他克莫司对角质形成细胞生长的抑制作用及其机制

为观察他克莫司对角质形成细胞表面表达趋化因子受体CXCR2的影响，探讨其在治疗银屑病中的作用机制，在不同时间段内用不同浓度的他克莫司处理人类角质形成细胞株HACAT，通过MTT法检测了他克莫司抑制HACAT增殖的有效剂量及时间；通过流式细胞术（FACS0分析他克莫司处理的HACAT表达CXCR2的情况。结果显示，HACAT经他克莫司在39ng/ml-5000ng/mL浓度范围内处理24h后的OD值较未处理组降低，但不具有统计学意义（P＞0．05）；经他克莫司处理48h的细胞OD值较未处理组明显降低（P＜0．05），各浓度之间无显著差异（P＞0．05）；HACAT在39ng/mL他克莫司处理48h后CXCR2的表达明显低于正常对照组。结果说明，他克莫司治疗银屑病的作用机制部分是通过抑制角质形成细胞表达CXCR2，从而达到抑制角质形成细胞增殖的目的。

The inhibitory effect of tacrolimus on the growth of keratinocyte and its mechanisms

This study is to investigate the effect of tacrolimus on the CXCR2 expression in keratinocytes so as to analyse the mechanisms of tacrolimus in the treatment of psoriasis. After the keratinocyte cell line HACAT was cultured with tacrolimus, the proliferative capacity of the cells was detected by MTT method. The expression of CXCR2 in HACAT cells treated with tacrolimus was assayed by flow cytometry. The tacrolimus at concentrations between 39 ng/mL and 5000ng/mL could inhibite the growth of human keratinocyte and the obvious decrease was detected after 24h treatment (P< 0.05). But no significant difference was observed between the various concentrations. At the same time, the expression of CXCR2 in the cells was also down regulated. One of the mechanisms for tacrolimus in treatment of psoriasis might be to down-regulate the CXCR2 expression in keratinocytes, which contributes to the inhibition of the over proliferation of keratinocytes in psoriasis.