title: Effects of liposome-encapsulated ciprofloxacin on phagocytosis, nitric oxide and intracellular killing of Staphylcoccus aureus by murine macrophages.
abstract: The effects of liposome-encapsulated ciprofloxacin on phagocytosis, nitric oxide production and intracellular killing of Staphylococcus aureus in murine macrophages were evaluated in this study. Mice were pretreated with three daily doses of liposome-encapsulated ciprofloxacin (45 mg/kg body weight/dose, intraperitoneal injection). At day 3 post drug administration, peritoneal macrophages were harvested by peritoneal lavage, and the phagocytic activity of the macrophages was determined by a chemiluminescence assay using opsonized zymosan particles. The phagocytic activity was found to be 7-fold higher in the liposome-encapsulated ciprofloxacin-treated group when compared to the untreated control group. For S. aureus-infected macrophages incubated with liposomes containing subinhibitory concentrations of ciprofloxacin (0.05 to 0.25 microg/mL), there were significant increases (up to 40 microM) in the levels of nitrite (NO2-, an end product of nitric oxide synthesis), and concommitant decreases (2-3 log) in the intracellular concentrations of S. aureus. Peak nitrite levels (20-40 microM) were produced when concentrations of liposome-encapsulated ciprofloxacin used were 0.1 to 0.25 microg/mL. These results suggest that liposome-encapsulated ciprofloxacin may have profound effects on the immunological functions of macrophages.
authors.affiliation: Medical Countermeasures Section, Defence Research Establishment Suffield, Alberta, Canada.
authors.forename: J P
authors.initials: JP
authors.lastname: Wong
authors.forename: G
authors.initials: G
authors.lastname: Schnell
authors.forename: M
authors.initials: M
authors.lastname: Simpson
authors.forename: E
authors.initials: E
authors.lastname: Saravolac
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000494:pharmacology; D002939:Ciprofloxacin / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004339:Drug Compounding / Q000379:methods*; D005260:Female; D008081:Liposomes / Q000008:administration & dosage / Q000494:pharmacology; D008163:Luminescent Measurements; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000382:microbiology; D008567:Membranes, Artificial; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000276:immunology
chemical_list: D000890:Anti-Infective Agents; D008081:Liposomes; D008567:Membranes, Artificial; D009569:Nitric Oxide; D002939:Ciprofloxacin