Gene Set Selection and Gene Expression Quantification Method Development For Anti-Aging Efficacy Evaluation of Cosmetic Product

Abstract

Skin aging is an unavoidable biological phenomenon associated with chronologically physiological change and progressive decline of skin structure. The cause of skin aging is very complex as aging can be influenced by various internal and external factors such as genetics, sun exposure, lifestyle, and dietary habits. However, UV radiation from sun exposure is the most crucial factor that can damage the skin and accelerate skin aging by ROS production. ROS can destroy the component of ECM, which is very crucial in strengthening the dermal compartment. Collagen, elastin, and hyaluronic acid are the main component of ECM, which degradation in these components can lead to many visible signs of aging, such as wrinkle, fine line, uneven skin tone, skin texture change, dry skin, elasticity loss, skin dullness, and skin thickness reduction. These changes in skin conditions on aging skin are caused by many structural losses and disorganization in the dermis layer of the aging skin, such as thinning of the dermis layer, collagen fragmentation, hyaluronic acid reduction, etc. The alteration and degradation of many key molecules in ECM is induced by the collagenase or MMPs, which degrade the collagen via MMPs and TGF-β signaling pathway. Therefore to determine the efficacy of anti-aging in repairing the aging skin, several main gene players of aging, including MMP1, COL1A1, HAS-2, HYAL-1, and ELN, were selected to be further analyzed. For a high accuracy result regarding the efficacy of skincare, gene expression assay will be conducted as the testing method. qRT-PCR was chosen as this technique is the most cost-effective, sustainable, and suitable for the size of the study with only five genes assessed. Moreover, the qRT-PCR is also considered the gold standard for the quantification of gene expression. The sample collection method preferred in this research is the non-invasive method. Hence the human skin equivalent was chosen as the skin sample as the alternative to replace the actual human skin sample.