Effects of Malassezia isolates on cytokines production associated with melanogenesis by keratinocytes / 中国医学科学院学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the co-culture of keratinocytes with Malassezia isolates which cause the pityriasis versicolor with different color and to analyze the changes of cytokines associated with melanogenesis.</p><p><b>METHODS</b>The effects of Malassezia species with different proportions on the growth rate of keratinocytes was assessed with 5 g/L methyl thiazolyl tetrazolium (MTT). Co-culture of keratinocytes and Malassezia species were performed with isolates from hyer- and hypo-pigmentation areas of pityriasis versicolor. The supernatants were collected at different time points, and the changes of basic fibroblast growth factor (b-FGF), endothelin-1 (ET-1), nerve growth factor-beta (NGF-beta), interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), stem cell factor (SCF) were recorded. Three control groups were established accordingly.</p><p><b>RESULTS</b>When the ratio between keratinocytes and Malassezia species was lower than 1 10, the growth rate of keratinocytes was not affected by Malassezia (P > 0.05). When the ratio was increased above 120, the growth rate of keratinocytes was significantly inhibited by Malassezia (P < 0.01). The secretions of IL-1alpha, IL-6, TNF-alpha, and ET-1 was significantly increased after the co-culture of keratinocytes and Malassezia (P < 0.01), while those of b-FGF, NGF-beta, and SCF had no significant changes (P > 0.05). Compared with the isolates from the hypo-pigmentation area, ET-1 induced by isolate from hyperpigmentation area significantly increased (P < 0.01).</p><p><b>CONCLUSION</b>When Malassezia isolates are co-cultured with keratinocytes, the secretions of cytokines associated with melanogenesis may differ from each other. ET-1 may play certain role in the hyper-pigmentation of pityriasis versicolor.</p>