Triethylbenzene-induced sensorimotor neuropathy in rats

Area of Science:

• Neuroscience
• Toxicology
• Organic Chemistry

Background:

• Triethylbenzenes (TEBs) are aromatic hydrocarbons with potential industrial applications.
• Understanding the specific toxicity of TEB isomers is crucial for risk assessment.
• Previous research has not clearly delineated the neurotoxic potential of different TEB isomers.

Purpose of the Study:

• To investigate the neurotoxic effects of two specific triethylbenzene isomers, 1,2,4-TEB and 1,3,5-TEB.
• To compare the electrophysiological changes induced by oral administration of these isomers in rats.
• To identify potential structure-activity relationships related to TEB neurotoxicity.

Main Methods:

• Male Sprague-Dawley rats were orally administered 1,2,4-TEB or 1,3,5-TEB (200 or 400 mg/kg) four days per week for eight weeks.
• Electrophysiological assessments, including motor and sensory conduction velocities (MCV, SCV) and action potential amplitudes (AMAP, ASAP), were performed bi-weekly.
• Visual inspection for physical changes such as skin discoloration and urine color was conducted.

Main Results:

• Oral administration of 1,2,4-TEB resulted in a time- and dose-dependent decrease in MCV, SCV, AMAP, and ASAP.
• Rats treated with 1,2,4-TEB showed bluish skin discoloration and greyish-green urine.
• No significant electrophysiological changes or physical abnormalities were observed in rats treated with 1,3,5-TEB.

Conclusions:

• 1,2,4-Triethylbenzene is a neurotoxic isomer of TEB.
• The ortho-positioning of two ethyl groups on the aromatic ring appears critical for the observed neurotoxic and chromogenic properties.
• 1,3,5-Triethylbenzene does not exhibit similar neurotoxic effects, suggesting isomer-specific toxicity.