Development of a novel ex vivo organ culture system to improve preservation methods of regenerative tissues.

Recent advances in regenerative technology have made the regeneration of various organs using pluripotent stem cells possible. However, a simpler screening method for evaluating regenerated organs is required to apply this technology to clinical regenerative medicine in the future. We have developed a simple evaluation method using a mouse tooth germ culture model of organs formed by epithelial-mesenchymal interactions. In this study, we successfully established a simple method that controls tissue development in a temperature-dependent manner using a mouse tooth germ ex vivo culture model. We observed that the development of the cultured tooth germ could be delayed by low-temperature culture and resumed by the subsequent culture at 37 °C. Furthermore, the optimal temperature for the long-term preservation of tooth germ was 25 °C, a subnormothermic temperature that maintains the expression of stem cell markers. We also found that subnormothermic temperature induces the expression of cold shock proteins, such as cold-inducible RNA-binding protein, RNA-binding motif protein 3, and serine and arginine rich splicing factor 5. This study provides a simple screening method to help establish the development of regenerative tissue technology using a tooth organ culture model. Our findings may be potentially useful for making advances in the field of regenerative medicine.