Received: 20 December 2019
Accepted: 21 April 2020
First Online: 2 May 2020
Ethics approval and consent to participate
: The study was ratified by the Clinical Ethical Committee of Affiliated Zhongshan Hospital of Dalian University. All procedures were performed as per the ethical guidelines for the study of experimental pain in conscious animals. Great efforts were made to minimize the suffering of conscious animals.
: Not applicable.
: All authors declare that there is no conflict of interests in this study.