Animals
Female BLAB/c mice were purchased from Nanjing Medical University and were bred in Nanjing Drum Tower Hospital. All mice were nurtured in ventilated cages and had free access to water and food. The protocols were approved by the Animal Care and Use Committee of Nanjing Medical University and animals were treated following the National Institutes of Health Guide for the Care and Use of Laboratory Animals. All operations were carried out in accordance with the approved procedures.