OBJECTIVETo explore the activation of polymorphonuclear cells (PMNs) and vascular endothelial cells co-cultured with and stimulated by lipopolysaccharide.

METHODSPMNs in concentration of 2 x 10(6)/ml isolated from healthy volunteers by Percoll gradient were added to monolayer of ECV-304 cells grown to confluency, then different groups were prepared according to final concentration of lipopolysaccharide. The morphological change was observed under invert microscope. The changes in TNFalpha and IL-6 levels of the supernatant of the cultured cells were determined at 4, 8, 12 and 24 hours after culturation.

RESULTSThe TNFalpha production of cultured pure ECV-304 exhibited no remarkable change when stimulated by different concentrations of LPS. But the TNFalpha production of the ECV-304 increased significantly when co-cultured with PMNs at 4 hr and stimulated by LPS in concentration of 10 micro g/ml, and increased at 8 hours and lasted up to 24 hours of culturation in higher levels (P < 0.05). The IL-6 production of cultured pure ECV-304 increased obviously along with the increase of LPS concentration, and it showed no change when PMNs co-cultured with ECV-304. While the IL-6 level in the supernatant of co-cultured ECV-304 with PMNs increased sharply when stimulated by both low (100 ng/ml) and high (1 micro g/ml) concentrations of LPS and maintained at high levels up to 24 hours of culturation. The higher the concentration of LPS was, the quicker the IL-6 level increased.

CONCLUSIONCo-cultured PMNs and endothelial cells could be activated and activation state could be maitained by low concentrations of LPS.