Developmental neurotoxicity guideline procedures - Neurobehavioral testing of pre-weaning rat pups in a standardized arena

SOT 2024 -- Developmental neurotoxicity (DNT) studies are a regulatory requirement for the testing of chemicals that may cause adverse neurodevelopmental outcomes. EPA OPPTS 870.6300 and OECD 426 test guidelines require testing laboratories to demonstrate competence and inter-observer reliability in the detection of effects in offspring exposed pre- and post-natally to chemicals with the use of positive controls. Test procedures on the DNT study include an examination of the offspring outside of the home cage on Post-Natal Day (PND) 4, 11, 21, 35 and 45. From PND 21, the observational arena used for the Functional Observational Battery (FOB) assessment in adults is considered appropriate. However, young pups have limited movement, with pups on PND 4 incapable of any co-ordinated locomotor activity. This work was performed in order to demonstrate that the FOB procedure used at Labcorp is suitable for performing regulatory DNT assessments on pre-weaning rat pups on PND 4 and 11. In addition, this work demonstrated the effectiveness and reliability of the staff performing the FOB assessments.