Protective effects of fetal neocortical transplants on cognitive function and neuron size in rats with congenital micrencephaly.
The rat with micrencephaly, produced by prenatal exposure to methylazoxymethanol, provides a useful model to study neurobehavioral abnormalities associated with congenital brain defects. The micrencephalic animals have a life-long learning impairment. As they age, their already impaired learning competence deteriorates further. To determine whether the aging-associated functional deterioration could be ameliorated by a neural transplant, micrencephalic rats bearing solid transplants of normal fetal neocortical tissue since infancy were evaluated on a visual pattern discrimination learning at 15 months and a spatial navigation test at 24 months of age. The transplant-bearing rats learned both tasks significantly better than the micrencephalic rats without transplants. Morphometric analyses revealed that cortical pyramidal neurons were larger in the transplant-bearing rats than in micrencephalic rats without transplants. The life-long presence of a transplant appeared to have protected the micrencephalic brain against aging-associated deterioration. This is the first demonstration that a neural transplant, placed in a congenitally defective infant brain, can ameliorate aging-associated cognitive deficits.
Lee
M H
MH
New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314, USA. mhlee@con2.com
Rabe
A
A
D000818:Animals; D016380:Brain Tissue Transplantation / Q000502:physiology*; D002452:Cell Count; D002540:Cerebral Cortex / Q000637:transplantation*; D003071:Cognition / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D016332:Fetal Tissue Transplantation / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008568:Memory / Q000502:physiology; D008831:Microcephaly / Q000473:pathology / Q000523:psychology / Q000628:therapy*; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure*; D051381:Rats