Antibiotics Reduce Retinal Cell Survival In Vitro

Area of Science:

• Ophthalmology
• Neuroscience
• Cell Biology

Background:

• Antibiotics like gentamicin and penicillin are standard in retinal cell cultures for transplantation research.
• In vivo, high-dose gentamicin is known to be neurotoxic to the retina.
• The in vitro toxicity of commonly used antibiotic concentrations on retinal cells remains largely uncharacterized.

Purpose of the Study:

• To investigate the in vitro toxicity of various antibiotics on retinal cells.
• To determine if commonly used doses of gentamicin and other antibiotics affect retinal cell survival, neuritic growth, and Mueller cell health.
• To assess the impact of these antibiotics on neuronal regeneration in cell culture.

Main Methods:

• Retinal cells from tiger salamanders were cultured and treated with gentamicin, streptomycin, antibiotic/antimycotic (containing amphotericin B), and penicillin G at manufacturer-recommended levels.
• Toxicity was assessed at 2 hours and 7 days by evaluating retinal neuron survival, photoreceptor neuritic growth (presynaptic varicosities), and Mueller cell survival and morphology.
• Immunolabeling for rod opsin, glial fibrillary acidic protein, and synaptophysin was used to quantify cell types and structures.

Main Results:

• All tested antibiotics significantly reduced neuronal cell density and the number of presynaptic varicosities in both rod and cone photoreceptors compared to controls.
• Rod photoreceptors showed greater sensitivity to gentamicin than cone photoreceptors.
• Penicillin G exhibited the least inhibition, while amphotericin B was the most toxic. Mueller cell survival and healthy morphology were compromised by all treatments.

Conclusions:

• Even microgram doses of commonly used antibiotics and antimycotics can exert neurotoxic effects on retinal cells in vitro.
• These drugs can inhibit vital cellular processes like neuritic regeneration, potentially confounding results in retinal cell culture studies.
• Researchers should carefully consider the potential toxicity of antibiotics when designing in vitro experiments involving retinal cells, particularly for transplantation research.