Zebrafish and Inflammatory Bowel Disease

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Introduction:

Scientists have used inflammatory bowel disease (IBD) animal models for drug-induced, genetic engineering study for over 100 years. No other model like zebrafish precisely match the pathophysiology of IBD of humans. The immune system of zebrafish is very similar to that of humans. Zebrafish have served similar orthologs of human IBD susceptibility genes NOD1 and NOD2 and have orthologs of mammalian toll-like receptors (TLRs). In comparison to mice, genetic methods are easier to perform in zebrafish. Because of the similarity in gastrointestinal and immunological systems to those of mammals, the Danio rerio (zebrafish) is an excellent model for studying intestinal inflammation disease .we are going to explore about how we can do zebrafish IBD model and what are the assay performed.

What Is Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) used to describe disorders that involve chronic inflammation of digestive tract.

Types of IBD include:

Ulcerative colitis. This condition involves inflammation and sores (ulcers) along the superficial lining of your large intestine (colon) and rectum.
Crohn’s disease. This type of IBD is characterized by inflammation of the lining of your digestive tract, which often can involve the deeper layers of the digestive tract.

What Is Soyabean Meal?

Soybean meal is the primary protein source as a fish meal replacement, its low in price and high availability but it has been documented that ingestion of soybean meal triggers intestinal inflammation. Soybean seeds contain 40% of crude protein and about 20% of fat.

Antibodies Involved During Inflammation?

Pro-inflammatory cytokines generally regulate growth, cell activation, differentiation, and homing of the immune cells to the sites of infection with the aim to control and eradicate the intracellular pathogens, including viruses. Several cytokines play key roles in mediating acute inflammatory reactions, namely IL-1, TNF-a (involved in the process of pathological pain), IL-6, IL-11, IL-8 and other chemokines, G-CSF, and GM-CSF

How To Induce Inflammatory Bowel Disease On Zebrafish?

This diet ensured a high saponin content because we used soybean flour type I, a specifically defatted soybean flour with high protein content (protein ~52% (85+% dispersible and 1% fat)) and consequently an increased saponin concentration. The experimental diet (SBM) was composed of 50% w/w control diet and 50% w/w soybean flour, mixed with some water, then dried, and reduced in size to crumbs suitable for zebrafish consumption. Fish were fed with an automated system 3 times a day for 5 weeks.

Antibodies Involved In This Study?

Inflammatory cytokines (IL-1β, IL-6, IL-8, IL-10, TGFβ, TNF-α).

Histological & Biochemical Assay Performed?

Tartrate resistant acid phosphatase (TRAP):
Alkaline phosphatase (ALP)

Assays were performed separately after scale cut because zebrafish scale presents two different parts.

anterior part – bone tissue
Posterior part -epidermis.

So that it is possible to highlight the different bone marker expressions in the two parts of the scale. And also the epidermis has blood vessels that express high levels of ALP.

Molecular Assay Performed?

RT-PCR

Staining Performed?

Bone Matrix Vital Staining: To highlight the scale mineralized matrix resorption and its new deposition

Conclusion

SBM induced zebrafish stated that increase of pro, anti -inflammatory cytokine in intestinal mucosa has taken place from second week after third week except il-8 and TNFα other cytokine expression came to normal. In bone Alteration evaluation after three week, during acute intestinal inflammation .SBM altered TRAA bone markers states osteoclast activity Increased confirming the activation of bone anabolic function in this phase, as transitory osteoporosis take place in the border of the scale but not in centre because of progression of resorption Lacunae in scale centre due to persistent il-8 expression which is chronic inflammatory condition phase. In This study we came to know that TNFα elevated level access is a key factor to determine establishment of IBD, il-8 stimulates chronic inflammation state which supports a specific bone loss pattern in the central part of the scale. Also these in vivo models help us to understand the molecular and cellular mechanism that takes place in inflammation regulation and bone remodelling.

Zebrafish Studies:

Toxicology study in adult zebrafish
Modeling in zebrafish study
Toxicology study in larvae
Infection model in zebrafish
zebrafish fertility study
zebrafish neurology model