Nerve Fiber Diameter Measurements Using Hematoxylin and Eosin Staining and Brightfield Microscopy to Assess the Novel Method of Characterizing Peripheral Nerve Fiber Distributions by Group Delay

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral nerve fiber size distributions, and therefore does not show any detailed information regarding the nerve fibers within the nerve trunk. Being able to determine which nerve fibers are contributing to the evoked potential within a nerve trunk could provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system, such as chronic inflammatory demyelinating polyneuropathy or early diabetic peripheral neuropathy. In this study, three rat sciatic nerves are sectioned and stained with hematoxylin and eosin in order to measure the nerve fiber diameters within the nerve trunk. Stained samples are viewed using brightfield microscopy and images are analyzed using ImageJ. Histograms were created to show the frequency of various nerve fiber diameters. The nerve fiber diameters measured during this research are consistent with the range of previously published diameter values and will be used to support continuing research for a novel method to characterize peripheral nerve fiber size distributions using group delay. v ACKNOWLEDGMENTS I would like to thank my family, friends and colleagues who have offered their support and encouragement throughout my research and writing. I am extremely thankful for all the guidance and support of Dr. Robert Szlavik, who assisted me and believed in me throughout my entire project. His intelligence and communication helped me to further understand the topic at hand and be able to accomplish the great feat of completing a thesis. Dr. Szlavik has helped this experiment become a great learning experience. Thanks to all the faculty and staff at Cal Poly for all of your support and education. I would also like to thank Barry-Wehmiller Design Group, Inc. for hiring me and believing in me to finish my research. A special thanks to Yukiko Ikuta for pressuring me to finish my research and guiding me in the right direction. …