Nitroreductase/Metronidazole-Mediated Ablation and a MATLAB Platform (RpEGEN) for Studying Regeneration of the Zebrafish Retinal Pigment Epithelium

Rutin hydrate relieves neuroinflammation in zebrafish models: Involvement of NF-κB pathway as a central network

Neuroinflammation is prevalent in multiple brain diseases and may also lead to dementia, cognitive impairment, and impaired spatial memory function associated with neurodegenerative diseases. A neuroprotective and antioxidant flavonoid, rutin hydrate (RH), was evaluated for the anti-neuroinflammatory activity mediated by copper sulfate (CuSO4) solution and lipopolysaccharide (LPS) in zebrafish. The results showed that 100 mg/L RH significantly reduced the ratio of neutrophil mobility in caudal hematopoietic tissue (CHT) region caused by CuSO4 and the number of neutrophils co-localized with facial peripheral nerves. In the LPS model, RH co-injection significantly diminished neutrophil and macrophage migration. Therefore, RH exhibited a significant rescue effect on both models. In addition, RH treatment remarkably reduced the effects of neuroinflammation on the locomotor ability, expression levels of genes associated with behavioral disorders, and acetylcholinesterase (AChE) activity. Furthermore, network pharmacology techniques were employed to investigate the potential mechanisms, and the associated genes and enzyme activities were validated in order to elucidate the underlying mechanisms. Network pharmacological analysis and zebrafish model indicated that RH regulated the expressions of NF-κB pathway-related targets (Toll-like receptor 9 (tlr9), nuclear factor kappa B subunit 1 (nfkb1), RELA proto-oncogene (RelA), nitric oxide synthase 2a, inducible (nos2a), tumour necrosis factor alpha-like (tnfα), interleukin 6 (il6), interleukin 1β (il1β), chemokine 8 (cxcl8), and macrophage migration inhibitory factor (mif)) as well as six key factors (arachidonic acid 4 alpha-lipoxygenase (alox4a), arachidonate 5-lipoxygenase a (alox5), prion protein a (prnpa), integrin, beta 2 (itgb2), catalase (CAT), and alkaline phosphatase (ALP) enzymes). Through this study, a thorough understanding of the mechanism underlying the therapeutic effects of RH in neuroinflammation has been achieved, thereby establishing a solid foundation for further research on the potential therapeutic applications of RH in neuroinflammatory disorders.

Ronidazole Is a Superior Prodrug to Metronidazole for Nitroreductase-Mediated Hepatocytes Ablation in Zebrafish Larvae

The liver plays a very important role in physiological processes of the human body. Liver regeneration has developed into an important area of study in liver disease. The Mtz (metronidazole)/NTR (nitroreductase)-mediated cell ablation system has been widely used to study the processes and mechanisms of liver injury and regeneration. However, high concentrations and toxic side effects of Mtz severely limit the application of the Mtz/NTR system. Therefore, screening new analogs to replace Mtz has become an important means to optimize the NTR ablation system. In this study, we screened five Mtz analogs including furazolidone, ronidazole, ornidazole, nitromide, and tinidazole. We compared their toxicity on the transgenic fish line Tg(fabp10a: mCherry-NTR) and their specific ablation ability on liver cells. The results showed that Ronidazole at a lower concentration (2 mM) had the same ability to ablate liver cells comparable with that of Mtz (10 mM), almost without toxic side effects on juvenile fish. Further study found that zebrafish hepatocyte injury caused by the Ronidazole/NTR system achieved the same liver regenerative effect as the Mtz/NTR system. The above results show that Ronidazole can replace Mtz with NTR to achieve superior damage and ablation effects in zebrafish liver.