Adrian Corbett (Committee Member), Debra Mayes (Committee Member), James Olson (Advisor)
Master of Science (MS)
Cerebral edema is a potentially fatal complication of diabetes. There is evidence for increased Reactive Oxidative Species (ROS) production during cerebral edema in diabetics. This can lead to oxidative stress, thought to contribute to the onset and progression of diabetes and can cause cell injury and cell death. ROS, in moderate amounts, are involved in physiological processes within the body that produce favorable cellular responses. Unfortunately, high levels of ROS can lead to cellular damage of lipids, membranes, proteins and DNA. Hyperglycemia can cause an increase in ROS production due to activation of NADPH oxidases. The purpose of this study is to determine if there is increased ROS production in swollen hyperglycemic cells thus leading to cell injury and also to determine the mechanism by which this increased ROS production occurs. C6 rat glioma cells were grown in normal glucose medium or were exposed to high glucose medium for 24 hours to simulate diabetic conditions. Cells were then perfused with isoosmotic and hypoosmotic PBS and ROS production was measured over a 30-minute experiment. There was no change in ROS production when cells grown in normal glucose (normoglycemic) medium were osmotically swollen. Cells grown in high glucose (hyperglycemic) medium had increased basal ROS production compared with cells grown in normal glucose medium. These cells further increased their ROS production when osmotically swollen. Blocking Nox2 and Nox4 enzyme activity decreased basal ROS production of cells grown either in normoglycemic or hyperglycemic conditions. Blocking Nox2 and Nox4 also decreased ROS production of hyperglycemic cells during hypoosmotic exposure. However, cells grown in normal glucose medium increased their production of ROS when osmotically swollen in the presence of Nox2 and Nox4 inhibitors. Western blot analysis was also done to determine expression of eNos in hyperglycemic cells as compared to normoglycemic cells. There was no difference in expression of eNos in hyperglycemic cells compared to normoglycemic cells.
Normoglycemic cells did not increase their ROS production in hypoosmotic conditions. Hyperglycemic cells had increased ROS production in isoosmotic conditions. This increase in ROS production is even greater when hyperglycemic cells are swollen. The increase in ROS production in hyperglycemic cells may be due to Nox, but it's not due to eNos. Swelling hyperglycemic cells in normoglycemic conditions causes mild cell injury. Hyperglycemia, a major risk factor of diabetes, causes cellular injury but even more so when there is cellular edema.
Department or Program
Department of Neuroscience, Cell Biology & Physiology
Year Degree Awarded
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