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Technical brief: Constant intense light exposure to lesion and initiate regeneration in normally pigmented zebrafish.

Rajaram K, Summerbell ER, Patton JG - Mol. Vis. (2014)

Bottom Line: However, this paradigm has only been applied to lesion zebrafish of the nonpigmented albino genetic background, which precludes the use of numerous transgenic reporter lines that are widely used to study regeneration.Photoreceptor loss triggers dedifferentiation and proliferation of Müller glia as well as progenitor cell proliferation.We also demonstrate that the timeline of regeneration response is comparable between the albino and the pigmented retinas.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN.

ABSTRACT
Zebrafish are capable of robust and spontaneous regeneration of injured retina. Constant intense light exposure to adult albino zebrafish specifically causes apoptosis of rod and cone photoreceptor cells and is an excellent model to study the molecular mechanisms underlying photoreceptor regeneration. However, this paradigm has only been applied to lesion zebrafish of the nonpigmented albino genetic background, which precludes the use of numerous transgenic reporter lines that are widely used to study regeneration. Here, we explored the effectiveness of constant intense light exposure in causing photoreceptor apoptosis and stimulating regeneration in normally pigmented zebrafish retinas. We show that constant intense light exposure causes widespread photoreceptor damage in the dorsal-central retinas of pigmented zebrafish. Photoreceptor loss triggers dedifferentiation and proliferation of Müller glia as well as progenitor cell proliferation. We also demonstrate that the timeline of regeneration response is comparable between the albino and the pigmented retinas.

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Related in: MedlinePlus

Effects of constant intense light exposure on cone cells of pigmented AB zebrafish. Retinas were collected from zebrafish before (0 h) and after the indicated length of light exposure. Retinas were processed for immunohistochemistry and stained with zpr1 antibody (red). Nuclei were counter-stained with TOPRO (blue). Dorsal retinas are shown. The arrowheads at 0 h indicate the ordered arrangement of the double cones; the bracket indicates ONL. White arrows show condensed zpr+ cells at 72 h of intense light. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar is 50 µm.
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f1: Effects of constant intense light exposure on cone cells of pigmented AB zebrafish. Retinas were collected from zebrafish before (0 h) and after the indicated length of light exposure. Retinas were processed for immunohistochemistry and stained with zpr1 antibody (red). Nuclei were counter-stained with TOPRO (blue). Dorsal retinas are shown. The arrowheads at 0 h indicate the ordered arrangement of the double cones; the bracket indicates ONL. White arrows show condensed zpr+ cells at 72 h of intense light. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar is 50 µm.

Mentions: To assess the effects of constant intense light exposure on pigmented zebrafish retinas, we subjected normally pigmented adult wild-type zebrafish (AB background) to constant intense light. Following a 2-week dark-adaptation period, AB fish were exposed to intense light for varying periods of time, after which retinas were dissected and probed using the Zpr1 antibody that recognizes red-green double cones. At the 0 h time point, before intense light exposure, we detected an ordered arrangement of zpr1+ double cones in the ONL with outer segments (OS) projecting beyond the ONL (Figure 1; arrowheads). However, by 24 h of intense light exposure, we detected disorganization and hypertrophy of the zpr1+ double cones in addition to thinning of the ONL across the central-dorsal retina (compare brackets in 0-h and 24-h panels), with sporadic damage in the ventral retina (data not shown). By 48 h of intense light exposure, the cone photoreceptor OS began to breakdown further and the cells appeared detached from the ONL. By 72 h, the ONL was thinner and the cone cells lost their projections entirely and appeared clumped or condensed (arrows).


Technical brief: Constant intense light exposure to lesion and initiate regeneration in normally pigmented zebrafish.

Rajaram K, Summerbell ER, Patton JG - Mol. Vis. (2014)

Effects of constant intense light exposure on cone cells of pigmented AB zebrafish. Retinas were collected from zebrafish before (0 h) and after the indicated length of light exposure. Retinas were processed for immunohistochemistry and stained with zpr1 antibody (red). Nuclei were counter-stained with TOPRO (blue). Dorsal retinas are shown. The arrowheads at 0 h indicate the ordered arrangement of the double cones; the bracket indicates ONL. White arrows show condensed zpr+ cells at 72 h of intense light. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar is 50 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4119235&req=5

f1: Effects of constant intense light exposure on cone cells of pigmented AB zebrafish. Retinas were collected from zebrafish before (0 h) and after the indicated length of light exposure. Retinas were processed for immunohistochemistry and stained with zpr1 antibody (red). Nuclei were counter-stained with TOPRO (blue). Dorsal retinas are shown. The arrowheads at 0 h indicate the ordered arrangement of the double cones; the bracket indicates ONL. White arrows show condensed zpr+ cells at 72 h of intense light. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar is 50 µm.
Mentions: To assess the effects of constant intense light exposure on pigmented zebrafish retinas, we subjected normally pigmented adult wild-type zebrafish (AB background) to constant intense light. Following a 2-week dark-adaptation period, AB fish were exposed to intense light for varying periods of time, after which retinas were dissected and probed using the Zpr1 antibody that recognizes red-green double cones. At the 0 h time point, before intense light exposure, we detected an ordered arrangement of zpr1+ double cones in the ONL with outer segments (OS) projecting beyond the ONL (Figure 1; arrowheads). However, by 24 h of intense light exposure, we detected disorganization and hypertrophy of the zpr1+ double cones in addition to thinning of the ONL across the central-dorsal retina (compare brackets in 0-h and 24-h panels), with sporadic damage in the ventral retina (data not shown). By 48 h of intense light exposure, the cone photoreceptor OS began to breakdown further and the cells appeared detached from the ONL. By 72 h, the ONL was thinner and the cone cells lost their projections entirely and appeared clumped or condensed (arrows).

Bottom Line: However, this paradigm has only been applied to lesion zebrafish of the nonpigmented albino genetic background, which precludes the use of numerous transgenic reporter lines that are widely used to study regeneration.Photoreceptor loss triggers dedifferentiation and proliferation of Müller glia as well as progenitor cell proliferation.We also demonstrate that the timeline of regeneration response is comparable between the albino and the pigmented retinas.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN.

ABSTRACT
Zebrafish are capable of robust and spontaneous regeneration of injured retina. Constant intense light exposure to adult albino zebrafish specifically causes apoptosis of rod and cone photoreceptor cells and is an excellent model to study the molecular mechanisms underlying photoreceptor regeneration. However, this paradigm has only been applied to lesion zebrafish of the nonpigmented albino genetic background, which precludes the use of numerous transgenic reporter lines that are widely used to study regeneration. Here, we explored the effectiveness of constant intense light exposure in causing photoreceptor apoptosis and stimulating regeneration in normally pigmented zebrafish retinas. We show that constant intense light exposure causes widespread photoreceptor damage in the dorsal-central retinas of pigmented zebrafish. Photoreceptor loss triggers dedifferentiation and proliferation of Müller glia as well as progenitor cell proliferation. We also demonstrate that the timeline of regeneration response is comparable between the albino and the pigmented retinas.

Show MeSH
Related in: MedlinePlus