RESUMO
Objective Effective tissue perfusion fixation plays an important role in immunofluorescence experiments and other studies .The aim of this study was to modify the method for perfusion fixation of rat brain tissues and improve the efficiency of the procedure . Methods Conventional thoracotomy was modified by cutting the skin from the xiphoid along the mediventral line to the lower jaw to expose both sides of the thorax and then freeing the chest wall .The tip of the infusion needle was cut off and the needle in-serted into the left ventricle , pushed to the ascending aorta , and fixed there to prevent sliding .Perfusion and fixation began after tho-racic aortic occlusion.The regulatory valve was opened , followed by infusion of 0.9%physiological saline and cutting the right atrial appendage .When the perfusate became clear , the infusion tube was replaced , without removal of the needle , and fixed with 4%paraformaldehyde .The fixation process was slowed down gradually till the neck became stiff , which indicated its completion . Results The head, neck and upper limbs were all fixed desirably by this method , which shortened the operation time , saved 4%paraformalde-hyde, and achieved satisfactory immunofluorescence results as compared with conventional procedures . Conclusion The modified method is simple , obviously improves the results of perfusion fixation of rat brain tissue , and therefore deserves to be popularized .