Cytokine production regulation in human astrocytes by a herbal combination (Yuldahansotang)

Yuldahansotang (YH-Tang), a Sasang Constitutional prescription composed of seven herbal mixtures, has been developed as a formula to prevent and treat cerebral infarction (CI) of Taeumins. However, the mechanisms by which this formula affects CI remain unknown. Previously, regulation of serum cytokine levels by YH-Tang has been observed in individuals at the acute stage of CI disease. It is uncertain whether this is a cause or a result of the disease process. In this study, we investigated whether YH-Tang inhibited secretion of inflammatory cytokines from human astrocytes. YH-Tang regulated the cytokine secretions in astrocytes stimulated with substance P (SP) and lipopolysaccharide (LPS). YH-Tang significantly inhibited interleukin (IL)-1, IL-4, IL-6 and tumor necrosis factor-alpha (TNF-alpha) secretion in astrocytes stimulated with SP and LPS, but did not inhibit interferon-gamma (IFN-gamma) and IL-2 secretion significantly. IL-1 has been shown to elevate TNF-alpha secretion from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. Therefore, we investigated whether IL-1 mediated inhibition of TNF-alpha secretion from astrocytes by YH-Tang. Incubation of human astrocytes with IL-1 antibody abolished the synergistic cooperative effect of LPS and SP. These results suggest that YH-Tang may indirectly inhibit TNF-alpha secretion by inhibiting IL-1 secretion. Moreover, these findings indicate that YH-Tang has regulatory effects on cytokine secretion in an acute CI patient.