The Suppression Effects Of Benzopyrene On T Lymphocytes In Mice And The Regulation On Related Signal Transduction Pathways

Benzopyrene, which is widely presented in smoked and grilled food, is apolycyclic aromatic hydrocarbon contaminants. It has carcinogenic, mutagenic andother toxic effects, which are latent and accumulation. This study shows the effects ofbenzopyrene on BALB/c mice T lymphocytes and the regulation of signaltransduction pathways under non-cytotoxic dose. Besides, the study also provides theexperimental basis for elucidating the mechanism on immunotoxicity of benzopyreneand finding out more sensitive and effective toxicity biomarker which is easy to bedetected.This research mainly focused on the immunosuppressive effects of benzopyreneon BALB/c mice T lymphocytes in vitro: Firstly, the mouse spleen T lymphocyte wasseparated and cultured. Afterwards, the non-cytotoxic dose range of benzopyrene wasinvestigated by MTT assay. Then we investigated the effects of benzopyrene onconcanavalin (ConA)-induced proliferation of T cells, and screen out three dosegroups as low, medium and high dose group（0.1μg/mL、0.2μg/mL、0.4μg/mL）,respectively. Secondly, we monitored the impacts of benzopyrene on cytokines (IL-2,IFN-γ, IL-4) using ELISA assay, which were secreted by ConA-induced T cells.Thirdly, we studied the influence of benzopyrene on intracellular Ca2+by detectingthe concentration of intracellular [Ca2+] i and the protein expression of CaM. Lastly,the impact of benzopyrene on the signaling pathways of NFAT and NF-κB weredetected by Western Blotting, which were secreted by ConA-induced T cells.The results obtained from in vitro studies showed that the non-cytotoxic doserange of benzopyrene was0-0.4μg/mL.0.1μg/mL,0.2μg/mL and0.4μg/mL waschosen as low, medium and high dose group, respectively. Moreover, the resultsconfirmed that benzopyrene could inhibit ConA-induced proliferation of Tlymphocytes and the IL-2, IFN-γ and IL-4cytokines. Besides, benzopyrene also hadthe inhibition on [Ca2+]i in T lymphocyte, the expression of CaM protein and thepathways of NFAT and NF-κB in T cells. Notably, all of the inhibitions mentionedabove were dose-dependent. The results obtained from in vito studies showed that benzopyrene could inhibit the mouse T lymphocytes and participated in the regulationof NFAT and NF-κB pathway.In summary, benzopyrene, at non-cytotoxic dose, has immunosuppressive effecton BALB/c mice T lymphocytes in a dose dependent manner. Theimmunosuppressive effect may be through NFAT, NF-κB pathway. This study wasbenefit to find biological-toxicity markers, which are indicators of early damages, andare easily detected. Thus, this work will lay foundations for setting up new safetylimit of benzopyrene.