DHEA Regulates Activation Of Mouse Spleen Lymphocytes

Objective: In order to investigate differential regulation 01 unprimed- andprimed-lyphocyte activation by DHEA, We observed the administration of DHEA tomice influenced the expression of various cytokines, e.g. IL-2, IL-4, IL-10, TGFβand costimulating cytokines(CTLA-4 B7~1 B7-2) and apoptotic protein( Bax andBcl-2).Methods: Antibody activity of mice serum was detected by indirect ELISA, andthe proliferation of lymphocyte activation was measured with MTT assay, theexpression of various cytokines, costimulators and apoptotic protein was assayed byRT-PCR.Results: Antibody level of treated group at the first week was higher than that ofcontrol group (P<0.05); Comparing to treated group and model group, Ab level inthe mice treated with DHEA at the second week was high than that treated at thefirst week and control grooup(P<0.01, P<0.01).In vitro, DHEA, arranged from 0.5 μ g/ml to 5.0 μ g/ml, no effects was found on the unprimed cells; When the concentrations of DHEA were 0.5 μ g/ml and 1.0 μ g/ml, the effects on splenocytes was minimal(p>0.05); DHEA at 5.0 μ g/ml inhibited the activation of spleen cells only when they were activated by ConA at 5.0 μ g/ml (P<0.05).DHEA downregulated the expression of IL-2 mRNA of unprimed splenocytes (P<0.01); Primed splenocytes increased the expression of IL-4 mRNA and DHEA suppressed the expression significantly(p<0.05); DHEA downregulated the expression of IL-4 mRNA of unprimed splenocytes (P<0.01); Primed splenocytesincreased the expression of IL-4 mRNA and DHEA suppressed the expression significantly(p<0.01); DHEA decreased IL-10 level of splencytes after 24 hours cultured(P<0.01) and this effect was not observed after 48 hours(P>0.05); The influence of DHEA to TGF- P gene transcription was not observed.DHEA downregulated the expression of B7-1 mRNA of unprimed splenocytes after 24 hours (P<0.05)but it upregulated the expression after 48 hours (p<0.05), so we thought DHEA regulated B7-1 mRNA expression absented time-dependent and DHEA upregulated the expression after both 24 hours and 48hours; On the contrary, DHEA suppressed the expression of B7-2 mRNA (P<0.05, P<0.01); DHEA had no effect on CTLA-4 mRNA expression of unprimed splenocytes (P>0.05), but it was in a time-dependent manner of primed splenocytes, DHEA downregulated the CTLA-4 mRNA expression after 24 hours(p<0.01) and upregulated the expression after 48 hours (p<0.01).DHEA downregulated the expression of Bax mRNA of unprimed splenocytes after 48 hours (P<0.05) but it upregulated the expression of primed splenocytes after 48 hours (p<0.05); In our study we did not observe the effect of DHEA on Bcl-2 mRNA expression (P>0.05).Conclusions: DHEA exerted a variety of positive influences on the activation stage of immunological response and less influences on the effect stage of immunological response, furthermore it suppressed the effector cell. In vitro, splenocyte proliferation was signicantly inhibited by DHEA, DHEA increased CTLA-4, B7-1 mRNA expression and decreased B7-2, IL-2 mRNA expression of splenocyte may be the mechanism of the effect, under the condition, CD28/B7 pathway weakened and CTLA-4/B7 pathway improved. DHEA downregulated the expression of Bax mRNA and no effect on Bcl-2 mRNA expression, it indicate that DHEA improve the...