OBJECTIVETo study the correlation between arachidonic acid (AA) and acute red blood cells damage in rats, and to build a model with hidden blood loss in vivo, and to explore the pathological mechenism of hidden blood loss.

METHODSA total of 50 male adult Sprague-Dawley rats weighing (200 ± 20) g were randomly divided into five groups (n = 10): control group and four experimental groups. The rats in the experimental groups were given 0.5 ml different concentrations of AA dilu- ents, 5, 10, 20, 40 mmol/L respectively. The blood samples were collected from orbital venous at the beginning and 24, 48, 72 hours after administration. Then the changes of hemoglobin (Hb) ,red blood cell count (RBC), glutathione peroxidase (GSH- PX) activity, total superoxide dismutase (T-SOD) activity and hydrogen peroxide (H202) in the blood samples were tested.

RESULTSSignificant hidden blood loss occurred when the concentration was 10 mmol/L in the experimental group, with the RBC and Hb sharply reduced in blood samples. The Hb and RBC were reduced in all the experimental groups and control group at 24 hours after administration, while in the experimental groups they changed more obviously. The GSH-PX activity, T-SOD activity and H₂O₂were also significantly reduced in all groups, and the changes showed significant differences. The Hb and RBC were relatively stable in the control group and the experimental groups at 48 hours after administration; while GSH-PX activity, T-SOD activity and H₂O₂were all significantly decreased, and the changes in the experimental groups were more notable.

CONCLUSIONElevated levels of AA in the blood causes oxidative stress in the red blood cells, leading to the damage of red blood cells and hemoglobin, which is responsible for hidden blood loss.