Heat Shock-Induced Three-Dimensional-Like Proliferation of Normal Human Fibroblasts Mediated by Pressed Silk

Fukumi Hiragami,Shigeki Inoue,Yuji Wakatake,Yoshio Kano,Hirotoshi Motoda,Chiyuki Takabayashi,Toshiaki Takezawa

doi:10.3390/ijms10114963

Abstract

The aim of this study was to determine the optimal heat treatment conditions for enhancement of pressed silk-mediated 3D-like proliferation of normal human dermal fibroblasts, as well as to determine the responses to heat shock of cells and intracellular signaling pathways. The beginning of 3D-like pattern formation of cells was observed in the second week after the start of the experiment. The mean rates of beginning of 3D-like pattern formation by cells heat-treated at 40 ºC and 43 ºC for 10 min were significantly higher (3.2- and 8.6-fold, respectively) than that of untreated cells. We found that apoptosis had occurred in 7.5% and 50.0% of the cells at one week after heat treatment for 10 min at 43 ºC and 45 ºC, respectively. Western blot analysis demonstrated that phosphorylation of p38 MAPK and that of Hsp27 were markedly increased by heat treatment at 43 ºC for 10 min. The results of an experiment using a p38 MAPK inhibitor and Hsp27 inhibitor suggest that activation of p38 MAPK by heat shock is associated with 3D-like cell proliferation and that Hsp27 contributes to the inhibition of apoptosis. The results of this study should be useful for further studies aimed at elucidation of the physiologic mechanisms underlying thermotherapy.

Highlights

Physical therapy employing electrical stimulation and ultrasound/ultraviolet or laser irradiation is widely used for wound healing of pressure sores [1,2]
We examined the effects of responses of cells to heat treatment on intracellular signaling systems of p38 mitogen-activated protein kinases (MAPKs) and Hsp27
We found that both p38 MAPK and Hsp27 were significantly activated by heat shock at

Summary

Introduction

Physical therapy employing electrical stimulation and ultrasound/ultraviolet or laser irradiation is widely used for wound healing of pressure sores [1,2]. One type of thermotherapy, is more effective for skin ulcers and pressure sores [3]. Experiments using cells subjected to various heat conditions are important for elucidating the mechanism of wound healing and for determining optimal treatment temperature and treatment time in order to maximize the positive effects of thermotherapy. Thermotherapy is different from hyperthermia used for heat treatment of a tumor This means that the determination of optimal heat conditions is important. These findings suggest that it is important to determine the optimal heat treatment condition in which thermotherapy is effective as well as to determine the optimal heat treatment for hyperthermia [4]

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