The Effect of Ulinastatin to the Learning and Memory in Zebrafish

Fosab, but not fosaa, plays important role in learning and memory in fish-insights from zebrafish gene knockout study

Introduction: Learning and memory allow individuals to adapt to their environmental needs and survive. Fish have the ability to solve complex learning tasks, associative learning, and flexible spatial memory. The proto-oncogene fos (c-fos) has been reported to be involved in brain development, learning and memory in mammals. However, whether the c-fos plays a vital role in learning and memory in fish is unclear. Methods: Almost all fish have two paralogues of c-fos named fosaa and fosab. We used CRISPR/Cas9 technology to generate fosaa and fosab knockout zebrafish models. Results: In this study, we discovered the brain weight marked reduction in fosaa -/- and fosab -/- zebrafish compared with the wild-type (WT) (AB strain) zebrafish. In the T-maze behavioral assay, the fosab -/- zebrafish took significantly more than the average time to complete the assigned trial as the increase in the days compared to WT zebrafish, while the fosaa -/- zebrafish did not show a notable variance. The average time to complete the trial in fosab -/- zebrafish was significantly higher than in WT zebrafish. The relative mRNA expression level of c-jun in fosab -/- zebrafish was significantly higher than that in WT zebrafish, while the fosaa -/- zebrafish has no discernible trend. Additionally, the phylogenetic and multiple amino acid alignment results indicated that fish fosab has a higher identity with mammals Fos. Discussion: By integrating the above results, we found that fosab, but not fosaa, may possess a learning and memory function in fish. For the first time, we illustrated the role of fosaa and fosab in learning and memory via c-fos knockout in fish, which can provide new insights into environmental adaptation.

Benzophenone-3 causes oxidative stress in the brain and impairs aversive memory in adult zebrafish

Oxybenzone (BP-3) is an ultraviolet (UV) filter widely used in industries that is directly or indirectly released into the aquatic environment. However, little is known about its effects on brain performance. Here, we investigated whether BP-3 exposure affects the redox imbalance in zebrafish and how they respond to a task that requires memory of an aversive situation. Fish were exposed to BP-3 10 and 50 μg L-1 for 15 days and then tested using an associative learning protocol with electric shock as a stimulus. Brains were extracted for reactive oxygen species (ROS) measurement and qPCR analysis of antioxidant enzyme genes. ROS production increased for exposed animals, and catalase (cat) and superoxide dismutase 2 (sod 2) were upregulated. Furthermore, learning and memory were reduced in zebrafish exposed to BP-3. These results suggested that BP-3 may lead to a redox status imbalance, causing impaired cognition and reinforcing the need to replace the toxic UV filters with filters that minimize environmental effects.

Learning and memory formation in zebrafish: Protein dynamics and molecular tools

Research on learning and memory formation at the level of neural networks, as well as at the molecular level, is challenging due to the immense complexity of the brain. The zebrafish as a genetically tractable model organism can overcome many of the current challenges of studying molecular mechanisms of learning and memory formation. Zebrafish have a translucent, smaller and more accessible brain than that of mammals, allowing imaging of the entire brain during behavioral manipulations. Recent years have seen an extensive increase in published brain research describing the use of zebrafish for the study of learning and memory. Nevertheless, due to the complexity of the brain comprising many neural cell types that are difficult to isolate, it has been difficult to elucidate neural networks and molecular mechanisms involved in memory formation in an unbiased manner, even in zebrafish larvae. Therefore, data regarding the identity, location, and intensity of nascent proteins during memory formation is still sparse and our understanding of the molecular networks remains limited, indicating a need for new techniques. Here, we review recent progress in establishing learning paradigms for zebrafish and the development of methods to elucidate neural and molecular networks of learning. We describe various types of learning and highlight directions for future studies, focusing on molecular mechanisms of long-term memory formation and promising state-of-the-art techniques such as cell-type-specific metabolic labeling.

Protective Effect of Ulinastatin on Cognitive Function After Hypoxia

Ulinastatin (UTI) has neuroprotective properties. Neurologic insults, including hypoxia and use of anesthetic agents, cause postoperative cognitive dysfunction and alter gamma-aminobutyric acid (GABA) function. This study aimed to assess whether UTI could preserve learning and memory using a zebrafish hypoxic behavior model and biomarkers. Zebrafish (6-8 months of age and 2.5-3.5 cm long) were divided into eight groups as follows: phosphate-buffered saline (PBS) control, hypoxia + PBS, UTI (10,000, 50,000, and 100,000 units/kg), and hypoxia with UTI (10,000, 50,000, and 100,000 units/kg) groups. The endpoints of the T-maze experiment included total time, distance moved, and frequency in target or opposite compartment. We also measured the degree of brain infarction using 2,3,5‑triphenyltetrazolium chloride staining, assessed SA-β-galactosidase activity, and examined GABA_A receptor expression using real-time polymerase chain reaction. In a dose-dependent manner, UTI affected learning and memory in zebrafish. Despite hypoxia, 100,000 units/kg of UTI preserved preference (time and distance) for the target compartment. More than 50,000 units/kg of UTI also showed reduced hypoxia-induced brain infarction, decreased SA-β-galactosidase levels, and upregulated GABA_A receptors. This study demonstrated that the location of the GABA_A receptor is affected by hypoxia or UTI.

Zebrafish: A Pharmacological Model for Learning and Memory Research

Learning and memory are essential to organism survival and are conserved across various species, especially vertebrates. Cognitive studies involving learning and memory require using appropriate model organisms to translate relevant findings to humans. Zebrafish are becoming increasingly popular as one of the animal models for neurodegenerative diseases due to their low maintenance cost, prolific nature and amenability to genetic manipulation. More importantly, zebrafish exhibit a repertoire of neurobehaviors comparable to humans. In this review, we discuss the forms of learning and memory abilities in zebrafish and the tests used to evaluate the neurobehaviors in this species. In addition, the pharmacological studies that used zebrafish as models to screen for the effects of neuroprotective and neurotoxic compounds on cognitive performance will be summarized here. Lastly, we discuss the challenges and perspectives in establishing zebrafish as a robust model for cognitive research involving learning and memory. Zebrafish are becoming an indispensable model in learning and memory research for screening neuroprotective agents against cognitive impairment.

Somatostatin plus Ulinastatin in the Treatment of Severe Acute Pancreatitis and Its Effect on Serum Cytokine Levels

Objective

To investigate the effect of somatostatin combined with ulinastatin in the treatment of patients with severe acute pancreatitis and its effect on serum cytokine levels.

Methods

This study is a retrospective trial. One hundred patients with severe acute pancreatitis in our hospital between March 2020 and May 2021 were recruited and assigned into the control group (ulinastatin alone) and experimental group (somatostatin plus ulinastatin) according to different treatment methods, 50 cases each. The clinical efficacy and serum cytokine levels of the two groups were compared.

Results

Somatostatin plus ulinastatin was associated with a higher total effective rate versus ulinastatin alone (p < 0.05). After treatment, the experimental group observed significantly better interleukin-10 (IL-10), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) when compared with those in the control group (p < 0.05); somatostatin plus ulinastatin resulted in better serum amylase, blood calcium, blood urea nitrogen, blood sugar, and white blood cell count versus ulinastatin alone (p < 0.05).

Conclusion

Somatostatin plus ulinastatin is a viable alternative in the treatment of patients with severe acute pancreatitis, with a remarkable efficacy profile. It is worthy of clinical application.