Chad T Andicochea, Ashley K Ramsey and John R Martin
Objective: Elevated aggression and poor intelligence scores occur in children with BLLs (Blood Lead Levels) lower than 10 μg/dL while Pb-exposed cats show increased aggressive behavior with BLLs of 10 μg/dL. This increased aggression in cats may be associated with the development of hyper-spiny neurons observed in the motor cortex, hippocampus and cerebellum of kittens with BLLs<1.2 μg/dL. These results suggest that lead ingestion by kittens might result in learning and behavioral deficits similar to those observed in lead-burdened children.
Methods: To test this, kittens were treated (20 mg/kg/day, lead acetate or distil water via esophageal intubation) from Postnatal Day (PND) 1 to 7. At 8 and 10 weeks of age, the kittens were tested in a reversal T-maze, an open-field, and a free-fall test.
Results: 8 weeks old Pb-treated kittens showed a delay in learning as demonstrated by a significant higher number of Incorrect Arm Choices (IACs) in the T-maze that returned to control levels in 10 weeks old kittens. No differences occurred between the two groups at 8 and 10 weeks of age in the open-field or free-fall tests.
Conclusion: The impairment in the reversal T-maze suggests a Pb-induced delay in learning, which compares favourably with current understanding of delayed learning in Pb-poisoned children.