OBJECTIVETo investigate the effects of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) on the apoptosis of thymic and splenic lymphocytes in rats with sepsis.

METHODSA total of 80 female Sprague-Dawley rats aged 7-8 weeks were randomly divided into model group, conventional lipid emulsion group (0.1 g/kg daily), low-dose ω-3 PUFAs group (0.1 g/kg daily), middle-dose ω-3 PUFAs group (0.2 g/kg daily), and high-dose ω-3 PUFAs group (0.3 g/kg daily). Cecal ligation and puncture were used to establish a rat model of sepsis. The treatment groups were then given tail vein injection of lipid emulsion or glucose diluents of ω-3 PUFAs at different doses, and the model group was given glucose injection via the tail vein at the same dose. According to the time of sacrifice, each group was further divided into 24-hour and 72-hour subgroups, with 8 rats in each subgroup. Hematoxylin and eosin staining was used to observe the pathological changes in the thymus and spleen. TUNEL was used to measure the apoptosis rates of thymic and splenic lymphocytes.

RESULTSIn the three ω-3 PUFAs groups, the rats had a complete thymic lobular structure and clear structures of the cortex and medulla. In the model and the conventional lipid emulsion groups, the boundaries of the cortex and medulla were unclear and the number of lymphocytes was significantly reduced. In the ω-3 PUFAs groups, the structure of the red and white pulp of the spleen was maintained with the presence of splenic follicles, while in the model and the conventional lipid emulsion groups, the structure of the red and white pulp of the spleen was disordered and splenic follicles were significantly reduced or disappeared. Compared with the model and the conventional lipid emulsion groups, the ω-3 PUFAs groups showed significant reductions in the apoptosis rates of thymic and splenic lymphocytes at 24 and 72 hours (P<0.01). Compared with the low-dose ω-3 PUFAs group, the high-dose ω-3 PUFAs group had significantly reduced apoptosis rates of splenic lymphocytes at 24 and 72 hours (P<0.05).

CONCLUSIONSω-3 PUFAs can reduce the apoptosis of thymic and splenic lymphocytes in rats with sepsis in a dose-dependent manner.