The Influence of Hydrocortisone and Certain Electrolyte Solutions upon the Phagocytic and Bactericidal Capacity of Leukocytes Obtained from Peritoneal Exudate of Rats

Abstract

Summary The bactericidal capacity of leukocytes obtained from the peritoneal exudate of rats both untreated and pretreated with intramuscular cortisol was studied in vitro. Phagocytosis of a mouse virulent, encapsulated strain of type I pneumococcus and an avirulent type XIV Streptococcus was accomplished on a suitable surface and the viability of engulfed organisms assayed in slide cultures. Under these conditions, with a phosphate buffer of high ionic strength to suspend the bacterium-cell mixtures, it was found that pretreatment with cortisol at a level of either 1.75 or 7.0 mg/kg for 3 days or longer impaired the ability of PMNG to kill bacteria. Further investigation revealed that suspending solutions of lower ionic strength increased the intensity of phagocytosis and the killing efficiency of exudate leukocytes from untreated animals and abolished the effects of glucocorticoid pretreatment. An explanation for this was not evident although there was evidence to suggest that the divalent cation, magnesium, restored bactericidal efficiency previously impaired in the high ionic phosphate buffer. From this information it is suggested that pretreatment with cortisol may induce a metabolic change at the molecular level that interferes with the killing and destruction of ingested bacteria. It is conceivable that this alteration may contribute to an enhancement of infection associated with glucocorticoid previously noted in experimental animals and in man.