Explants prepared from 17- to 18-day fetal rat spinal cord were allowed to mature in culture; such preparations have been shown to differentiate and myelinate in vitro (61) and to be capable of complex bioelectric activity (14-16). At 23, 35, or 76 days, the cultures were fixed (without removal from the coverslip) in buffered OsO(4), embedded in Epon, sectioned, and stained for light and electron microscopy. These mature explants generally are composed of several strata of neurons with an overlying zone of neuropil. The remarkable cytological similarity between in vivo and in vitro nervous tissues is established by the following observations. Cells and processes in the central culture mass are generally closely packed together with little intervening space. Neurons exhibit well developed Nissl bodies, elaborate Golgi regions, and subsurface cisternae. Axosomatic and axodendritic synapses, including synaptic junctions between axons and dendritic spines, are present. Typical synaptic vesicles and increased membrane densities are seen at the terminals. Variations in synaptic fine structure (Type 1 and Type 2 synapses of Gray) are visible. Some characteristics of the cultured spinal cord resemble infrequently observed specializations of in vivo central nervous tissue. Neuronal somas may display minute synapse-bearing projections. Occasionally, synaptic vesicles are grouped in a crystal-like array. A variety of glial cells, many apparently at intermediate stages of differentiation, are found throughout the otherwise mature explant. There is ultrastructural evidence of extensive glycogen deposits in some glial processes and scattered glycogen particles in neuronal terminals. This is the first description of the ultrastructure of cultured spinal cord. Where possible, correlation is made between the ultrastructural data and the known physiological properties of these cultures.
Abstract When strips of human skeletal muscle from biopsies of normal children and donors with Duchenne muscular dystrophy (DMD) are explanted in organotypic coculture with fetal mouse spinal cord, many regenerating muscle fibers develop, become innervated, and maintain a remarkable degree of mature structure and function for more than 3–6 months in vitro. Sequential light microscopy in correlation with electron‐microscopic and electrophysiologic analyses showed that despite cross‐species innervation, these human muscle fibers develop stable cross‐striations, peripherally positioned myonuclei, and mature, functional motor endplates. Of special interest is the onset of significant progressive abnormalities, e.g., unusual focal myofibrillar lesions, in substantial numbers of innervated mature DMD muscle fibers after 2–4 months in culture. The focal myofibrillar lesions were not detected in normal muscle fibers maintained as long as 6 months in coculture, nor are they comparable to the generalized loss of cross‐striations observed in muscle atrophy following in vitro denervation of mature DMD fibers.
Journal Article Ultrastructural Studies of the Dying-back Process: VI. Examination of Nerve Fibers Undergoing Giant Axonal Degeneration in Organotypic Culture Get access Bellina Veronesi, Ph.D., Bellina Veronesi, Ph.D. Institute of Neurotoxicology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neurology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Pathology (Neuropathology), Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York. Search for other works by this author on: Oxford Academic PubMed Google Scholar Edith R. Peterson, M.A., Edith R. Peterson, M.A. Institute of Neurotoxicology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neurology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Pathology (Neuropathology), Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York. Search for other works by this author on: Oxford Academic PubMed Google Scholar Murray B. Bornstein, M.D., Murray B. Bornstein, M.D. Institute of Neurotoxicology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neurology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Pathology (Neuropathology), Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York. Search for other works by this author on: Oxford Academic PubMed Google Scholar Peter S. Spencer, Ph.D., MRCpath Peter S. Spencer, Ph.D., MRCpath Institute of Neurotoxicology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neurology, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York.Department of Pathology (Neuropathology), Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York. Address correspondence and reprint requests to: Institute of Neurotoxicology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 1046. Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Neuropathology & Experimental Neurology, Volume 42, Issue 2, March 1983, Pages 153–165, https://doi.org/10.1097/00005072-198303000-00005 Published: 01 March 1983
Most neurons in organotypic cultures of dorsal root ganglia from 13-day-old fetal mice require high concentrations of nerve growth factor for survival during the first week after explanation. These nerve growth factor-enhanced sensory neurons mature and innervate the dorsal regions of attached spinal cord tissue even after the removal of exogenous growth factor after 4 days. In cultures exposed for 4 days to nerve growth factor and taxol (a plant alkaloid that promotes the assembly of microtubules) and returned to medium without growth factor, greater than 95 percent of the ganglionic neurons degenerated and the spinal cord tissues were reduced almost to monolayers. In contrast, when the recovery medium was supplemented with nerve growth factor, the ganglionic neurons and dorsal (but not ventral) cord tissue survived remarkably well. Dorsal cord neurons do not normally require an input from dorsal root ganglia for long-term maintenance in vitro, but during and after taxol exposure they become dependent for survival and recovery on the presence of neurite projections from nerve growth-factor-enhanced dorsal root ganglia.
