Evaluation of the human skin responses to solar-simulated radiation in an ex vivo model: effects and photoprotection.
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Presented by: Cristina Girardi
Evaluation of the human skin responses to solar-simulated radiation in an ex vivo model: effects and photoprotection.
Girardi Cristina1, Massironi Michele1, Stuhlmann Dominik2.
1 Symrise Srl, Padova, Italy
2 Symrise AG, Holzminden, Germany
Keywords: solar light, ex vivo human skin, gene array, photoprotection, L-Carnosine
Introduction:
Terrestrial solar radiation is one of the most important environmental factors affecting skin physiology. Its spectrum could be divided into three main wavelength portions: ultraviolet (UV, 5 %), visible (VIS, 50 %), and infrared (IR, 45 %). To date, it has been proven that sunlight, and more specifically the UV component, induces skin damages, both acute (e.g., sunburns, erythema, reactive oxygen species (ROS) formation) or chronic (e.g., photo-aging, immunosuppression, collagen degradation). For this reason, it is important to study the impact of solar exposure on the skin and develop new photoprotection compounds to avoid or reduce its damaging consequences.
The purpose of this work is to set up a methodology that could be used to verify the effects of solar radiation on human skin and to assess the capacity of different active principles in protecting the irradiated skin. Ex vivo human skin exposed to solar-simulated radiation was used as model to investigate oxidative stress induction, inflammatory response, and photo-aging by evaluating ROS formation, transcriptional response, and proteins level.
Methods:
This work was carried out on full-thickness human skin biopsies obtained with patients’ consent from abdominoplastic surgery. Several donors were used to set up a solar-simulated radiation model and to evaluate the efficacy of topically applied compounds in protecting the irradiated skin. Skin punch biopsies were cultured in an air-liquid interface and exposed to solar-simulated radiation and to treatments with selected compounds. In general, skin irradiation was performed daily with Atlas Suntest XLS+ (300-800 nm) at the dosage range of 50-250 J/cm2, which represents a dosage that is acquirable by few hours of sunbathing. Test compounds were applied topically before and after irradiation and renewed daily.
ROS induction was assessed by measuring the fluorescent signal in the dermis through dichlorofluoresceine diacetate method. Transcriptional analysis of the biological processes involved in solar radiation response (oxidative stress induction, inflammatory response, and photo-aging) was performed with a custom TaqMan array. Finally, the most relevant genes were validated at protein level by western blot and ELISA methods.
Results:
In our ex vivo skin model, solar-simulated radiation increases ROS production and affects the expression of several genes related to: oxidative-stress, pigmentation, immunity and inflammation, photo-aging, DNA damage/apoptosis. Among these, twelve genes were selected and validated as biomarkers to evaluate the solar radiation response of the skin and to test possible protective compounds, such as L-Carnosine.
We found that L-Carnosine mitigates the adverse effects of solar exposure reducing ROS and restoring the expression level of the most part of the selected biomarkers.
Discussion and Conclusion:
As reported in literature, in our ex vivo skin model the solar-simulated radiation induces oxidative stress and alterations of the expression of genes involved in skin functions, stress response and aging.
Our findings allowed the identification of a biomarkers panel to evaluate the effects of solar radiation on skin, and to test the capacity of applied compounds to counteract them.
Photoprotection studies showed that, L-Carnosine provides effective prevention against solar radiation induced damages reducing ROS and restoring the expression level of the most part of the selected biomarkers.
In conclusion, our solar protection model developed on ex vivo human skin proved to be a valuable system to assess the consequences of solar light and the capacity of applied compounds to counteract them.
Girardi Cristina1, Massironi Michele1, Stuhlmann Dominik2.
1 Symrise Srl, Padova, Italy
2 Symrise AG, Holzminden, Germany
Keywords: solar light, ex vivo human skin, gene array, photoprotection, L-Carnosine
Introduction:
Terrestrial solar radiation is one of the most important environmental factors affecting skin physiology. Its spectrum could be divided into three main wavelength portions: ultraviolet (UV, 5 %), visible (VIS, 50 %), and infrared (IR, 45 %). To date, it has been proven that sunlight, and more specifically the UV component, induces skin damages, both acute (e.g., sunburns, erythema, reactive oxygen species (ROS) formation) or chronic (e.g., photo-aging, immunosuppression, collagen degradation). For this reason, it is important to study the impact of solar exposure on the skin and develop new photoprotection compounds to avoid or reduce its damaging consequences.
The purpose of this work is to set up a methodology that could be used to verify the effects of solar radiation on human skin and to assess the capacity of different active principles in protecting the irradiated skin. Ex vivo human skin exposed to solar-simulated radiation was used as model to investigate oxidative stress induction, inflammatory response, and photo-aging by evaluating ROS formation, transcriptional response, and proteins level.
Methods:
This work was carried out on full-thickness human skin biopsies obtained with patients’ consent from abdominoplastic surgery. Several donors were used to set up a solar-simulated radiation model and to evaluate the efficacy of topically applied compounds in protecting the irradiated skin. Skin punch biopsies were cultured in an air-liquid interface and exposed to solar-simulated radiation and to treatments with selected compounds. In general, skin irradiation was performed daily with Atlas Suntest XLS+ (300-800 nm) at the dosage range of 50-250 J/cm2, which represents a dosage that is acquirable by few hours of sunbathing. Test compounds were applied topically before and after irradiation and renewed daily.
ROS induction was assessed by measuring the fluorescent signal in the dermis through dichlorofluoresceine diacetate method. Transcriptional analysis of the biological processes involved in solar radiation response (oxidative stress induction, inflammatory response, and photo-aging) was performed with a custom TaqMan array. Finally, the most relevant genes were validated at protein level by western blot and ELISA methods.
Results:
In our ex vivo skin model, solar-simulated radiation increases ROS production and affects the expression of several genes related to: oxidative-stress, pigmentation, immunity and inflammation, photo-aging, DNA damage/apoptosis. Among these, twelve genes were selected and validated as biomarkers to evaluate the solar radiation response of the skin and to test possible protective compounds, such as L-Carnosine.
We found that L-Carnosine mitigates the adverse effects of solar exposure reducing ROS and restoring the expression level of the most part of the selected biomarkers.
Discussion and Conclusion:
As reported in literature, in our ex vivo skin model the solar-simulated radiation induces oxidative stress and alterations of the expression of genes involved in skin functions, stress response and aging.
Our findings allowed the identification of a biomarkers panel to evaluate the effects of solar radiation on skin, and to test the capacity of applied compounds to counteract them.
Photoprotection studies showed that, L-Carnosine provides effective prevention against solar radiation induced damages reducing ROS and restoring the expression level of the most part of the selected biomarkers.
In conclusion, our solar protection model developed on ex vivo human skin proved to be a valuable system to assess the consequences of solar light and the capacity of applied compounds to counteract them.