Truncated IGF-1 exerts trophic effects on fetal brain tissue grafts.
Truncated IGF-1 (tIGF-1), a form of IGF-1 identified in the human brain, has been suggested, from in vitro experiments, to exert neurotrophic effects on developing fetal brain tissue. We studied the effects of tIGF-1 and IGF-1 on small defined areas of the developing central nervous system by using the in vivo model of intraocular transplantation which allows for direct observations of graft survival and growth. Truncated IGF-1 was found to significantly enhance the growth of fetal spinal cord (Embryonic Day (E) 14) and parietal cortex (E16-17) grafts transplanted to the anterior chamber of the eye of adult rats. tIGF-1 increased the volume of cerebral cortex grafts by approximately 100% and of E14 spinal cord grafts by approximately 50%. E18 spinal cord grafts and hippocampal grafts were not stimulated by tIGF-1 as compared to controls given HSA. Effects in cortex were seen with tIGF-1 using concentrations down to at least 10 ng/microliters. Interestingly, intact IGF-1 had no effect on cortical grafts. These findings show for the first time, using an in vivo system, that tIGF-1 is a potent stimulator of growth of grafted fetal cortex cerebri and spinal cord and suggest a possible role for endogenous tIGF-1 in cortical and spinal cord development.
Giacobini
M M
MM
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
Olson
L
L
Hoffer
B J
BJ
Sara
V R
VR
D000818:Animals; D002455:Cell Division; D005123:Eye; D006624:Hippocampus / Q000166:cytology / Q000196:embryology / Q000637:transplantation; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D009417:Nerve Tissue / Q000637:transplantation*; D009457:Neuroglia / Q000166:cytology; D009474:Neurons / Q000166:cytology; D010296:Parietal Lobe / Q000166:cytology / Q000196:embryology / Q000637:transplantation; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000494:pharmacology*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000637:transplantation; D016042:Transplantation, Heterotopic
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I