Funding for this research was provided by:
National Natural Science Foundation of China (31670419)
Received: 26 September 2018
Accepted: 23 January 2019
First Online: 13 February 2019
: All experiments were conducted in accordance with the standards of the Ethics and Animal Welfare Committee of Beijing Normal University (Approval NO. CLS-EAW-2017-014). All applicable institutional and/or national guidelines for the care and use of animals were followed.
: Not applicable.
: The authors declare that they have no competing interests.
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