Culturas organotípicos rebanada de Estudios de Postnatal neurogénesis
Summary
Aquí se describe una técnica para el estudio de la neurogénesis postnatal del hipocampo mediante la técnica de cultivo de cortes organotípicos. Este método permite la manipulación in vitro de la neurogénesis adulta y permite la aplicación directa de agentes farmacológicos para el hipocampo cultivadas.
Abstract
Aquí se describe una técnica para el estudio de la neurogénesis postnatal del hipocampo en el cerebro de roedores mediante la técnica de cultivo de cortes organotípicos. Este método mantiene la morfología característica topográfica del hipocampo al tiempo que permite la aplicación directa de agentes farmacológicos a las desarrollo giro dentado del hipocampo. Además, los cultivos de cortes se pueden mantener durante un máximo de 4 semanas y por lo tanto, permiten a uno a estudiar el proceso de maduración de las neuronas granulares nacidos. Cultivos de cortes permiten la manipulación farmacológica eficaz de los cortes de hipocampo excluyendo variables complejas tales como las incertidumbres relacionadas con la localización anatómica profunda del hipocampo, así como la barrera hematoencefálica. Por estas razones, hemos tratado de optimizar cultivos de cortes organotípicos específicamente para la investigación neurogénesis postnatal.
Introduction
Adult neurogenesis in the mammalian hippocampus represents a remarkable example of the brain’s innate capacity for adaptability and plasticity. Dentate granule cells (DGCs) are generated from a renewable pool of neural progenitor cells in the hippocampal dentate gyrus, which is one of the two presently well-characterized neurogenic regions in the mammalian brain, and is thought to be particularly important for learning and memory. The hippocampus is part of the limbic system and has a deep location within the mammalian brain, which makes it a difficult target for precise pharmacological manipulation. Additionally, aberrant neurogenesis has been implicated in conditions, such as epilepsy, schizophrenia, and Alzheimer’s disease, which has prompted interest in understanding the influence of various pharmacological agents during the maturation and survival of newborn neurons. The distinction between postnatal and adult neurogenesis is blurred and previous studies have shown that many features of in vivo neuronal development in the early postnatal period and adulthood are similar25. Here we emphasize postnatal neurogenesis and suggest possible applications to adult neurogenesis.
Organotypic slice cultures provide an efficient in vitro method for studying various physiological properties of the mammalian hippocampus. The value of slice cultures prepared from rodent brains can be summarized in three main qualities: 1) the protocol is straightforward and requires readily available materials; 2) slice cultures allow for pharmacological studies that eliminate complex variables such as the deep anatomic location of the hippocampus and circumvents the blood brain barrier1; and 3) the well characterized structure of the hippocampus and tri-synaptic circuit is preserved2. Previous investigators have used the organotypic hippocampal culture to study synaptic development and physiology3,4, gliogenesis5-7, ischemic brain damage8,9, neuroprotection and neurorepair10-12 as well as epilepsy13-15.The slice cultures could also provide a useful model system allowing for the monitoring of cell development in conjunction with labeling of cells with green fluorescent protein (GFP) or other vital markers.
Slice cultures have also been previously employed to study postnatal hippocampal neurogenesis16-19, but one important factor in the majority of these studies is the well-characterized degeneration that results from explanting tissue from adult animals after approximately 2 weeks in vitro20,21. For this reason, slice cultures are typically prepared from early post-natal (P5-P10) mice or rat pups, which utilizes the improved viability of early postnatal brain tissue for culturing22. While previous studies have shown that the early postnatal and adult hippocampus differ with regards to synaptic physiology and the expression of specific neuronal subtypes23,24, there is substantial conservation of the choreographed developmental program that newborn dentate granule cells proceed through during maturation25. Additionally, recent studies have suggested that the physiological characteristics of newborn DGCs in culture are very similar to immature neurons in the acute hippocampal slice preparation16.
Protocol
Representative Results
Discussion
Después de CldU (o BrdU) administración, la línea de tiempo de aplicación de agentes farmacológicos puede ser elegido para dirigir PED recién nacido durante particulares ventanas de desarrollo. Por ejemplo, un agente hipotético se puede aplicar durante la segunda semana post-inyección CldU, que se propone para coincidir con la edad de las neuronas inmaduras que se encuentran en una etapa de desarrollo en que se GABA despolarizante. Futuros estudios que utilizan este protocolo podrían adaptar el agente farmacol?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by a research grant MOP 119271 to JMW by the Canadian Institute of Health Research. The authors would like to thank Ms. Yao Fang Tan for her outstanding technical assistance.
Materials
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| 5-chloro-2'-deoxyuridine (CldU) | MP Biomedicals | 105478 | Hazardous, Carcinogenic |
| Cell culture inserts, 30mm diameter, 0.4µm pore size | Thermo scientific | 140660 | Nuclon delta coating on these inserts provides better tissue adhesion and improves slice quality. |
| Conical Centrifuge tubes (sterile) | Fisher Scientific | 14-432-22 | |
| Dissector scissors (angled to side) | Fine Science Tools | 14082-09 | |
| Minimum essential medium (MEM) | Gibco | 11095; liquid | Store at 4°C |
| Eclipse Ni-U fluorescent microscope | Nikon | ||
| Glue for tissue | Krazy Glue | KG585 | Use minimum amount of glue to achieve adhesion as any tissue exposed to glue will be unusable for IHC. |
| Hank’s Balanced Salt Solution (HBSS) (500 mL) | Gibco | 14025-092 | Store at 4°C |
| Horse Serum Heat Inactivated (500 mL) | Gibco | 16050-122 | Make 50 mL aliquots and store at -20°C |
| Kimwipes | Kimberly-Clarke | TW 31KYPBX | |
| Modified glass pipettes (bottom of Pasteur pipette removed and edge smoothed with Bunsen flame) | |||
| Petri Dish (100mm x 15mm) and (60mm x 15mm) | Fisher Brand | FB0875712 and FB0875713A | |
| Scalpel blades #11 | Fine Science Tools | 10011-00 | |
| Scalpel handle #3 | Fine Science Tools | 10003-12 | |
| Serological Pipettes | Sorfa Medical Plastic Co. | P8050 | |
| Standard Pattern forceps | Fine Science Tools | 11000-12 | |
| Sterile vacuum filter | Thermo-Scientific | 565-0020 | |
| Surgical Scissors | Fine Science Tools | 14054-13 | |
| Syringe driven filter unit | Millipore-Millex | SLGP033RS | |
| Tissue chopper with moveable stage | Stoelting | 51425 | |
| Fine tip paintbrush |
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