supported by the National Natural Science Foundation of China(No.81202031);Scientific Program of Health and Family Planning Commission of Jilin Province;China(No.2014Z103);Scientific Program of Education Department of Jilin Province;China(No.2013-351);Project of Undergraduate Innovation and Entrepreneurship of Jilin Province;China(2013;2014);Undergraduate Science Foundation of Jilin Medical College;China(No.2012-12)