| BackgroundCeramides in the skin is mainly located in the epidermis,is the main lipid in the epidermis,belonging to the sphingolipids,a class of compounds composed of fatty acids and sphingoid bases,accounting for about half of the total weight of the stratum corneum lipids.At present,12 kinds of ceramide have been found in the stratum corneum,which participate in the formation of epidermal barrier function with other lipids,and play the role of barrier,moisture,signal transduction and immune regulation in skin barrier.The change of its content may lead to impaired skin barrier function,which is closely related to the occurrence and development of some skin diseases,such as atopic dermatitis and psoriasis.The study of ceramide provides a theoretical basis and ideas for the diagnosis and treatment of clinically relevant skin diseases and the development of new drugs.Therefore,the function and mechanism of ceramide have become more and more a research focus in recent years.ObjectiveThe aim of this study was to investigate the qualitative and quantitative determination of ceramide in the skin through the non-invasive acquisition of the stratum corneum.After treatment,the ceramide in the skin of healthy Han Chinese population was detected and analyzed.The method was characteri-zed by high performance liquid chromatography tandem high resolution mass spectrometry,non-invasive detection of stratum corneum ceramide.MethodsThe experiments were performed on seven skin samples of 12 target ceramide subtypes.Since the stratum corneum is complex and diverse,all the ceramide subclasses can not be obtained.Therefore,a ceramide subclass C42H85NO3 Quantitative epidermis in the corresponding ceramide content.Application of cyanoacrylate paste cuticle stratum corneum skin samples,after a series of treatment such as lipidolysis,waiting for the machine test.The column temperature was 40°C with a Thermo Q-Exactive quadrupole-static field orbit trap high resolution FT mass spectrometer using the Ultimate3000 HPLC column,BEH C18(100×2.1 mm,1.7?m).Mobile phase A=60:40 ACN/H2O+10 mM NH4HCO2,0.1%HCO2H;B=90:10 IPA/ACN+10 mM NH4HCO2,0.1%HCO2H.Reverse the column,the flow rate of 0.3ml/min,gradient elution.Electrospray ionization(ESI)mass spectrometry was used in the mass spectrometry detection.The Full Mass ddMS2 mode was used,with a first-level resolution of 70,000 and a second-level resolution of 17,500.Data were collected and analyzed by LipidSearch software.Results In the experiment,seven kinds of skin samples were performed with 12 kinds of target neuroamide semi-quantitatively,which can be seen that Q Exactive can refer to the peak,and the response intensity is between 10~5 and 10~7.The positive ion and negative ion were collected respectively by LipidSearch software.The 12 sub-ceramides were contained in all the 7 skin samples.The ceramide C42H85NO3 standard was used to quantify the samples.The average content of the samples was 33.63,27.59,108.57,220.75,149.20,43.06,22.78?g/ml.In addition to the target lipids,positive ions identified more than 300 other lipid results,mainly ceramides and triglycerides;negative ions were identified more than 30,are ceramides.ConclusionCeramide is an important lipid in the epidermis and is closely related to the barrier function of the skin.The ceramide in the Chinese healthy population contains 12subgroups,Q Exactive ultra high resolution liquid chromatography-mass spectrometry and LipidSearch lipidomics software can be identified 12 subtypes of epidermal ceramide and other lipids,high sensitive,laid the foundation for the quantitative analysis of health or lesions and other lipid ceramide,provides a simple and rapid method.In experiments,ceramide levels vary widely among individuals.The causes of the discrepancies may be related to the unavoidable errors in the material handling,processing and testing,and may also be related to the skin barrier status. |
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