Animals
Male ApoE-/- C57BL/6 mice (8-weeks-old) were purchased from Vital River Inc. (Beijing, China). All interventions and animal care methods were conducted according to the Guidelines and Policies for Animal Surgery offered by the Animal Ethics Committee of the Second Affiliated Hospital of Harbin Medical University (Harbin, China). The mice were kept in a temperature-controlled facility (temperature: 24 degrees Celsius to 25 degrees Celsius, humidity: 55%) with a 12 h light/12 h dark photoperiod, and food and water were freely available.
ApoE-/- mice were randomized into two groups and treated as follows: control (saline, ip.) and ATO (2.5 mg kg-1 d-1, ip.). Mice were maintained on a Western diet for four months, consisting of 78.85% of basic mice maintain feed, 21% of fat and 0.15% of cholesterol. At the last month, mice were fed with intraperitoneal administration of the drugs once every two days for one month, a total of 15 times. All of the animals were killed at the end of the testing period. Blood was collected from the retro-orbital vein and serum was separated.  Blood urea acid (UA) and creatine Kinase(CK) levels as well as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were determined on a Hitachi 917 Roche Analyzer (Meylan, France) using dedicated reagents. The investigator was blinded to the group allocation and assessing the outcome during the experiments.