Presentation

Bioseb's "Rodent Pincher" algometer allows calibrated forceps to induce quantifiable mechanical stimulation in the animal (rats or mice) on a linear scale. The most suitable protocol was experimented by determining the effects of 3 repetitive measurements on the 2 hindpaws, respectively over long-term (9 days), mid-term (1 day) and short-term (2 hours). It was primarily developed as an analgesimeter/algometer (analgesia measurement instrument) for nociceptive tests. In this specific use, the Rodents Pincher not only represents an alternative to the "RANDALL & SELITTO" test - but also presents the following advantages when compared to the classical test:
• More ethical handling, less stressful for the animal (rat or mouse) resulting in less variable measurements
• Faster measurement, less traumatic for the tissues
• Digital measurement with metrological traceability

Furthermore, this pincher-based analgesia meter can also be used for other applications that require a controlled force or pressures values, for example :
• Sensitivity recovery after nerve crush: pinching is applied at several places over the paw to see the sensitivity recovery
• Mechanical injuries for thrombotic models
• Mechanical stimulation for in vivo electrophysiological recordings using the possibility to trigger recording on force thresholds

Comparative studies (including comparative tests with the Randall & Sellito analgesimeter) have demonstrated the accuracy of this pincher-based algometer for easy, fast and reproducible measurement of mechanical pain threshold on rat limbs. Moreover, it allowed to perform rat analagesia testing with minimal constraint, which reduces data variability.


One of these experimental research works was carried out by the team of Prof. Poisbeau in the "Nociception & Pain" department of the "Institut des Neurosciences Cellulaires et Intégratives" (Université Louis pasteur) in Strasbourg.

This work was described in two articles published in December 2005 in international reviews with a controlling committee:

• Validation method :
Calibrated Forceps: A Sensitive and Reliable Tool for Pain and Analgesia Studies, by Luis-Delgado et al. in The Journal of pain, December 2005

• Scientific work :
Inflammatory Pain Upregulates Spinal Inhibition via Endogenous Neurosteroid Production, by P. Poisbeau et al. in The Journal of neuroscience, December 2005


Operating principle

The pressure is applied in the "inter-digital" region. When used on the rat the pressure can also be applied to the tail. The instrument displays the force (in grams, newton, oz, lbs) at which the animal reacts and reports the nociception threshold.

Individual pain threshold measurements (up to 100) are stored in the internal memory, and can be downloaded post experiment. Recently an embedded statistical computation has been included in the electronic device of the algometer. This is a very useful feature that as been very well received and used by users of large numbers of tests. The display shows in real time the mean, standard deviation and variation coefficient from groups of animals (rats or mice). This feature also allows the user to cancel any analgesia test incorrectly performed.

Measured parameters

The following parameters are measured by Bioseb's rodents pincher / analgesia instrument:
• Maximum force applied as the animal reacts (movement, vocalization) (in grams, N, oz, lbs)
• Duration of the test (using Bioseb's BIO-CIS software) in seconds

Research applications

Bioseb's Rodent Pincher Algometer can be used for a variety of research on nociception and analgesia, including:
• In vivo models evaluation of pain
• Mechanisms related to mechanical nociception
• Whenever a calibrated force is necessary

Built-in components

These built-in components will make the analgesia measurement easier:
• Desktop stand for easy reading
• Footswitch to reset the zero of the rodent pincher analgesimeter while keeping hands free.
• RS232 output to transfer displayed data to a PC.
• Our new pincher design allows the mounting of custom-made bits to suit your most specific needs and applications. Please contact us if you have any special request about the pincher, and we'll do our best to cover your needs.

Options:

• Our optional RSIC software for Windows sends directly the displayed values in an Excel (MS) sheet. This allows the user direct access to a ready report and options for further analysis, without any re-copy error. Supplied with an RS232 cable.
• External pod to display a led light or produce a sound when reaching a preset threshold of force.
• Analog output and cable
• TTL output
• Additional sensor tests : our Electronic Von Frey probe, Small Animal Algometer come with their own calibration modules that are recognized by the electronic unit.

Supplied with:

• Bench control unit (batteries and main power supply)
• One rat or mice pincher, capacity 2000 grs
• Carrying case
• Footswitch for zeroing the force and having the hands "free"
• RS232 output
• User manual