Effects Of Hypoxia On Proliferation And Activation Of Lymphocyte And Secretion Of Proinflammatory Cytokines In Macrophages And The Mechanisms

Aim:To investigate the relation between the change of lymphocyte [Ca2+]i and immune function of lymphocytes and the active process of NF-icB signal transduction pathway in MΦ which mediates the expressions of proinflamma-tory cytokines TNF-α and IL-6 during hypoxia so as to understand the effects of hypoxia on the functions of immune cells and the mechanisms. Methods:The hypoxic cultured models of lymphocytes and MΦ were Made. The levels of IL-^ TNF-a and IL-6 in the medium were determined by ELISA method. The lymphocyte transformation rate was measured by MTT method. The mRNA expressions of TNF-α IL-6 and p65 were observed by RT-PCR method. The level of ROS in M(|) and the change of lymphocyte [Ca2+] i were assayed by fluorescence spectrophotometry method. IkBα phosphorylation and NF-KB activation were detected by Western blotting method. Results: (1) Lymphocyte [Ca2+]i was decreased during acute hypoxia, at the same time , the secretions of IgG and IL-2 and lymphocyte proliferation were also decreased. After hypoxic precondition they all had no significant changes compared with control respectively. (2)During hypoxia the expressions of TNF-a and IL-6 were increased in MΦ and IkBα phosphorylation, NF-KB activation and expression of P65 mRNA were also upregulated. (3) Antioxidant NAC could block IicBa phosphorylation caused by hypoxia in MΦ. Protein tyrosine kinase inhibitor genistein could lower NF-KB activation caused by hypoxia. Conclusions: ?The immune function of lymphocyte was decreased During acute hypoxia and after hypoxic precondition was improved, in which Ca2+ played an importantrole. ㏕he level of ROS was increased in M During hypoxia. ROS might activate protein tyrosine kinase and induced IkBα phosphorylation and NF~KB activation, which could enhance the secretions of proinflammatory cytokines TNF-α and IL-6.