- Streptomycin is a widely used antibiotic in cell culture, particularly valued for its effectiveness against Gram-negative bacteria. It works by binding to the 30S subunit of bacterial ribosomes, where it disrupts protein synthesis by causing errors in mRNA translation. This property makes it effective in killing or inhibiting bacteria, especially when used in combination with penicillin. However, because of the evolutionary origin of mitochondria, which descended from ancestral prokaryotes, mitochondria also contain ribosomes that resemble bacterial 70S ribosomes rather than the 80S ribosomes found in the eukaryotic cytoplasm.
- Due to this similarity, streptomycin can, in theory, interact with mitochondrial ribosomes, especially in sensitive cell types. This interaction may impair mitochondrial protein synthesis, particularly of components essential for oxidative phosphorylation. As a result, mitochondrial function—such as ATP production and energy metabolism—could be compromised if the antibiotic is used at high concentrations or over extended periods. In more sensitive or metabolically active cells, this could lead to mitochondrial stress or reduced cell viability.
- However, under standard cell culture conditions, streptomycin is typically used at concentrations between 50–100 µg/mL, which are generally considered safe. At these levels, the antibiotic has minimal to no detectable effect on mitochondria in most commonly used cell lines. Adverse mitochondrial effects are more likely to occur if streptomycin is used improperly—at high doses, for prolonged periods, or in combination with other mitochondrial-inhibiting agents.
