Early neural grafts transiently reduce the behavioral effects of radiation-induced fascia dentata granule cell hypoplasia.
X-irradiation of the neonatal rat hippocampus produces a selective hypoplasia of fascia dentata granule cells, locomotor hyperactivity, perseverative movements and deficits in passive avoidance. We previously reported that transplantation of fetal hippocampal tissue into the adult (age = 182 +/- 4 days) brain produced a partial recovery of these behavioral deficits. Since graft/host interconnections are more prominent when transplants are conducted soon after radiation-induced hippocampal damage, in this study we transplanted hippocampal or cerebral cortex neurons when host rats were 33 +/- 5 days of age (i.e. only 16 days after radiogenic brain damage). Behavioral evaluations were conducted 80 and 182 days after transplantation or surgical control procedures. In the first test series only, selective components of locomotion (e.g. stereotypy and total distance traveled) and perseverative turning (e.g. mean bout length and turning speed topography) were normalized by the hippocampal grafts. Radiation-induced changes in passive avoidance were less prominent in these studies than in past experiments. Still, transplantation of hippocampal tissue improved performance on this learning task as well. Cerebral cortex grafts did not produce reliable improvements in most behavioral measures. These data suggest that hippocampal grafts placed soon after X-ray induced fascia dentata hypoplasia reduce a broad range of behavioral deficits. However, these benefits are transient and, for the most part, depend on the use of transplant tissues homologous with those damaged.
Mickley
G A
GA
Behavioral Sciences Department, Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145.
Ferguson
J L
JL
Mulvihill
M A
MA
Nemeth
T J
TJ
D000818:Animals; D001362:Avoidance Learning / Q000528:radiation effects*; D001921:Brain / Q000502:physiology / Q000528:radiation effects*; D016380:Brain Tissue Transplantation / Q000502:physiology*; D002540:Cerebral Cortex / Q000637:transplantation; D016332:Fetal Tissue Transplantation / Q000502:physiology; D006624:Hippocampus / Q000502:physiology / Q000528:radiation effects* / Q000637:transplantation; D008297:Male; D009043:Motor Activity / Q000528:radiation effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000528:radiation effects*; D014965:X-Rays