxide synthase (NOS), the levels of nitric oxide (NO) and malonaldehyde (MDA) in LG, MG and HG were lower than those in AG. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were higher in LG, MG and HG than those in AG. And there were significant differences between MG and AG (P<0.01). It indicated that DFP could relieve the A1-induced lymphocytes oxidativestress, which would restrain the A1toxicity.6The early apoptosis index and total apoptosis index were both lower in MG than in AG (P <0.01). It indicated that the lymphocytes apoptosis could be remitted by DFP in dose of MG.