Nycthemeral variations on LPS- and BCG-induced PMN migration in normal mice

This study was performed to determine whether temporal variations could exist in polymorphonuclear neutrophil (PMN) migration induced by LPS or BCG in mice. LPS- and BCG-impregnated cell traps were implanted at 6 different times of the day and removed after 480 min. The PMN number per square unit (mm2) was counted and the results were expressed as means +/- S.E. in 8-10 mice. The results showed that nycthemeral variations occurred in both LPS- and BCG-induced PMN migration. Between 5.00 and 9.00 h a maximum value of 4210 +/- 270 and 1920 +/- 486 PMN/mm2 were obtained with BCG and LPS respectively; at 17.00 h a minimum value of 1300 +/- 270 with BCG and 396 +/- 127 PMN/mm2 with LPS were observed. There was no significant nycthemeral variation in saline-induced PMN migration.