Pycnogenol, a Standardized Extract of French Maritime Pine Bark, Inhibited the Transcriptional Expression of Th2 Cytokines by Suppressing NF-KB Activation in Primary Splenocytes of C57BL/6 Mice with Murine AIDS

摘要

LP-BM5 murine leukemia retrovirus induces the immune dysfunction by unbalanced secretion of Thl and Th2 cytokines in the murine AIDS model. In the present study, it was investigated whether pycnogenol (Pyc) administration could deactivate NF-icB to regulate the gene expression of Thl and Th2 cytokines in C57BL/6 mice with murine AIDS. Treatment with Pyc for 12 weeks significantly inhibited the loss of body weight and enlargement of spleen and lymph node usually seen with AIDS. Moreover, Pyc increasedthe plasma level of Thl cytokines, IL-2 and IFN-y, while reducing the plasma level of Th2 cytokines, IL-6, IL-10, and TNF-a. In primary culture of splenocytes, mRNA expression of Th2 cytokines was suppressed, but that of Thl cytokines was not affected.The LP-BM5 retrovirus infection stimulated the cytoplasmic activation of NF-KB and nuclear translocation of I-KB, whereas Pyc administration significantly reduced NF-KB activation and I-idB degradation. These results suggested that the inhibitory effectof Pyc on Th2 cytokines in mice with murine AIDS was dependent on suppression of the NF-icB signaling pathway and was not dependent on IFN-y level, which regulates Th2 cytokines.