1. School of Life Science, Northeast Agricultural University, Harbin, Heilongjiang�150030, P.R.�China
2. Key Laboratory of Neurosurgery, College of Heilongjiang Province; The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang�150001, P.R. China
3. School of Life Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, P.R. China
4. College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P.R.�China
5. Key Laboratory of Neurosurgery, College of Heilongjiang Province; The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China