A/J mice (8-week-old) were purchased from SLC (Shizuoka, Japan) and maintained in the Laboratory Animal Center of Tokyo Medical University for 2 weeks before use. The mice were maintained at 22 °C–24 °C and 50–60% relative humidity with a 12-h light–dark cycle. After approval by the Tokyo Medical University Animal Committee (S-23041, S-24018), all animal experiments were performed in accordance with the guidelines of the National Institute of Health.