Purchase this article with an account.
Jennifer Thomas, Xixia Luo, Ryan Thummel; Reactive Gliosis in Adult Zebrafish Retinal Regeneration. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1162.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Müller glial cells in the mammalian retina respond to injury with reactive gliosis, which is characterized by Müller glial cell hypertrophy, upregulation of filamentous proteins, and release of neurotrophic growth factors. While these responses are initially neuroprotective to the surrounding neurons, persistent disregulation of Müller glial function ultimately leads to retinal cell death. Müller glial cells in the zebrafish retina initially respond to injury in a similar manner, however, zebrafish Müller glial cells then downregulate filamentous proteins and re-enter the cell cycle to create clusters of progenitor cells. These progenitors continue to proliferate as they migrate to the site of damage, where they ultimately differentiate into new retinal neurons. As part of our larger goal to reveal the signals that regulate reactive gliosis and regeneration, this study will establish and characterize a model of reactive gliosis in the zebrafish retina that mimics the response of the mammalian retina to injury.
Adult albino zebrafish were exposed to constant intense light, which destroys photoreceptors and induces a regenerative response from the underlying Müller glial cells. Intravitreal injections of 5-Fluorouracil (5-FU) were used to inhibit proliferation during the S phase of the cell cycle. Retinal tissue was harvested and analyzed at various times following constant-intense light damage for proliferation and specific markers of reactive gliosis.
Following 18 hours of constant-intense light damage (hLT), an upregulation of filamentous proteins was observed in both 5-FU and saline-injected eyes. At 24 to 36 hLt, a downregulation of filamentous proteins was observed in saline-injected eyes that correlated with PCNA upregulation. However, in 5-FU injected eyes, a persistent upregulation of filamentous proteins along with significantly fewer proliferating Müller glial cells was observed. Remarkably, this response initially protected the photoreceptors from the light damage. However, similar to the mammalian response, persistent reactive gliosis in the zebrafish led to the gradual loss of photoreceptor cells and an absence of retinal regeneration.
These data show that the reactive gliosis response observed in mammalian retina can be induced in the zebrafish, and that this response is directly linked to the ability of the Müller glial cell to re-enter the cell cycle.
This PDF is available to Subscribers Only