Zebrafish LTB4-induced Inflammation Models

Leukotriene B4 (LTB4) is an eicosanoid released by leukocytes that acts as a pro-inflammatory mediator and enhances leukocyte accumulation at sites of inflammation. LTB4 has well-established biological roles, including promoting leukocyte chemotaxis and regulating pro-inflammatory cytokines by binding to G protein-coupled receptors called Ltb4r1 or Ltb4r2. Ltb4r1 (also known as Blt1) is a high-affinity receptor for LTB4 and is expressed on a variety of inflammatory and immune cells, including granulocytes, eosinophils, macrophages, differentiated Th1, Th2 and Th17 cells, effector CD8 T cells cells, dendritic cells and osteoclasts.

Currently, zebrafish has become a versatile animal model in various fields of biomedical research, including immunology, toxicology, cancer, and behavioral biology. Notably, zebrafish neutrophils develop at 18 hpf and mature between 24 and 48 hpf, similar to human neutrophils in dividing nucleus, granule, and myeloperoxidase expression. In addition, zebrafish display conserved key parts of the adaptive immune system, including thymus development, thymocyte development, and T- and B-cell function. The adaptive immune system matures after 3 to 4 weeks, which means that the innate immune system can be studied separately in the early embryonic and larval stages. Since the immune system of zebrafish is highly similar to that of humans, there have been many successful attempts to use zebrafish to mimic human inflammatory diseases in recent years. Furthermore, LTB4 has been shown to attract both neutrophils and macrophages in zebrafish.

Fig 1. Disruption of Lta4h signaling abrogates macrophage aggregation.

Our Zebrafish LTB4-induced Inflammation Models

Creative Biogene inject LTB4 into the ear sac of 3 dpf zebrafish larvae to induce inflammation, and recruitment of neutrophils to the ear can be observed after injection. We inject LTB4 into the hindbrain at 30 hpf to induce inflammation, and recruitment of macrophage to the ear was observed after injection.Creative Biogene injected LTB4 into the ear sac of 3 dpf zebrafish larvae to induce inflammation, and recruitment of neutrophils to the ear was observed after injection. We inject LTB4 into the hindbrain at 30 hpf to induce inflammation and observed recruitment of macrophages to the ear after injection.

In these models we can quantify LTB4-induced neutrophils by counting cells in the pelvic fins, measure systemic LTB4 concentrations in zebrafish by ELISA, determine the expression of genes involved in inflammatory pathways by qPCR, and analyze involvement by microarray experiments Genes of the immune system, genes encoding transcription factors, and genes involved in metabolism. In addition, our zebrafish confinement array trapping microfluidic device can be used to rapidly localize zebrafish embryos and larvae to form predictable arrays suitable for automated imaging. The device is not only capable of screening compounds with therapeutic effects on LTB4-induced inflammation, but may also be used for other inflammatory assays, such as tail injury.

Our Advantages

• Transgenic models available
• Provides automated high-throughput drug screening
• Easily monitor the progression of the disease

Creative Biogene not only provides models of LTB4-induced inflammation, but can also design experiments and provide experimental results according to your research goals. If you would like to learn more about zebrafish models, please feel free to contact us.

References

1. Xie Y, Meijer AH, Schaaf MJM. Modeling Inflammation in Zebrafish for the Development of Anti-inflammatory Drugs. Front Cell Dev Biol. 2021, 8:620984.
2. Vincent WJB, et al. Neutrophil derived LTB4 induces macrophage aggregation in response to encapsulated Streptococcus iniae infection. PLoS One. 2017, 12(6):e0179574.
3. Li P, et al. LTB4 promotes insulin resistance in obese mice by acting on macrophages, hepatocytes and myocytes. Nat Med. 2015, 21(3):239-247.

For research use only. Not intended for any clinical use.