#624 28-day delayed neurotoxicity (hen)
Objective of the study
The objective of the 28-day delayed neurotoxicity study is to assess the potential of certain classes of substances to cause delayed neurotoxicity or delayed polyneuropathy following repeated exposure.
Circumstances under which the study is recommended to be required
The 28-day delayed neurotoxicity study is recommended if results of acute neurotoxicity study indicate significant statistical or biological effects or if other available data indicate the potential for this type of delayed neurotoxicity, as determined by the responsible authority.
Test organism
The 28-day delayed neurotoxicity study is conducted with the adult domestic hen.
Test substance
Technical grade active ingredient
Typical endpoints of the study
Typical endpoints of the 28-day delayed neurotoxicity study include (among others):
- toxic response data, including mortality;
- nature, severity and duration of clinical observations (whether reversible or not);
- no-observed-adverse effect level;
- biochemical findings;
- histopathological findings.
Test guidelines
The following test guidelines may be used for the 28-day delayed neurotoxicity study:
- OECD Guidelines for the Testing of Chemicals. Test No. 419: Delayed neurotoxicity of organophosphorus substances – 28-day repeated dose study
- US EPA Health Effects Test Guidelines. OPPTS 870.6100 Acute and 28-day delayed neurotoxicity of organophosphorus substances
- EC Testing Method B.38. Delayed neurotoxicity of organophosphorus substances 28-day repeated dose study. Council Regulation (EC) No 440/2008.