Objective:To observe the effect of old RBCs transfusion on cognitive function in rats and the improvement effect of mi -nocycline.Methods: Male SD rats at the age of 6 months were randomly divided into 4 groups.The RBCs were obtained from male rats by centrifuging the total blood and stored at 4℃.The rats of fresh RBCs group (group F) were transfused with the RBCs stored for 1 day.The rats of old RBCs group (group O) were transfused with the RBCs stored for 7 days.The rats of treatment group (group T) received 40 mg· kg-1 minocycline with intraperitoneal injection before the transfusion .The rats of the control group ( group C) were transfused with the normal saline .The brain levels of IL-1βand IL-6 were determined with Quantikine ELISA kits in 24 hours after the blood transfusion (n=6).The rats were subjected to Barnes maze tests after 1 week of the blood transfusion (n=10).Results:The brain levels of IL-1βand IL-6 in group O were higher than those in group C and F (P<0.05), which were lower in group T than those in group O(P<0.05).The rats of group O spent longer time finding the target box than those of group C and F in the Barnes maze (P<0.05), and the time was shorter in group T than that in group O (P<0.05).Conclusion: Old RBCs transfusion plays a role in neuro-inflammation and induces cognitive dysfunction in rats , which may be improved by minocycline .