title: Maternal Exposure to Valproic Acid Primarily Targets Interneurons Followed by Late Effects on Neurogenesis in the Hippocampal Dentate Gyrus in Rat Offspring.
abstract: Valproic acid (VPA) is used to establish models of experimental autism. The present study investigated the developmental exposure effect of VPA on postnatal hippocampal neurogenesis in accordance with the exposure scheme of OECD Test Guideline 426 adopted for developmental neurotoxicity. Pregnant rats were administered drinking water containing 0, 667, or 2000 ppm VPA from gestational day 6 until day 21 post-delivery. In the subgranular zone (SGZ) and granule cell layer (GCL) of offspring, the number of granule cell lineage subpopulations remained unchanged upon weaning. However, in the hilus of the dentate gyrus, the number of reelin+interneurons decreased at ≥667 ppm, and the number of PVALB+or GAD67+interneurons decreased at 2000 ppm. Conversely, Reln and Gad1 transcript levels increased at 2000 ppm, but Pvalb and Grin2d decreased, in the dentate gyrus. At the adult stage, PCNA+proliferating SGZ cells, NeuN+postmitotic SGZ/GCL neurons, and ARC+or COX2+GCL neurons increased at ≥667 ppm. In the dentate hilus, decreases in GAD67+interneuron subpopulations and Grin2d transcript levels sustained at 2000 ppm. These results suggested that VPA primarily targets interneurons by developmental exposure, and this is followed by late effects on granule cell lineages, likely by influencing SGZ cell proliferation and synaptic plasticity. A reduced population of reelin+or PVALB+interneurons did not affect distribution of granule cell lineage subpopulations upon weaning. The late effect on neurogenesis, which resulted in increased GCL neurons, might be the result of a sustained decrease in GAD67+interneurons expressing NR2D encoded by Grin2d.
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.|Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-Shi, Gifu, 501-1193, Japan.
authors: Yousuke
authors: Y
authors: Watanabe
authors: Laboratory of Veterinary Toxicology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.
authors: Tomoaki
authors: T
authors: Murakami
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.
authors: Masashi
authors: M
authors: Kawashima
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.
authors: Yasuko
authors: Y
authors: Hasegawa-Baba
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.|Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-Shi, Gifu, 501-1193, Japan.
authors: Sayaka
authors: S
authors: Mizukami
authors: Chemicals Evaluation and Research Institute, Japan, 1-4-25 Koraku, Bunkyo-Ku, Tokyo, 112-0004, Japan.
authors: Nobuya
authors: N
authors: Imatanaka
authors: Chemicals Evaluation and Research Institute, Japan, 1-4-25 Koraku, Bunkyo-Ku, Tokyo, 112-0004, Japan.
authors: Yumi
authors: Y
authors: Akahori
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan.
authors: Toshinori
authors: T
authors: Yoshida
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-Shi, Tokyo, 183-8509, Japan. mshibuta@cc.tuat.ac.jp.
authors: Makoto
authors: 0000-0003-3417-9697
authors: M
authors: Shibutani
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects; D002525:Cerebellar Cortex / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000473:pathology; D002540:Cerebral Cortex / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000473:pathology; D018891:Dentate Gyrus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D060766:Drinking Water; D005260:Female; D007395:Interneurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D018811:Maternal Exposure; D055495:Neurogenesis / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011897:Random Allocation; D051381:Rats; D000091042:Reelin Protein; D055153:Stem Cell Niche / Q000187:drug effects / Q000502:physiology; D014635:Valproic Acid / Q000633:toxicity*
chemical_list: D060766:Drinking Water; D000091042:Reelin Protein; C000717129:Reln protein, rat; D014635:Valproic Acid
keywords: Developmental neurotoxicity (DNT); Hippocampal neurogenesis; Rat; Valproic acid (VPA); γ-Aminobutyric acid (GABA)-ergic interneuron