Age-dependent sensitivity of the rat to neurotoxic effects of streptomycin

Area of Science:

• Neuroscience
• Toxicology
• Developmental Biology

Background:

• Aminoglycoside antibiotics like streptomycin are crucial for treating bacterial infections.
• However, ototoxicity and neurotoxicity are known side effects of streptomycin.
• Understanding the developmental timing of susceptibility is vital for safe therapeutic use.

Purpose of the Study:

• To determine the critical developmental periods of susceptibility to streptomycin-induced ototoxicity and dyskinesia in rats.
• To compare the sensitivity of the cochlea versus the central nervous system/vestibular system to streptomycin during development.

Main Methods:

• Preweanling and weanling rats were administered streptomycin sulfate (300 mg/kg s.c.) for varying durations.
• Body movement and hearing were assessed starting from 8 days of age for up to 17 weeks.

Main Results:

• Abnormal movements and deafness were observed exclusively in rats treated during the preweaning period.
• The highest sensitivity to streptomycin-induced deafness occurred between 5 and 11 days of age.
• The greatest sensitivity to streptomycin-induced abnormal movements occurred between 2 and 11-17 days of age.

Conclusions:

• The preweaning period is a critical window for streptomycin-induced neurotoxicity and ototoxicity in rats.
• The cochlea is more vulnerable to streptomycin toxicity than the vestibular or central sites responsible for movement abnormalities during early development.