Thimerosal: a versatile sulfhydryl reagent, calcium mobilizer, and cell function-modulating agent

Area of Science:

• Biochemistry
• Cell Biology
• Toxicology

Background:

• Thimerosal is widely used as an antiseptic and preservative due to its antibacterial properties.
• It functions as a sulfhydryl reagent and calcium-mobilizing agent in biomedical research.
• Its mercury content is key to its sulfhydryl reactivity, though mechanisms are not fully elucidated.

Purpose of the Study:

• To review the literature on thimerosal's effects on cellular functions.
• To explore the mechanisms underlying thimerosal's actions, focusing on calcium mobilization and sulfhydryl reactivity.
• To summarize thimerosal's impact on specific cell types like platelets and neutrophils.

Main Methods:

• Literature review of studies investigating thimerosal's biological effects.
• Analysis of research on thimerosal's interaction with sulfhydryl groups, often assessed using dithiothreitol (DTT).
• Examination of studies detailing thimerosal's impact on intracellular and extracellular calcium dynamics.

Main Results:

• Thimerosal triggers calcium release from intracellular stores (InsP3- and ryanodine-sensitive) and subsequent extracellular influx.
• Concentration-dependent effects are observed in permeabilized cells: low concentrations stimulate, high concentrations inhibit calcium release.
• In intact cells, thimerosal modulates platelet aggregation, arachidonic acid metabolism, serotonin release, and neutrophil functions including migration and exocytosis.

Conclusions:

• Thimerosal's effects on cell functions are linked to calcium mobilization and sulfhydryl group interactions.
• Low concentrations can activate neutrophil migration and enzyme release, while higher concentrations inhibit these processes.
• The thiosalicylic acid moiety of thimerosal contributes to its effects on neutrophil migration.