The Effect Of Dahurian Angelica Root On Endothelin-induced Melanogenesis In Human Melanocytes

[Objective]It is an important defense system in human skin against harmful factors.The pivotal function epidermal melanocyte is melanin synthesis. The melaninsynthesis process is a complex pathway that is impacted by a wide range of factors.At least three enzymatic proteins in melanocytes such astyrosinase(Tyr),tyrosinase-related protein 1(Trp1) and tyrosinase -relatedprotein 2 (Trp2) are important regulating factors in metabolism of melanogenesis.ET-1 is a 2l amino acid peptide with vasoactive properties first isolated fromendothelial cells and later found to be synthesized and secreted by keratinocytesas well. The overall effect of ET-1 is the increase of melanocyte dendricity andthe enhancement of melanocyte migration and melanogenesis. Binding of ET-1 toits G protein -coupled receptor (ETBR) on melanocytes activates a cascade ofsignaling pathways,resulting in mobilization of intracellular calcium,elevation of cAMP levels, activation of PKC, and activation of mitogen-activatedprotein kinase (MAPK). Therefore, it leads to increased TYR mRNA, protein, andenzymatic activity in melanocytes as well as to an increase in melanocyte. Clinicpractice results indicated that some of Traditional Chinese Medicine possessesregulating roles on metabolism of melanocytes, but the relative mechanism wasstill not elucidated. In this study, the human epidermal melanocytes culturedin vitro was applied as specific cellular model to explore whether TraditionalChinese Medicine can modulate the expression of ETBR to effect metabolism ofmelanocytes . The aim of this study was to detect and explore the effects ofDahurian Angelica Root on endothelin-induced Melanogenesis in Human Melanocytes.[Methods]The normal human epidermal melanocytes were isolated and purified as wellas cultured in vitro. The ingredients of Traditional Chinese Medicine were extracted by alcohol. The Effect of Dahurian Angelica Root onEndothelin-induced Melanogenesis in Human Melanocytes is analyzed, includingproliferation and inhibition of tyrosinase as well as inhibition of melanogenesis.The expressions of TYR mRNA in melanocytes were detected by RT-PCR analysis. Theexpressions of ETBR were detected by immunofluorescence assay.[Results]1. The human epidermal melanocytes were successfully isolated and purified. Thecondition for primary culture of melanocyte was perfectly improved.2. The extract of Dahurian Angelica Root not only can inhibit the proliferationof human ET1-induced melanocytes and the activity of tyrosinase, but alsoinhibit the synthesis of melanin. Especially 25μg/ml extract of DahurianAngelica Root can obiviously suppress the ET1-induced proliferation of humanmelanocytes and the activity of tyrosinase.3. The result of immunofluorescence assay indicates 10nM ET1 can promote theexpression of ETBR. And 25μg/ml extract of Dahurian Angelica Root can inhibitsthe expression of ETBR which 10nM ET1 induced.[Conclusions]1.The cellular model of primary cultured melanocytes was successfully simulatedto establish.2. The extract of Dahurian Angelica Root can inhibit the proliferation ofET1-induced human melanocytes and the activity of tyrosinase.And finally resultsin reduction of melanin.3. The 25μg/ml extract of Dahurian Angelica Root can inhibit the ET1-inducedtranscription of tyrosinase gene.4. The 25μg/ml extract of Dahurian Angelica Root may inhibit the ET1-inducedexpression of ETBR.