1. Ultramicropathology Experimental Center, Pathology College, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
2. Department of Basic Medicine, School of Nursing and Rehabilitation, Xinyu University, Xinyu, Jiangxi 338004, P.R. China
3. Pathogenic Biology and Immunology Experimental Teaching Center, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
4. Department of Anatomy, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
5. Department of Pathology, The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang 150040, P.R. China