1. Department of Histology, Embryology and Neurobiology, West China School of Basic Medical Sciences, Sichuan University, Chengdu 610041, Sichuan Province, China
2. Department of Anatomy, Histology and Embryology, Development and Regeneration Key Lab of Sichuan Province, Chengdu Medical College, Chengdu 610500, Sichuan Province, China
3. Laboratory of Basic Medical Sciences, West China School of Basic Medical Sciences, Sichuan University, Chengdu 610041, Sichuan Province, China