Intracerebral hemorrhage animal model

Intracerebral hemorrhage was established using the stereotaxic intrastriatal injection of collagenase type IV as described previously with certain modifications (15). Briefly, a total of 60 CD-1 mice (6–8 weeks old; 300–350 g body weight) were purchased from the Institute of Biophysics at the Chinese Academy of Sciences (Beijing, China), and housed in a temperature-controlled facility at 23±1°C with relative humidity of 50±5% and a 12 h light/dark cycle. The mice were anesthetized with 10% chloral hydrate (0.3 ml/100 g, intraperitoneally; Sigma-Aldrich; Merck KGaA, Darmstadt, Germany). The rectal temperature was maintained at 37°C throughout the surgical procedure using a heating lamp. Collagenase type IV (0.5 IU; Sigma-Aldrich; Merck KGaA) in 2 µl saline was injected into the left striatum to induce intracerebral hemorrhage over a period of 5 min. Mice were divided into two groups (the model + vehicle group and the model + simvastatin group; n=30 in each group) and intracerebral hemorrhage animals received intragastric administration of the vehicle (vehicle-treated model) or simvastatin (50 µg dissolved in 500 µl saline) once a day immediately following intracerebral hemorrhage.