Abstract: Objective The suture methods for the establishment of rat model of focal cerebral ischemia/reperfusion is used widely,but problems such as model unstability,low achievement ratio always exist.The Objective of this study is to improve the methods for getting successful of middle cerebral artery occlusion(MCAO) model.Methods Some newer methods were employed to overcome some drawbacks in traditional methods: 1) continuous laser doppler fluid meter was employed to monitor local cerebral blood flow;2) which was reduced to 15% of baseline; 3) the opposite common carotid artery was clamped;4) silicone rubber coated monofilament was selected to reduce the risk of vessel injury and intracranial bleeding.Results As soon as the filament got into the suitable position,the local cerebral blood flow would decreased sharply to 30% or less of baseline,but rarely to 15% of baseline.When the opposite common carotid artery was clamped simultaneously,the local cerebral blood flow would reduced to 15% or less of baseline.Monofilament of 0.35 mm diameter,5 mm coated with silicone rubber coated was more reliable than those we once used,because it had smooth,soft,and flexible tip,which could reduce the risk of vessel injury and intracranial bleeding.The model was produced success in 44 of 50 rats,achievement ratio was 88%.Conclusion The cerebral blood flow reduction to 15% or less of baseline is a key factor in suture methods for rat model of focal cerebral ischemia/reperfusion.Silicone-rubber coated monofilament is more reliable in the experiment.

Key words: Sprague-Dawly rat, suture method, focal cerebral ischemia/reperfusion