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Effect of organophosphorus compound intoxication on auditory brainstem response in mini pigs
W Bergler1, C Juncker, G Petroianu
1Department of Otorhinolaryngology, University of Mannheim, Germany.
Abstract:
Organophosphorus compounds (OPC) are widely used as insecticides and cause a high number of acute and chronic intoxications in man. Their toxicological properties lead among others to disturbances of the central nervous system. Hearing disturbances have been reported after chronic exposure to OPC, and changes in bioelectric brain activity have been observed during the acute state of intoxication. The EEG showed no characteristic alterations. We performed a threshold auditory brainstem response (ABR) in 12 mini pigs before, during and after paraoxon (a typical OPC) intoxication with a high dose of 27 mg/kg BW. During the application of paraoxon we saw a prolongation of the interpeak latencies Jewett I-V of approximately 1 ms. A threshold shift of 10-20 dB was seen in 8 animals. After the application, while the systemic effect of the paraoxon intoxication was still apparent, the threshold shift disappeared except for 2 animals and the prolongation of the interpeak latencies could not be observed any more. No characteristic signs of paraoxon intoxication could be seen in the ABR after the application was completed. Acute intoxication with an OPC only leads to temporary, limited hearing impairment and increased interpeak latency. We could not observe characteristic changes in the ABR corresponding to the state of intoxication.
Insights
Acute organophosphorus compound (OPC) intoxication causes temporary hearing impairment and prolonged brainstem response latencies in mini pigs. These auditory effects resolve as the intoxication subsides, with no lasting ABR changes observed.
Area of Science:
- Neurotoxicology
- Auditory Neuroscience
- Toxicology
Background:
- Organophosphorus compounds (OPCs) are common insecticides linked to central nervous system disturbances.
- Hearing impairment and altered brain activity are reported following chronic and acute OPC exposure, respectively.
- Previous EEG studies showed no characteristic alterations during acute OPC intoxication.
Purpose of the Study:
- To investigate the effects of acute organophosphorus compound (OPC) intoxication on auditory brainstem response (ABR) in mini pigs.
- To determine if ABR can detect characteristic changes during acute OPC exposure.
Main Methods:
- 12 mini pigs underwent threshold auditory brainstem response (ABR) testing.
- ABR was measured before, during, and after paraoxon (a typical OPC) intoxication at a high dose (27 mg/kg BW).
- Interpeak latencies (Jewett I-V) and threshold shifts were analyzed.
Main Results:
- Paraoxon intoxication caused a temporary prolongation of interpeak latencies (Jewett I-V) by approximately 1 ms.
- A 10-20 dB threshold shift in hearing was observed in 8 animals during intoxication.
- These auditory changes resolved after paraoxon application, except in 2 animals, with no characteristic ABR signs remaining post-intoxication.
Conclusions:
- Acute OPC intoxication induces transient hearing impairment and increased interpeak latencies.
- Auditory brainstem response (ABR) changes during acute OPC intoxication are temporary and limited.
- No characteristic ABR alterations corresponding to the intoxication state were observed after the acute phase.