To investigate the role and the secondary significance of
erythromycin concentrated within polymorphonuclear neutrophils
(PMNs). PMNs were incubated in vitro with
erythromycin. The dynamic changes of the intracellular/extracellular erythromycin
concentration ratio (C/E) were detected during the incubating period and after PMNs were activated, meanwhile the PMN membrane bound leukocyte elastase (HLE) that marked the inflammatory response of PMN was measured by immnofluorescence technique. The difference of erythromycin concentration in the bronchoalveolar lavage fluid (BALF) between normal rats and rats with low respiratory track infection was detected after the experimental rats were injected intravenously with the PMNs in which erythromycin was concentrated. The erythromycin C/E achieved the peak (16/1) within 60min, meanwhile the PMN membrane activated by stimulation, its C/E decreased while the membrane bound HLE increased, but the extent of this increase was lower than that of normal PMN′s. The erythromycin concentration of BALF which collected from the rats with low airway infection was higher than that from normal rats. Erythromycin could be accumulated within PMN quickly. The accumlation could induce the decrease of PMN basic activity and the inhibition of stimulative activity. The part release of intracellular erythromycin could be induced by stimulating the PMNs. This characteristics is helpful to the release of the erythromycin accumulated within PMNs in the direction of infective site.