2.3 Drug administration
PCP, generously gifted by professors Haohong Li and Xiaohui Wang from the Changchun Institute of Applied Chemistry, Chinese Academy of Science. Fingolimod (Sigma-Aldrich, St. Louis, MO, USA, Cat# SML0700), was dissolved in normal saline (NS) and freshly prepared daily. The dose regimen was based on an established protocol (Marquis, Audet, Doré, & Goulet, 2007). The animals received a daily intraperitoneal (i.p.) injection of normal saline or PCP (10 mg/kg) for 14 days. After a seven-day wash-out period, the PCP-exposed rats received 0.5 mg/kg or 1 mg/kg fingolimod as the treatment group or NS as the PCP model group. Behavioural testing began at the end of the drug treatment (Figure 1). To label proliferating cells, the rats received an i.p. injection of 50 mg/kg BrdU (Sigma-Aldrich, St. Louis, MO, USA, Cat# B5002) at the end of the Morris water maze test, and brain tissue was collected 24 h later.