Behavioral Assessment of Sensory in Animal Models of Stroke

Sensory deficits after a stroke may include decreased ability to feel touch, pain, temperature, position, or decreased ability to recognize objects held. Sensory tests typically include tests for mechanically abnormal pain, heat nociceptive sensitization, and cold nociceptive sensitization, which are commonly used to assess pain sensitivity. Strokes may cause changes in pain thresholds, so pain testing can be used as one of the functional outcome parameters.

Fig. 1. Methods used to assess mechanically evoked pain like behaviors in rodents. (Deuis et al., 2017)

Sensory Function Assessment Service

Ace Therapeutics offers different sensory testing protocols for behavioral assessment of sensory function in animal models of stroke. We have a wealth of experience and specialized scientists to avoid subjectivity and randomness. In these tests, our researchers are unaware of the treatment assignment and place the animals in the test box 30 minutes in advance to acclimatize them.

Mechanical Allodynia Testing

We use Von Frey filaments or dynamic plantar aesthesiometer for testing, which provide a good indication of mechanical allodynia in stroke animals. The test is usually performed 1 day before surgery and 1, 3, 5, 7, 10, 14, and 21 days after surgery.

	Dynamic Plantar Aesthesiometer	Von Frey Filaments
Measurement Index	Paw withdrawal threshold (g)	For rats: paw withdrawal threshold (g) For mice: paw withdrawal percentage: (number of paw withdrawals/10 trials) × 100%
Range of Normal Value	For rats: 35 g For mice: 0.8 g	For rats: around 15-20g For mice: around 10% responded to 0.07 g filament stimulation, and 40% to 0.4 g filament stimulation
Advantages	Short test duration	Easy to implement and its own set of standard procedures can facilitate a smooth learning process for beginners

Thermal Hyperalgesia Testing

We perform thermal hyperalgesia testing in a rack with thick glass panels, a radiant heat stimulator, and a Plexiglas chamber. The test is performed 1 day before surgery and on days 1, 3, 5, 7, 10, 14, and 21 after surgery. The latency of the retraction response (the time between started infrared stimulation to the withdrawal of the hind paw) is recorded in detail.

The advantage of this test is that the device stops automatically when the animal removes the hind paw, thus helping to eliminate confounding factors such as subjective judgment.

Cold Hyperalgesia Testing

We offer three methods to test cold nociceptive hypersensitivity in animal stroke models. The test is performed 1 day before surgery and on days 1, 3, 5, 7, 10, 14, and 21 after surgery.

	Acetone Test	Cold Plate Test	Cold Plantar Assay
Measurement Index	A four-point scale	The latency of the withdrawal response	Paw withdrawal latency
Range of Normal Value	For rats: the total score is below two points For mice: around one point on average	For rats: around 25 s For mice: between 15 and 20 s	For mice: around 10-15 s
Advantages	Easy to administer	More precise and objective	Easy to utilize and cheap

Ace Therapeutics provides comprehensive sensory testing services in animal stroke models. Leveraging our expertise and state-of-the-art equipment, we provide accurate and reliable data to support the effectiveness of experimental therapies to repair the brain after stroke. If you are interested in our services, please do not hesitate to contact us!

Reference

Deuis, J. R., et al. (2017). Methods used to evaluate pain behaviors in rodents. Frontiers in molecular neuroscience, 10, 284.

All of our services are intended for preclinical research use only and cannot be used to diagnose, treat or manage patients.