Animals
Female C57BL/6 mice aged 6-8 weeks and weighing 18-20g were purchased from Vital River Laboratory Animal Technology Co., Ltd.(Beijing, China) and bred in our animal facility at The First Hospital of Jilin University. The mice were housed in pathogen-free conditions and had free access to food and water. All experiments were performed in accordance with the local ethics committee of The First Hospital of Jilin University, Changchun of China(Ethical approval number: 2017-216).