Combined neurotrophic supplementation and caspase inhibition enhances survival of fetal hippocampal CA3 cell grafts in lesioned CA3 region of the aging hippocampus

• Published in: Neuroscience Vol. 109; no. 3; pp. 537 - 553
• Main Authors: Zaman, V, Shetty, A.K
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2002; Elsevier
• Subjects: 5′-bromodeoxyuridine; aging; Aging - drug effects; Aging - metabolism; Animals; Biological and medical sciences; Brain Tissue Transplantation - methods; Caspase Inhibitors; Caspases - metabolism; Cell Survival - drug effects; Cells, Cultured; Development. Senescence. Regeneration. Transplantation; Disease Models, Animal; Epilepsy, Temporal Lobe - pathology; Epilepsy, Temporal Lobe - surgery; Female; Fetus; Fundamental and applied biological sciences. Psychology; Graft Survival - drug effects; Graft Survival - physiology; hippocampal grafts; Hippocampus - drug effects; Hippocampus - surgery; Hippocampus - transplantation; hyperexcitability; Immunohistochemistry; Male; Nerve Growth Factors - pharmacology; neural transplantation; Neurons - drug effects; Neurons - enzymology; Neurons - transplantation; post-lesion plasticity; Pregnancy; Rats; Rats, Inbred F344; temporal lobe epilepsy; Vertebrates: nervous system and sense organs; KA, kainic acid; NPNFP, non-phosphorylated neurofilament protein; neural transplantation; TLE, temporal lobe epilepsy; NGF, nerve growth factor; HEPES, N-(2-hydroxyethyl)piperazine- N′-(2-ethanesulfonic acid); post-lesion plasticity; PBS, phosphate-buffered saline; ANOVA, analysis of variance; temporal lobe epilepsy; hippocampal grafts; DAB, 3,3′-diaminobenzidine; NT-3, neurotrophin-3; Ac-YVAD-cmk, acetyl-tyrosinyl-valyl-alanyl-aspartyl-chloro-methylketone; PB, phosphate buffer; hyperexcitability; BDNF, brain-derived neurotrophic factor; BrdU, 5′-bromodeoxyuridine; E, embryonic day; HBSS, Hanks’ balanced salt solution; PAP, peroxidase–anti-peroxidase; NeuN, neuron-specific nuclear protein; aging; ABC, avidin–biotin–complex; 5′-bromodeoxyuridine; Senescence; Rat; Enzyme; Rodentia; Central nervous system; Caspase; Transplantation; Peptidases; Neurotrophic factor; Vertebrata; Mammalia; Hydrolases; Fetus; Lesion; Kainic acid; Hippocampus; Brain (vertebrata)
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(01)00478-X

Fetal hippocampal CA3 cells show excellent survival when homotopically grafted into the kainic acid-lesioned CA3 region of the young adult hippocampus, a model of temporal lobe epilepsy. However, survival of these cells in the kainic acid-lesioned CA3 region of the aging hippocampus is unknown. We hypothesize that fetal CA3 grafts into the lesioned CA3 region of the middle-aged and aged hippocampus exhibit significantly diminished cell survival compared with similar grafts in the lesioned young adult hippocampus unless pre-treated and transplanted with factors that augment graft cell survival. We analyzed cell survival of 5′-bromodeoxyuridine-labeled embryonic day 19 CA3 grafts following their transplantation into the lesioned CA3 region of the middle-aged and aged rat hippocampus. Grafts were placed 4 days after an i.c.v. administration of kainic acid, and absolute cell survival of grafts was quantified 1 month after grafting using 5′-bromodeoxyuridine immunostaining of serial sections and the optical fractionator counting method. Grafts into both middle-aged and aged hippocampus exhibited analogous but significantly diminished cell survival (30% of injected cells) compared with similar grafts into the young adult hippocampus (72% cell survival). However, the extent of cell survival of CA3 grafts pre-treated and transplanted with a combination of neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 and the caspase inhibitor acetyl-tyrosinyl-valyl-alanyl-aspartyl-chloro-methylketone was significantly enhanced in both middle-aged and aged hippocampus (51–63% cell survival). These results underscore that aging impairs the conduciveness of the CA3 region for robust survival of homotopic fetal CA3 grafts after lesion. However, a combined neurotrophic supplementation and caspase inhibition significantly enhances survival of fetal CA3 cells in the lesioned aging hippocampus. Thus, pre-treatment and grafting of donor cells with a combination of factors that support growth of specific donor cells may considerably enhance survival and integration of fetal grafts into the lesioned aging CNS in clinical trials.