[Study on the relationship between cadmium immunotoxicity and corticotropin-releasing factor]

To explore the relationship between cadmium immunotoxicity and corticotropin-releasing factor(CRF), murine T- and B-lymphocytes mitogen-induced proliferation function(3H-TdR incorporation method) and CRF levels of hypothalami and blood plasma were observed both in cadmium chloride(CdCl2) and CdCl2 + alpha-hCRF-treated animals in vivo. In cadmium-treated animals, T and B lymphocytes stimulation indexes were significantly lower than those in control(P < 0.05) with a dose dependent response. And interestingly, the central CRF levels in CdCl2-treated groups were significantly higher than those in control (P < 0.05), an increasing CRF level was also observed accompanied by the increase of CdCl2 level. In peripheral blood plasma, no significant difference of CRF levels was found among all groups(P > 0.05). When animals were treated with CdCl2 in combination with alpha-hCRF, no significant difference of B-lymphocyte proliferation function existed among the alpha-hCRF + CdCl2 groups (P > 0.05). Similar results were also observed in detecting T-lymphocyte proliferation function. Hypothalamic CRF levels among various doses of CdCl2 + alpha-hCRF groups showed no statistical difference, but all were higher than those in the control, and peripheral CRF levels had a trend to increase in alpha-hCRF + CdCl2 co-administrated groups. The results suggested that CdCl2 showed an immunosuppressive action upon murine T and B lymphocytes, CdCl2 could cause central CRF increase. alpha-hCRF could partially reduce the cadmium immunotoxicity. Central CRF-mediated immunomodulation was shown in cadmium immunotoxical effects on murine splenic lymphocytes.