分泌性的糖蛋白Wnt5a对永生化小鼠黑素细胞系melan-a细胞产黑素的影响

Effect of the Secretory Glycoprotein Wnt5a on the Melanogenesis of the Immortalized Mice Melanocyte Lineage Melan-a Cells

目的:探讨分泌性的糖蛋白Wnt5a对永生化小鼠黑素细胞系melan-a细胞产黑素的影响。方法:用带有Wnt5a基因的腺病毒及对照组腺病毒作为载体感染体外培养的melan-a黑素细胞;MTT法测定细胞增殖率;体外氧化DOPA反应法测定酪氨酸酶活性;NaOH法测定黑素含量;RT-PCR方法检测melan-a细胞中MITF的表达。结果:与AdGFP对照组相比,AdWnt5a处理组melan-a细胞的增殖率明显降低(P<0.01);DOPA反应法和NaOH法检测结果发现,Wnt5a能显著降低melan-a细胞内酪氨酸酶活性(P<0.01)以及黑素含量(P<0.05);RT-PCR结果表明,Wnt5a显著下调melan-a细胞内MITF的表达(P<0.01)。结论:以上结果显示,AdWnt5a处理组melan-a细胞的增殖率、酪氨酸酶活性、产黑素的量及MITF的表达均有所下降。实验结果提示,Wnt5a能有效抑制melan-a细胞产黑素的能力,并且其作用机制可能与下调MITF的表达有关。

Objective： To investigate the effect of Wnt5a on the Melanogenesis of Melan-a cells. Methods： Cultured melan-a melanocytes in vitro were infected by the adenovirus with Wnt5a gene; MTT method was used for determination of cell proliferation rate; Tyrosinase activity assays were performed by the method of DOPA; NaOH method was used for determination of melanin content; The expression of MITF in melan-a melanocytes was performed by reverse transcription-polymerase chain reaction （RT-PCR）. Results： Compared with AdGFP, the proliferation rate of AdWnt5a-infected melan-a cells reduced significantly （P〈0.01）. DOPA and NaOH assay revealed that Wnt5a significantly inhibited the activity of tyrosianse （P〈0.01） and melanin content （P〈0.05） in melan-a cells. Furthermore, RT-PCR analysis showed that Wnt5a downregulated the expression of MITF in melan-a cells （P〈0.01）. Conclusion： Collectively, it is demonstrated that Wnt5a inhibited the proliferation, downregulated the activity of tyrosinase, the melanin content and the expression level of MITF in melan-a cells. The results suggested that Wnt5a contributed to inhibit the melanin synthesis through downgulating the expression of MITF in melan-a cells.