Tensile Stress Regulation of NGF and NT3 in Human Dermal Fibroblast

摘要

Fibroblast is a major type of mechanosensitive cells in connective tissues, which transfers mechanical signals to intercellular biochemical events. Numerous previous studies have shown that the tensile stress alters ECM-related gene expression in fibroblast. The aim of this study is to investigate the effects of tensile stress on the neurotrophin expression of dermal fibroblast in vitro. Human dermal skin fibroblast cells synthesize and release neurotrophins such as nerve growth factor (NGF) and neutrophin-3 (NT3). NGF and NT3, members of NT (neurotrophin) family, stimulates fibroblast migration and are related to wound healing. Also, it is known that upregulation of NGF takes part in maintaining the biome-chanical properties of the dermis. In this study, seeded cells on the polydimethylsiloxane(PDMS) substrate using a tensile stimulation device. At the uniaxial stretch of 10% strain and frequency of 0.5 Hz, different resting times of 0 min, 20 min, and 60 min were placed in between 10 min stimulations periods for the total stimulation of 1 hr and 2 hr. Results have shown that NGF mRNA levels had increased after 1 hr of stimulation, and more NGF mRNA was transcribed up to two-folds as the resting time increased. However, the level of mRNA transcription had decreased upon additional stimulation. On the other hand, NT3 mRNA levels had decreased by 50% in all applications. This result demonstrates that the tensile stress may regulate the expression of NGF and NT3, which could be a key factor for the neurocosmetic applications. We also investigated the effects of frequency and the magni- tude of strain on the gene expression.