Here, we present a protocol to introduce a rat model of central fatigue using the modified multiple platform method (MMPM).
This method can help answer key questions in the model construction of central fatigue. For example, how to produce fatigue from both physical and psychological aspects and how to assess it. The main advantage of this technique is to compound mental factors with modified multiple platform method to better simulate the onset of central fatigue.
We first came up with the idea when we noticed the close association between intermittent sleep deprivation and central fatigue. We tried different hours and days of deprivation to induce central fatigue, and finally, found that 14 hours over 21 days was the right pattern. The model shows good validity in central fatigue, and it can be used in future studies to help review the underlying mechanism of the disease.
Begin by constructing an opaque plastic tank without a cover. Fix 15 circular platforms on the bottom of the tank, which orderly distribute in three rows and five columns. Leave enough space between each platform, roughly 13 centimeters between rows and 10 centimeters between columns.
Install a faucet in the water outlet on the lateral side of the tank. Finally, make an iron-wire netting cover for the tank, with a food box hanging on it. Begin by numbering the rats'tail roots with a marker.
Weigh the rats, excluding the extremely light or heavy ones, and divide the rest randomly into the model and control groups. Put the rats gently into the clean cages, and allow them to acclimate to the lab for at least three days. Provide sufficient water and food supply.
Begin by placing the tank on a flat service, then fill with seven centimeters of warm water, approximately one centimeter below the platform flat. Then put one day's worth of fodder and water into the food box, and hang it on the cover. Next, take the model group of rats out of the cage by the tail, and put them gently into the tank.
Launch all the rats in the water instead of the platforms to motivate their fear of water. Make sure that every rat gets a platform to stand on, while rats of the control group stay in their original cages with sufficient food and water. Next, cover the tank and monitor the rats.
After 14 hours, take the model rats out of the tank, and dry their hair with a dryer. Remark the rats'tails if it fades. Then, return the rat to the original cage with food and water.
Finally, flush out the tank and open the faucet to out-flow the sewage. Then, sterilize the tank with a 75%ethanol spray. Open-field test results indicate that, compared with the control group, there is a significant decrease in both rearing movement and average velocity of voluntary activity in model rats.
The elevated-plus maze test shows that 21 days of modeling decreased both entries and duration in the open arm significantly compared to the control group, while there was an increase in those in the close arm. The exhaustive swimming test indicated that the swimming duration of the model group is significantly shorter than the control group. Lastly, these results indicate that dopamine in the hypothalamus, as well as the ratio of dopamine to serotonin, significantly decreases in the model group compared to the control group, while serotonin content increases significantly.
After watching this video, you should have a good understanding of how to build a multiple platform tank and apply it in your central fatigue model. This is a non-invasive model, which is easy to master. While trying this model, it is critical to keep an eye on the rest, as they are quite aggressive in the first two weeks, and the injury may occur.
Though this model aims to provide insight into central fatigue, it can also be applied to other diseases by compounding factors or adjusting model durations, such as navigation fatigue and depression.
