The hippocampal organotypic slice culture was used to study injury in the CNS. Studies characterized factors that influenced regenerative events in the hippocampal dentate gyrus, concomitant changes in glial cell populations, and examined the role of neuroglia in repair of damaged neural tissues Deafferentation of the hippocampus causes dentate granule cell axons, known as the mossy fibers, to initiate collateral neurite sprouting. Following axonal degeneration, mossy fibers form collaterals that invade the dental molecular layer, which contains denervated granule cell dendrites (Zimmer and Gahwiler, 1987) Factors influencing mossy fiber collateral sprouting were identified and found to include time in culture, positional origin of the slice culture along the septo-temporal axis of the hippocampus, and the presence of attached subicular-entorhinal cortical tissues. Additionally, differential damage to mossy fibers was not the basis for the differences in collateral sprouting along the septo-temporal axis Slice cultures were used to investigate glial cell responses to lesion-induced injury in the hippocampus. These experiments demonstrated a temporal correlation between reactive microglia, IL-1$\beta$, and astrocytic hypertrophy over a period of 10 days in vitro (DIV). Microglia were identified using lectin histochemistry, astrocytes and IL-1$\beta$ expressing cells were identified using immunocytochemical markers Reactive microglia steadily decreased as resting microglia increased over 10 DIV. IL-1$\beta$ (+) cells showed a similar pattern of temporal and regional distribution as reactive and resting microglial elements. The onset of astroglial hypertrophy in the dentate gyrus correlated closely with the timecourse of mossy fiber collateral sprouting described. Thus, in hippocampal slice cultures a transient and regional distribution of reactive and resting microglia, IL-1$\beta$ (+) cells and astrocytes occurs within the dentate gyrus during the first 10DIV Excessive numbers of reactive microglia have been correlated with the development and progression of neurodegenerative disease (Dickson, 1990). Experiments were conducted to identify activated and resting microglia, and their reactions to damage incurred during culture preparation. Spontaneous neurodegenerative sites were observed within the first 6DIV as well as within specific regions of the slice cultures. The addition of L-leucine methyl ester to slice cultures significantly reduced the frequency and distribution of neurodegeneration within the first 6DIV / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_23417 |
| Date | January 1996 |
| Contributors | Coltman, Bertram William, III (Author), Ide, Charles F (Thesis advisor) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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