| dc.contributor.author | Rideout, Hardy Joseph. | en_US |
| dc.date.accessioned | 2014-10-21T12:33:56Z | |
| dc.date.available | 1999 | |
| dc.date.issued | 1999 | en_US |
| dc.identifier.other | AAINQ49286 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55668 | |
| dc.description | This thesis describes the development of a novel in vitro Schwann cell isolation method that results in the establishment of two populations of Schwann cells depending upon the age of the rat used. Schwann cells from PD15 rat sciatic nerve proliferate in vitro without the need for additional growth factor supplementation, whereas PD2 Schwann cells require further support to induce proliferation. These two populations were used to investigate the direct effects of high glucose on Schwann cell survival. | en_US |
| dc.description | It was shown that exposure to high glucose leads to a dose- and time-dependent decrease in survival in both populations of Schwann cells. Significant cell death was observed at 2 hr following exposure to high glucose by counts of intact nuclei. Using two independent in situ markers of the nuclear changes associated with the final degradative phase of apoptosis, chromatin condensation and intemucleosomal DNA fragmentation, a significant proportion of this cell loss was determined to be due to apoptosis. Dual staining revealed that while internucleosomal DNA fragmentation was not present at 2 hr following exposure to high glucose; significant changes in nuclear structure were evident, including the presence of nuclear blebs, which have been observed in other models of apoptotic cell death. In addition, the anti-apoptotic agents IGF-I, NAC, and DMD each prevented cell loss observed at 2 hr following exposure to 40 mM glucose, suggesting that the death observed at this time point was indeed apoptotic. | en_US |
| dc.description | A central convergence point in many forms of apoptosis is the opening of a mitochondrial megapore, known as the permeability transition pore (PTP), coupled to the collapse of the voltage potential across the inner mitochondrial membrane (DeltaPsiM). It was shown here that exposure to high glucose induced a time-dependent decrease in DeltaPsiM that was preventable by anti-apoptotic agents that improve Schwann cell survival. It was further shown that the PTP was involved in high glucose induced apoptosis. An agent that maintains PTP closure, cyclosporin A, maintained DeltaPsi M and prevented the death of Schwann cells in high glucose media. Using confocal imaging it was determined that the localization of hexokinase at the PTP was dependent upon DeltaPsiM and the conformation of the PTP, further implicating mitochondria in high glucose induced apoptosis. Western blot analysis of sub-cellular fractions confirmed the findings of others showing that the pro- apoptotic protein, Bax, was increased in enriched mitochondrial fractions of Schwann cells exposed to high glucose. | en_US |
| dc.description | Taken together, these findings demonstrate for the first time that high glucose is toxic to Schwann cells in vitro, and that the cells die via apoptosis. It was further shown that this process involved a disruption of mitochondrial function at the PTP through a re-distribution of the proteins Bax and hexokinase. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1999. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Neuroscience. | en_US |
| dc.subject | Biology, Cell. | en_US |
| dc.title | Schwann cell apoptosis in an in vitro model of diabetic neuropathy: Mitochondrial dysfunction and the permeability transition pore. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
