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Heat‐shock‐induced three‐dimensional‐like proliferation of mouse fibroblasts mediated by hydroxyapatite
Author(s) -
Hiragami Fukumi,
Akiyama Junichi,
Koike Yoshihisa,
Kano Yoshio
Publication year - 2007
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1042/ba20060200
Subject(s) - p38 mitogen activated protein kinases , cell growth , western blot , phosphorylation , microbiology and biotechnology , heat shock , heat shock protein , apoptosis , mapk/erk pathway , andrology , mitogen activated protein kinase , chemistry , biology , biochemistry , medicine , gene
The aim of the present study was to determine both the minimal and the optimal conditions under which heat treatment is effective for enhancing 3D (three‐dimensional)‐like cell proliferation. C3H10T1/2 mouse fibroblasts were cultured with hydroxyapatite granules for 10 weeks after heat treatment at 40, 41.5, 43, 44 or 45°C for 2, 10, 15, 20, 30, 45, 60, 90, 180 and 360 min. Then minimal and optimal conditions of temperature and duration of heat treatment for induction of 3D‐like proliferation of cells were determined. The minimal conditions of heat treatment to induce 3D‐like proliferation were 43°C for 2 min and the optimal conditions were 43°C for 10 min. The mean rates of formation of 3D‐like proliferation patterns by cells heat‐treated at 43°C for 2 and 10 min were significantly higher (1.7‐ and 3.7‐fold respectively) than that by untreated cells ( P <0.05). We also observed significantly greater effects of heat treatment on 3D‐like proliferation at 40°C for 90 or 180 min and at 41.5°C for 15 min and 44°C for 10 min. We found that apoptosis had occurred in 7.5 and 87.0% of the cells at 1 week after heat treatment at 43°C for 10 min and 30 min respectively. Western‐blot analysis demonstrated that phosphorylation of p38 MAPK (mitogen‐activated protein kinase) was markedly increased by heat treatment at 43°C for 10 min. These findings suggest that activation of p38 MAPK by heat shock is associated with 3D‐like cell proliferation. The results of the present study should be useful for further studies aimed at elucidation of the physiological mechanisms underlying thermotherapy and hyperthermia.