The zebrafish has become a commonly used vertebrate model for toxicity assessment, of particular relevance to the study of toxic effects on the visual system because of the structural similarities shared by zebrafish and human retinae. In this article we present a colour preference-based technique that, by assessing the functionality of photoreceptors, can be used to evaluate the effects of toxicity on behaviour. A digital camera was used to record the locomotor behaviour of individual zebrafish swimming in a water tank consisting of two compartments separated by an opaque perforated wall through which the fish could pass. The colour of the lighting in each compartment could be altered independently (producing distinct but connected environments of white, red or blue) to allow association of the zebrafish's swimming behaviour with its colour preference. The functionality of the photoreceptors was evaluated based on the ability of the zebrafish to sense the different colours and to swim between the compartments. The zebrafish tracking was carried out using our algorithm developed with MATLAB. We found that zebrafish preferred blue illumination to white, and white illumination to red. Acute treatment with acrylamide (2mM for 36 hours) resulted in a marked reduction in locomotion and a concomitant loss of colour-preferential swimming behaviour. Histopathological examination of acrylamide-treated zebrafish eyes showed that acrylamide exposure had caused retinal damage. The colour preference tracking techniquehas applications in the assessment of neurodegenerative disorders, as a method for preclinical appraisal of drug efficacy and for behavioural evaluation of toxicity.

The use of zebrafish larvae has aroused wide interest in the medical field for its potential role in the development of new therapies. The larvae grow extremely quickly and the embryos are nearly transparent which allows easy examination of its internal structures using fluorescent imaging techniques. Medical treatment of zebrafish larvae can directly influence its swimming behaviours. These behaviour changes are related to functional changes of central nervous system and transformations of the zebrafish body such as muscle mechanical power and force variation, which cannot be measured directly by pure experiment observation. To quantify the influence of drugs on zebrafish larvae swimming behaviours and energetics, we have developed a novel methodology to exploit intravital changes based on observed zebrafish locomotion. Specifically, by using an in-house MATLAB code to process the recorded live zebrafish swimming video, the kinematic locomotion equation of a 3D zebrafish larvae was obtained, and a customised Computational Fluid Dynamics tool was used to solve the fluid flow around the fish model which was geometrically the same as experimentally tested zebrafish. The developed methodology was firstly verified against experiment, and further applied to quantify the fish internal body force, torque and power consumption associated with a group of normal zebrafish larvae vs. those immersed in acetic acid and two neuroactive drugs. As indicated by our results, zebrafish larvae immersed in 0.01% acetic acid display approximately 30% higher hydrodynamic power and 10% higher cost of transport than control group. In addition, 500 μM diphenylhydantoin significantly decreases the locomotion activity for approximately 50% lower hydrodynamic power, whereas 100 mg/L yohimbine has not caused any significant influences on 5 dpf zebrafish larvae locomotion. The approach has potential to evaluate the influence of drugs on the aquatic animal’s behaviour changes and thus support the development of new analgesic and neuroactive drugs.

Long-term alcohol intake from food can lead to numerous mental disorders in humans, and cause serious problems for governments and families worldwide. However, currently, it is unclear how alcohol affects the hypothalamic–pituitary–adrenal (HPA) axis. In the present study, using zebrafish larvae exposed to 1% ethanol, we made Zebrafish behavioural analysis, samples were collected for the enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR) experiments,and made statistical analyses at last. we found that ethanol decreases the locomotor activity of zebrafish larvae,showed a more intense reaction to external stimuli,increases the secretion of HPA axis hormones in zebrafish larvae,influences the secretion of neurotransmitters,alters key gene expression during neurotransmitter metabolism. Ethanol exposure reduced zebrafish locomotor activity, increased their HPA axis activity, and led to significant changes in the secretion of dopamine and serotonin. These findings provide us with a new understanding of the effects of ethanol on the HPA axis.

No abstract

No abstract

Repeated High-G shocks and whole-body vibration (WBV) can increase the risk of fatigue and injuries in the lumbar region of the spine for crew and passengers on High-speed craft (HSC). Existing reviews have suggested the beneficial effects of abdominal belts regarding lumbar torso stabilization and spinal unloading. The paper provides a novel 3-D seated human model with a virtual belt to simulate the belt effects for occupants on HSC. The model is built with AnyBody, a commercial software for musculoskeletal simulation based on the inverse dynamics method. The belt behaves like an additional force exerted in the lumbar region, and the force magnitude has been optimized to avoid discomfort during long journeys. The belt effects have been studied with different levels of wave shock, anthropometries, and belt design parameters such as belt width and position. Wave shocks exerted on seat surface are considered to include both vertical and off-vertical (horizontal) acceleration and expressed with a half-sine pulse. The belt effects are evaluated with intra-abdominal pressure (IAP), transversus muscle activities, and spinal compressive force. The results have shown a combined increase of IAP (137% maximum) and a decrease of spinal compressive force at the L4/L5 joint (15.5% maximum) once the belt is applied under various circumstances. Transverse abdominis activity is also reduced with belt application. The belt performs best when it covers the entire lumbar region. Reduction of belt width might lead to increased muscle activity for the muscle that isn't covered by the belt, inducing over-recruited muscle. For the same belt width, belt position variations are irrelevant to the belt performance. It has been validated that the abdominal belt can significantly assist abdominal muscles and maintain a solid core during intense WBV generated in different sea states, reducing fatigue and the risk of injury to the lumbar. Therefore, the model can be a preliminary guide for designing the abdominal belt.

In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage.