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A Microplate Assay to Assess Chemical Effects on RBL-2H3 Mast Cell Degranulation: Effects of Triclosan without Use of an Organic Solvent
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Binding of aminoglycoside antibiotics by degranulating mast cells

G Decorti1, L Candussio, F B Klugmann

  • 1Department of Biomedical Sciences, Faculty of Medicine, Trieste, Italy.

Chemotherapy
|January 1, 1997
PubMed

Insights

Aminoglycoside antibiotics like gentamicin do not enter most cells. However, mast cell degranulation exposes binding sites, increasing aminoglycoside uptake via ionic interactions with granular matrix.

Area of Science:

  • Pharmacology
  • Cell Biology
  • Immunology

Background:

  • Aminoglycoside antibiotics are polycationic and exhibit poor cell penetration at physiological pH.
  • Previous studies show limited intracellular concentrations of aminoglycosides in intact cells.

Purpose of the Study:

  • To investigate the uptake mechanism of aminoglycosides in mast cells.
  • To determine the relationship between mast cell degranulation and aminoglycoside intracellular concentrations.

Main Methods:

  • Incubation of intact mast cells with gentamicin and tobramycin.
  • Induction of mast cell degranulation using compound 48/80, Adriamycin, or concanavalin A.
  • Measurement of intracellular aminoglycoside concentrations and histamine release.
  • Analysis of aminoglycoside binding to isolated granular material.

Main Results:

  • Intact mast cells showed extremely low intracellular aminoglycoside concentrations.
  • Degranulation induced dose-dependent histamine release and significantly increased intracellular aminoglycoside levels.
  • Aminoglycoside uptake was proportional to histamine release, irrespective of the stimulus type.
  • Aminoglycoside binding to granular material mimicked binding in degranulating mast cells.

Conclusions:

  • Aminoglycoside uptake into mast cells is facilitated by degranulation.
  • Ionic interactions between aminoglycosides and exposed granular matrix components drive this uptake.
  • Further studies are needed to elucidate the functional significance of this phenomenon.

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