Methods
Animals Six-week-old male ddY mice weighing 28-30 g were used in this study.
The animals were obtained from colonies of specific conventional ddY mice maintained by Japan SLC (SLC, Shizuoka, Japan).
All procedures relating to animal care and treatment conformed to the animal care guidelines of the Animal Experiment Committee of Gifu Pharmaceutical University.
All efforts were made to minimize suffering and the number of animals used.
The animals were housed at 24 ± 2°C under a 12 hr light-dark cycle (lights on from 8:00 to 20:00) and had ad libitum access to food and water.