Abstract:

Objective To investigate the effects of alpha-melanocyte-stimulating hormone （alpha- MSH） on the production of tumor necrosis factor-alpha （TNF-alpha） and interleukin-10 （IL-10） by peri- pheral blood mononuclear cells （PBMCs） from patients with psoriasis vulgaris. Methods Heparinized peri- pheral blood was obtained from 20 patients with psoriasis vulgaris and 10 healthy human controls. PBMCs were isolated, cultured in complete medium, and stimulated with phytohemagglutinin （PHA） alone, the combination of PHA and various concentrations of alpha-MSH, or nothing. After another 48-hour culture, ELISA and real-time PCR were performed to measure the secretion levels of TNF-alpha and IL-10 in the supernatants of cultured PBMCs as well as the mRNA expression levels of TNF-alpha and IL-10 in PBMCs. Results The secretion level of TNF-alpha in the supernatants of patient-derived PBMCs stimulated by nothing or PHA alone was significantly higher than that from normal control-derived PBMCs （329.87 ± 99.33 ng/L vs 116.95 ± 37.15 ng/L, 1756.01 ± 183.60 ng/L vs 1287.30 ± 152.36 ng/L, both P<0.01）. alpha-MSH of all tested concentrations （10-13, 10-11, 10-9, 10-7 mol/L） could inhibit the secretion of TNF-alpha by PBMCs compared with PHA alone （all P < 0.01）, and the maximum effective concentration was 10-13 mol/L. On the contrary, a significant decrease was observed in the secretion level of IL-10 in the supernatants of patient- derived PBMCs stimulated by nothing or PHA alone compared with normal control-derived PBMCs （P < 0.05 or 0.01）. Moreover, the secretion of IL-10 by PBMCs was promoted by alpha-MSH of all tested concentrations （P < 0.01 or 0.05）, with the maximum effective concentration being 10-13 mol/L （P < 0.01）. The alpha-MSH of 10-13 mol/L down-regulated the mRNA expression of TNF-alpha （P < 0.001）, but up-regulated that of IL-10 （P < 0.001） in PHA-stimulated PBMCs from patients. Conclusion alpha-MSH can regulate the production of TNF-alpha and IL-10 by PHA-stimulated PBMCs from patients with psoriasis vulgaris.