(full paper is archived in the Miller Library)
Title: Insulin-like growth factor I and fibroblast growth factor modulate neural progenitor cell proliferation in the adult zebrafish brain
Student Author(s): Webster, Brian
Faculty Advisor(s): Thompson, Stuart
Location: Final papers Biology 176H
Date: June 2002
Abstract: The brain of the zebrafish Danio rerio is known to contain undifferentiated neural stem cells which continue to divide throughout the life of the organism. Insulin-like growth factor I (IGF I), nerve growth factor (NGF) and fibroblast growth factor (bFGF) were investigated for their ability to modulate neural progenitor cell proliferation in organotypic slice cultures of the adult zebrafish brain. A monoclonal antibody to 5-bromo-2’-deoxyuridine (BrdU) permitted visualization of those cells that incorporated the nucleotide into DNA during S phase of mitosis. IGF I significantly stimulated neural progenitor cell proliferation across all brain regions investigated. bFGF significantly stimulated mitogenic activity in the dorsomedial optic tectum, torus longitudinalus, and thalamic nucleii, but inhibited cell proliferation in the periventricular hypothalamus. NGF did not stimulate cell proliferation in any of the brain regions tested. The anatomical locations of high proliferative cell density were investigated in vivo by exposing adult zebrafish to BrdU in the ambient water for 24 hours. High densities of dividing cells were found in the outer surface of the optic tectum, the periventricular gray zone of the optic tectum, the torus longitudinalus, the thalamic nucleii, the periventricular hypothalamus, the outer surface of the forebrain, and throughout the cerebellum. These findings shed light on the importance of cell division as a mechanism of central nervous system plasticity in adult teleost fishes and reveal the mitogenic effects of IGF I and bFGF in the growth of new neural tissue.