Documentation

Introduction

The Pole Test is a behavioral test used to assess the locomotor function of rodents. It was introduced by Ogawa, Hirose, Ohara, Oro, and Watnabe (1985) to evaluate bradykinesia in rodent models of Parkinson’s and was later validated as a stroke model by Bouët (2007). 

During the Pole Test, a rodent is placed on the tip of a pole with its head pointed upward and is tasked to descend to the ground without pausing. The subject’s ability to descend to the floor by turning its body around without falling is used to assess its locomotor function or dysfunction after injury. Since some of the subjects may climb over the tip of the pole instead of descending by turning around, a piece of cardboard can be placed on the tip to prevent climbing. Apart from locomotor function assessment following injury, the Pole Test can also be used to determine motor performance improvements following drug treatments or motor experience after an injury. In addition, the test can also be used to assess long-term motor function in rodent models of stroke.

The Pole Test requires minimal equipment and provides direct results. Moreover, the test can be conducted in the subject’s home cage since it might prefer to descend to a familiar location. Other apparatuses used in assessing rodent motor function include the Balance Beam, the Parallel Bars, the Geotaxis Test, the Static Rods Test, and the Gait Test.

Apparatus and Equipment

The Pole Test apparatus consists of an acrylic pole that measures 8 mm in diameter and 50 cm in length. 

Training Protocol

Clean the pole after every trial. A tracking and recording system such as the Noldus Ethovision XT can be used to assist with observations.

Pole Test Task

Place the subject on the tip of the Pole Test apparatus with its head pointed upward. Allow the subject to descending to the floor by turning its head downward. If the subject pauses while descending, exclude the trial and conduct another one. If the subject falls while descending, assign the maximum duration of 120 seconds to the Turn and TD values. 

Literature Review

Evaluation of the Pole Test in rodent models of stroke 

Ruan and Yao (2020) reviewed several behavioral tests in rodent models of stroke in which the Pole Test was one of them. In studies conducted by Balkaya, Krober, Gertz, Peruzzaro, and Endres (2013) and Bouët et al. (2007), ischemic mice were assessed through the Pole Test apparatus and their latency to make the turn to descend (Tturn) and time taken to descend (TD) was assessed. Locomotor impairment was observed in the ischemic mice, which had increased Tturn and TD values compared to sham controls up to 11 days after injury. In another study conducted by Zhu et al. (2012), the effect of fluoxetine on pole test performance was evaluated. The results indicated that fluoxetine was able to improve performance in the Pole Test at 12 days and 20 days after stroke, which suggested that the Pole Test could reliably be used to assess the neuroprotective effect of novel treatments. Furthermore, the Pole Test was also used to study hemorrhagic stroke in an autologous blood-induced ICH model in a study conducted by Huang and Jiang (2019). It was observed that the hemorrhagic mice spent more time descending compared to the sham controls. However, treatment with dexmedetomidine significantly improved the performance of the hemorrhagic stroke mice. Overall results indicated that the Pole Test reliably assesses locomotor impairment and can be used to assess long-term motor function in rodent models of stroke. 

Data Analysis

The following parameters can be observed using the Pole Test:

• Latency to make the turn to descend the pole (Tturn)
• Time taken to descend the pole (TD)
• Time taken to reach the floor if the subject falls from the pole 
• Number of trials the subject paused during descending

Strengths and Limitations

Strengths 

The Pole Test is used to assess rodents’ locomotor function and is commonly used in rodent models of stroke. The Pole Test requires minimal equipment and is conducted on a vertical pole, which can also be placed in the subject’s home cage. The Pole Test can be used to test the effect of different treatments such as drugs or physical therapy on locomotor performance after injury. It can also be used to assess the long-term impact of ischemic stroke on locomotor performance. 

Limitations 

The Pole Test is usually performed in mice and seldom used in rats since they are heavier, making it harder for them to perform the task after stroke. If the subjects often climb over the tip of the pole, a cardboard piece needs to be attached to the tip to prevent them from climbing. The subject’s age, weight, gender, or strain and affect task performance. 

Summary

• The Pole Test is used to assess the locomotor function of rodents.

• The test involves observing whether the subject can descend a pole without falling or pausing. 

• The Pole Test can be used in rodent models of stroke or Parkinson’s disease. 

• The Pole Test can be used to test the effect of drugs on motor performance after injury.

References

Balkaya, M., Kröber, J., Gertz, K., Peruzzaro, S., & Endres, M. (2013). Characterization of long-term functional outcome in a murine model of mild brain ischemia. Journal of neuroscience methods, 213(2), 179–187. https://doi.org/10.1016/j.jneumeth.2012.12.021

Bouët, V., Freret, T., Toutain, J., Divoux, D., Boulouard, M., & Schumann-Bard, P. (2007). Sensorimotor and cognitive deficits after transient middle cerebral artery occlusion in the mouse. Experimental neurology, 203(2), 555–567. https://doi.org/10.1016/j.expneurol.2006.09.006

Huang, J., & Jiang, Q. (2019). Dexmedetomidine Protects Against Neurological Dysfunction in a Mouse Intracerebral Hemorrhage Model by Inhibiting Mitochondrial Dysfunction-Derived Oxidative Stress. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 28(5), 1281–1289. https://doi.org/10.1016/j.jstrokecerebrovasdis.2019.01.016

Ogawa, N., Hirose, Y., Ohara, S., Ono, T., & Watanabe, Y. (1985). A simple quantitative bradykinesia test in MPTP-treated mice. Research communications in chemical pathology and pharmacology, 50(3), 435–441.

Ruan, J., & Yao, Y. (2020). Behavioral tests in rodent models of stroke. Brain Hemorrhages. https://doi.org/10.1016/j.hest.2020.09.001

Zhu, B. G., Sun, Y., Sun, Z. Q., Yang, G., Zhou, C. H., & Zhu, R. S. (2012). Optimal dosages of fluoxetine in the treatment of hypoxic brain injury induced by 3-nitropropionic acid: implications for the adjunctive treatment of patients after acute ischemic stroke. CNS neuroscience & therapeutics, 18(7), 530–535. https://doi.org/10.1111/j.1755-5949.2012.00315.x