Unrestricted.2016-11-142011-02-192016-11-142003-12http://hdl.handle.net/2346/21802Apoptosis, or programmed cell death (PCD), is a normal physiological event whereby unnecessary cells are eliminated from the body. Caspase 3 has been extensively studied as a central mediator of apoptosis. Previous research in our lab eluded to a nonapoptotic function, and possibly even a developmental role for active caspase 3 in the external granule layer (EGL) of the rat cerebellum. In the developing rat cerebellum, the folia (or lobules) express different rates of maturation for the formation of the Purkinje cells (Altman, 1985) and for the internal granule cell layer (IGL) (Altman, 1972). Although active caspase 3 has been associated with various developmental events, to date the expression of active caspase 3 in relation to cerebellar folial development has not been examined. The expression of active caspase 3 in relation to Bergmann glial cells also has never been examined. The purpose of this study is twofold. The first hypothesis is that the expression of active caspase 3-positive cells in the vicinity of the Purkinje cell layer (PCL) is related to the development of cerebellar folia, as well as being developmentally related with respect to age and region of the cerebellum. The second hypothesis is that active caspase 3 has a nonapoptotic role in the cells surrounding the Purkinje cells (PCs) in the developing rat cerebellum. The present study incorporates immunohistochemistry, using a confocal laser scanning microscope to determine the abundance of caspase 3-positive cells within each cerebellar folia of rats at postnatal days 9, 21, and 30. It also employs TUNEL and Annexin V to determine apoptosis, or lack thereof. We have observed the presence of active caspase 3-positive cells in close proximity to the Purkinje cells. Caspase 3-positive cells are minimal at 9 days of age. At 21 days and 30 days, caspase 3-positive cells appear to be prevalent in all lobules. The caspase 3-positive cells did not colocalize with TUNEL or Annexin V. These findings suggest that the expression of active caspase 3-positive cells in the vicinity of the Purkinje cell layer correlates with development in the rat cerebellum with respect to age and region, but not with folial development. They also suggest that active caspase 3 has a nonapoptotic role in the cells that are in the proximity of the Purkinje cells in the developing rat cerebellum. These cell were identified in coincidental studies in our lab as being Bergmann glial cells. The nature and functions of nonapoptotic caspase 3 in Bergmann glial cells are still being investigated by our lab, although it is believed to play a role in the differentiation of the cells. The significance of this study is that it is the first that we are aware of to examine active caspase 3 in the Bergmann glial cells. It is also the first that we are aware of to examine a nonapoptotic role for caspase 3 in the developing cerebellum.application/pdfengRats -- ResearchApoptosis -- PhysiologyBrain pathologyNeurons -- PhysiologyThesis