| This work involves the in vitro analysis of lens mitochondrial status and optical quality, involving an automated scanning laser system developed at the University of Waterloo and a novel analysis of metabolically active mitochondria in lens epithelial and superficial cortical fibre cells using a confocal laser scanning microscope and a mitochondria-specific dye, Rhodamine 123. The analysis of mitochondria showed that, in general, numerous mitochondria surround individual nuclei in lens epithelial cells, whereas longer and not as dense mitochondria are seen in lens superficial cortical fibre cells. Both are needed to support lens metabolic demand. However, mitochondria are localised to lens epithelial cells and the superficial zone of the cortical fibre cells in order to ensure lens transparency.; The results of a comparative morphologic study of mitochondria and sutures in lenses of nine fish species show that the distribution of mitochondria in fish lens epithelial and superficial cortical fibre cells is similar to that of mammalian lenses and that, contrary to previous reports, fish sutures consist of line, or in one case, a “Y” arrangement.; The results of dose response studies show that lens epithelial cells the mitochondria can recover after 24 hours following treatment with low doses and this measure correlates with recovery seen in lens optical properties. Moreover the results of both dose response studies and elevated glucose treatment indicate that the mitochondria of lens superficial cortical fibre cells are most sensitive to chemical treatments and elevated glucose.; In two studies involving models of free radical formation, a correlation between lens optical properties and mitochondrial integrity in dose response studies and elevated glucose treatment was seen while in a hyperbaric oxygen (HBO) study such a correlation was not evident. The difference may be explained by the change in lens proteins that takes place in the lens nucleus following HBO treatments, whereas in dose response studies change took place in the lens superficial cortex, the thin zone to which the distribution of mitochondria in lens superficial cortical fibre cells is restricted.; Overall, the results of this study indicate that there is a correlation between mitochondrial integrity and lens optical function, and that the recovery of mitochondria is seen in lens epithelial cells but not in superficial cortical fibre cells. Together, the analysis of mitochondrial integrity and lens optical function provides a model of biochemical and anatomical change involved both in lens response to chemical treatments and elevated glucose. |
