Submission Date

7-24-2015

Document Type

Paper- Restricted to Campus Access

Department

Biology

Faculty Mentor

Ellen Dawley

Student Contributor

Sarah Weggeman

Comments

Presented during the 17th Annual Summer Fellows Symposium, July 24, 2015 at Ursinus College.

Supported by a Howard Hughes Medical Institute (HHMI) grant.

Project Description

Microglia are the immune response cell of the Central Nervous System. They play a role in inflammation and provide restorative support to the CNS, including aiding in repair after a spinal cord injury or tail amputation. Microglia are derived from embryonic macrophages that move from the yolk to the CNS early in development. Their role in development is unclear but they are thought to direct invading vasculature, participate in synaptic pruning, and initiate and remove apoptotic cells. The two groups of amphibians, urodeles and anurans have different methods of tail regeneration and development, suggesting a possible difference in microglia morphology. While urodeles (Ambystoma mexicanum) have the ability to regenerate a tail throughout their lives, anurans (Xenopus laevis) only maintain that ability in the larval state (tadpole). In this study we attempted to find, map and describe the morphology of microglia in the Central Nervous System of Xenopus laevis and Ambystoma mexicanum (axolotl) using a few different experimental methods. Although paraffin embedding and immunohistological staining with tomato lectin were sufficient for finding microglia in Xenopus, the same did not work as well in axolotl embryos most likely because of the yolky tissue that hardens with paraffin embedding. Instead, plastic embedding was used to visualize the structure of Ambystoma embryo cross sections, but because of plastic’s impenetrable nature immunohistological staining with tomato lectin after sectioning was not possible. We are now in the process of finding a procedure that will allow us to whole-mount stain for microglia prior to plastic embedding in order to properly describe the distribution and morphology of microglia in the central nervous system of embryonic Ambystoma mexicanum and Xenopus laevis.

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