Owen Owens and Dr. Jeffery R. Barrow, Physiology and Developmental Biology
The Apical Ectodermal Ridge has been of great interest to those studying the development of the mammalian limb every since it was discovered that the AER is vital to the formation of correct limb patterning and general limb formation. The AER is a ridge of cells located on the tip of the mammalian limb where it signals inner cells, called mesenchyme during development. This study analyzed proliferation, or cell dividing, and apoptosis, or programmed cell death, of mesenchymal cells in the hope to support the hypothesis that the AER signals mesenchymal cells to migrate, not proliferate or undergo apoptosis. We hoped to observe negligible AER directed proliferation at +5, +7, +12, and +24 hours of development.
An overview of the weekly research process: (1) chicken eggs were allowed to develop in an incubator between seventy and eighty hours, (2) chicken embryos had a middle third of the central portion of AER removed by surgery, (3) limb was removed and prepared for sectioning, (4) limb was sectioned, cut into thin slices and put on a microscope slide, (5) limbs were stained for proliferation and apoptosis, (6) pictures of the limbs revealing potential proliferation and apoptosis were taken using a confocal microscope, and (7) data was statistically analyzed using Adobe Photoshop.
Though some data was achieved, research was hindered both by AER removal, cell sectioning, and most of all by the cell staining process. It is likely the cell staining process could be improved by using a process called antigen retrieval. The project aimed to publish having five limbs analyzed at each hour of development. However, only complete data for +5 and +7 hours was achieved, with one +12 hour. It is difficult to support our hypothesis without having full data for +12 and +24 hours. We need to show that proliferation and apoptosis is negligible throughout twenty fours hours of limb development. We are currently reviewing the data we have to see if we overlooked any usable data or if it is possible to increase the contrast of the pictures taken to better observe proliferation and apoptosis. From our present findings we still hope to support that proliferation and apoptosis is negligible.