Zebrafish as a Model Organism for the Development of Drugs for Skin Cancer.

Skin cancer, which includes melanoma and squamous cell carcinoma, represents the most common type of cutaneous malignancy worldwide, and its incidence is expected to rise in the near future. This condition derives from acquired genetic dysregulation of signaling pathways involved in the proliferation and apoptosis of skin cells. The development of animal models has allowed a better understanding of these pathomechanisms, with the possibility of carrying out toxicological screening and drug development. In particular, the zebrafish (Danio rerio) has been established as one of the most important model organisms for cancer research. This model is particularly suitable for live cell imaging and high-throughput drug screening in a large-scale fashion. Thanks to the recent advances in genome editing, such as the clustered regularly-interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) methodologies, the mechanisms associated with cancer development and progression, as well as drug resistance can be investigated and comprehended. With these unique tools, the zebrafish represents a powerful platform for skin cancer research in the development of target therapies. Here, we will review the advantages of using the zebrafish model for drug discovery and toxicological and phenotypical screening. We will focus in detail on the most recent progress in the field of zebrafish model generation for the study of melanoma and squamous cell carcinoma (SCC), including cancer cell injection and transgenic animal development. Moreover, we will report the latest compounds and small molecules under investigation in melanoma zebrafish models.

Assessment of resveratrol on diabetes of zebrafish (Danio rerio).

Purpose: Zebrafish (Danio rerio) is an established model for studying various metabolic diseases. The aim of this study was to evaluate the effect of resveratrol as a natural polyphenol on reducing inflammation caused by hyperglycemia (diabetes) and its effect on digestive tissue as well as TNF-α, IFN-γ, and INL1ß genes in zebrafish. Methods: Within a 20-day period, the research was performed on 120 adult zebrafish, which were randomly classified into eight groups: two experimental treatments (induced glucose = +G) and (without glucose = -G), where each main group was as follows: CTRL = control and RSV resveratrol with doses 10, 20, and 30 µmol/L. At the end of the period, the blood glucose level was measured using glucose test strip, staining of intestinal tissue was done by hematoxylin and eosin (H&E), and expression of INF-γ, IL1-ß, and TNF-α genes extracted from the intestinal was measured via internal method RT-PCR. Data analysis in this study was performed using SPSS software version 21. One-way ANOVA and mean comparison of treatments by Duncan test were used for data analysis. All statistical analyses were performed at a significant level (P < 0.5) where the mean data were presented with standard deviation. Results: According to the results, the lowest blood sugar level at the end of the experiment belonged to the group (G-RSV20) where no significant difference was observed between treatments (P > 0.05). The highest expression of IL1-ß gene belonged to the (G + CTRL) group (P < 0.05), while the (G + RSV20) group showed the lowest expression of the INF-γ gene and had a significant difference with other groups (P < 0.05). In (G + RSV10) treatment, the lowest expression of TNF-α gene was observed and there was no significant difference with other treatments (P > 0.05). Resveratrol would improve the absorption of nutrients in the intestinal tissue by increasing the number of goblet cells as well as the width and height of the villi. Conclusion: Collectively, this study indicated that treatment with resveratrol could improve metabolic-mediated performances by reducing blood glucose, increasing food absorption in the intestine tissue, and reducing the expression of inflammatory genes in type 2 diabetic zebrafish model.

Correction to: Concurrent metformin and silibinin therapy in diabetes: assessments in zebrafish (Danio rerio) animal model.

[This corrects the article DOI: 10.1007/s40200-020-00637-7.].

Gut micobiota alteration by Lactobacillus rhamnosus reduces pro-inflammatory cytokines and glucose level in the adult model of Zebrafish.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is still a challenge for physicians to manage patient's circumstances. It is assumed that alterations in the normal flora may be involved in the pathogenesis of T2DM through inducing chronic inflammation. To investigate the effect of Lactobacillus rhamnosus as a common probiotic on T2DM, we induced an experimental model of T2DM in adult male Zebrafish by gradient hyper-glucose accumulation methodology. RESULTS: In this trial 3-month old male adult Zebrafish were divided in to four groups including two control groups and T2DM induced groups with or without probiotic treatment. After 5 days of acclimation, T2DM was induced by a gradient hyper-glucose accumulation methodology. Diabetic fishes had statistically abnormal blood glucose and pro-inflammatory cytokine levels compared to control group (p = 0.0001). These results suggest that probiotic intervention decreased the blood glucose level in the T2DM-P group by decreasing pro-inflammatory cytokines responsible for signaling in T2DM therapeutic modalities.

Concurrent metformin and silibinin therapy in diabetes: assessments in zebrafish (Danio rerio) animal model.

OBJECTIVE: In this study, zebrafish was used as a biological model to induce type 2 diabetes mellitus through glucose. Then, the effect of metformin and silibinin combination was examined on elevated blood glucose, intestinal tissues, liver enzymes, and TNF-α, IFN-γ, INL1ß genes as inflammation marker genes. METHODS: The liver enzymes (AST, ALT, and ALP) derived from fish viscera homogenate supernatants were assayed in an auto-analyzer. The expression of target genes was quantified on RNA extracted from the tails by an in-house RT-PCR method, with fine intestine tissue staining performed by hematoxylin and eosin protocol (H&E). RESULT: In the glucose-free treatments, metformin and silymarin decreased the levels of AST, ALT, and ALP enzymes in the blood. The combination of these two drugs had also a significant role in reducing glucose levels. The body weight increased significantly in the control group which was affected by glucose concentration, with the lowest body weight gain observed in the metformin group. The expression of INL-1ß gene was significantly enhanced in the control group and the highest IFN-γ expression was observed in both control groups with glucose (G + CTRL) and without glucose (G-CTRL) (p < 0.05). The lowest level of TNF-α gene expression was observed in the control + glucose group (G + CTRL) (p < 0.05). Diabetic state causes weak absorption whereby the fish body demands to increase absorption level by enhancing the amount of acidic goblet cells thereby acidifying the environment in the gastric tracts. CONCLUSION: Collectively, this study indicated that treatment with metformin and Silibinin could improve metabolic-mediated performances by reducing the expression of inflammatory genes and blood glucose, modulating liver enzymes, and ameliorating the intestinal inflammation in type 2 diabetic zebrafish model.