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Differences in susceptibility to Mycobacterium chelonae in zebrafish (Danio rerio) lines commonly used in scientific
Andrew J Janik1, Christopher M Whipps1
1SUNY-ESF, State University of New York College of Environmental Science and Forestry, Environmental and Forest Biology, Syracuse, NY, USA.
Abstract:
Mycobacteriosis is one of the most common diseases encountered in laboratory zebrafish. These infections can present a problem to researchers using zebrafish because they may introduce unknown experimental variables. Whilst differences in severity of infections between species of Mycobacterium infecting zebrafish have been well documented, little is known about differences in susceptibility between zebrafish lines. Previous surveys have found higher prevalence in the TU zebrafish line relative to other lines, suggesting that there may be underlying genetic differences in susceptibility. This study investigates Mycobacterium chelonae H1E2-GFP infections in four different zebrafish lines commonly used in research (AB, 5D, casper and TU). Fish were exposed to a labelled (green-fluorescent protein (GFP)) strain of M. chelonae by intraperitoneal injection, and infection status was evaluated after 10 weeks. Visualization of GFP in euthanized fish and histology were used as endpoints. In GFP images, severity was assessed by image analysis, and in histological sections, counts of granulomas containing acid-fast bacteria were used. Results indicated differences in severity of infections between lines, but no significant differences in prevalence.
Insights
Zebrafish lines show varying susceptibility to Mycobacterium chelonae infections, impacting research. This study assessed infection severity and prevalence across four common zebrafish lines, revealing significant differences in disease outcome.
Area of Science:
- Aquatic animal models
- Infectious diseases
- Genetics
Background:
- Mycobacteriosis is a common disease in laboratory zebrafish, potentially introducing experimental variability.
- Differences in Mycobacterium infection severity are known, but zebrafish line susceptibility is poorly understood.
- Previous studies suggest genetic differences in susceptibility, with higher prevalence in the TU zebrafish line.
Purpose of the Study:
- To investigate Mycobacterium chelonae infections in four common zebrafish lines (AB, 5D, casper, TU).
- To evaluate differences in infection severity and prevalence among these zebrafish lines.
Main Methods:
- Zebrafish were intraperitoneally injected with a green-fluorescent protein (GFP)-labeled Mycobacterium chelonae strain.
- Infection status was assessed after 10 weeks using GFP visualization and histology.
- Severity was quantified by image analysis of GFP and granuloma counts in histological sections.
Main Results:
- Significant differences in infection severity were observed among the four zebrafish lines.
- No significant differences in infection prevalence were detected between the lines.
- The study identified varying susceptibility to Mycobacterium chelonae across different zebrafish genetic backgrounds.
Conclusions:
- Zebrafish line choice can influence Mycobacterium chelonae infection severity, a critical factor for experimental design.
- Understanding genetic susceptibility differences is crucial for standardizing zebrafish research and mitigating disease impact.
- Further research into the genetic basis of zebrafish susceptibility to mycobacteriosis is warranted.
