electronic von frey (evf) apparatus set up for the evaluation of allodynia and pain in trypanosoma evansi infected animals

Assessing Pain and Allodynia in T. evansi-Infected Animals

Trypanosoma evansi is the etiological agent of the disease called &#34;surra&#34; or &#34;mal-das-cadeiras&#34; in South America1,2. It commonly affects equines and cattle, but also wild fauna, being transmitted by hematophagous bats, tabanids, and stomoxes fly bites1,3. Surra is a major disease in domestic animals, which can be fatal in the absence of the correct treatment, exhibiting nonspecific clinical signs such as anemia, loss of appetite and weight, muscle weakness, and abortion, which may vary according to the host and geographic region2,4,5,6.
The expression of allodynia and pain in infected animals during the course of the disease is still a new topic2,7. The urge to understand the pathogenesis behind these signs is an important step to improve and refine the currently used treatment by adding effective analgesic drugs to the classic trypanocidal protocol5,6. In this scenario, the possibility of replicating the disease using a murine model represents an advantage, as mice can be easily kept under controlled environments in the laboratory and therefore, yield results that are more consistent than field experiments using livestock.
A mechanical threshold is commonly obtained using an electronic von Frey (EvF) apparatus for the evaluation of allodynia in a vast number of experiments2,8,9. This device is used to assess tissue sensitivity to mechanical stimulation: once the apparatus touches the paw of the animal, through a 20-200 &#181;L tip attached to the device, the force with which the animal withdraws the paw is recorded.
Rodents are usually used as standard animals in these experiments, and most results are extrapolated to other species, as most researched diseases come from other species in which it would be difficult to conduct a controlled study. Furthermore, allodynia and pain are intimately related. The use of a specific facial scale to evaluate pain in infected mice plays an important role as a confirming adjuvant to affirm the presence of pain during the course of T. evansi infection2,10.
In this protocol, we demonstrate a novel model to evaluate allodynia and pain in mice experimentally infected with T. evansi, showing a high correlation between variables, thus proving to be a strong model. Furthermore, it requires a small number of researchers to carry out the entire procedure, decreasing the chance of human interference during the experiment. It also enables the investigator to replicate the target disease during an acute course and add several different treatment drugs in the experimental design, thereby obtaining consistent results in a short period.

Author Spotlight: Assessing Pain and Promoting Animal Welfare in Laboratory Animals Infected with Trypanosoma evansi

电子 von Frey 与小鼠鬼脸量表相关联，以评估 埃文西锥虫感染小鼠的异常性疼痛和疼痛

建立电子 von Frey （EvF） 装置，用于评估 埃文西锥虫 感染动物的异常性疼痛和疼痛

设置一个安静的房间，温度控制在 21 摄氏度，光照周期为 12 小时，黑暗周期为 12 小时。轻轻地将每只小鼠放入由 PMMA 制成的腔室中，该腔室放置在 5 平方毫米网眼地板支架上。让小鼠适应30分钟，然后评估基线和实验机械阈值。然后将网状地板支架调整到舒适的高度，以便可以从各个方面评估小鼠，并且它们的腹部和所有四只爪子都可以通过网状地板开口轻松触及。用吸收性材料覆盖腔室下方的表面，以控制排尿和排便。使用 EVF 设备时，确保腔室下方有足够的臂空间。在设置用于机械阈值评估的EVF装置后，通过将小鼠腹部分成三个虚拟部分来进行腹部测量。为了获得基线测量值，在感染前48小时，将小鼠置于腔室中，并在设置EVF装置后半小时，通过用双手逐渐升高探针来刺激指定的组织。现在，逐渐对组织施加压力，直到小鼠表现出伤害性行为。要评估右后爪，请注意缩回、舔爪子或四爪跳跃等动作。对于内脏评估，观察腹部突然回缩、立即舔舐或抓挠被探测区域，或四爪跳跃。然后将记录的值与 EVF 程序一起保存到指定的电子设备中，或将其记录在笔记本中。将显示重置为零。在相邻腔室中探测每只小鼠五次，计算它们的个体平均值，并在24小时后重新评估基线测量值。

Research

JoVE Journal

Immunology and Infection

Electronic Von Frey (EvF) Apparatus Set up for the Evaluation of Allodynia and Pain in Trypanosoma evansi Infected Animals

Electronic von Frey associated with the Mouse Grimace Scale to Assess Allodynia and Pain in Trypanosoma evansi-Infected Mice

Infectious disease pathogenesis is still a complex field to study. The course of several clinical signs, such as allodynia and pain, may be observed in ...

科研

免疫与感染

Preparation and Inoculation of Trypanosoma evansi in Mouse to Evaluate Allodynia and Pain

小鼠 埃文西锥 虫的制备和接种以评估异常性疼痛和疼痛

Mechanical Threshold Assessment of Mice Infected with Trypanosoma evansi

感染埃文西锥虫的小鼠的机械阈值评估

Grimace Scale Assessment of Mice Infected with Trypanosoma evansi

感染埃文西锥虫的小鼠的鬼脸量表评估

建立电子 von Frey （EvF） 装置，用于评估 埃文西锥虫 感染动物的异常性疼痛和疼痛

建立电子 von Frey （EvF）装置，用于评估埃文西锥虫感染动物的异常性疼痛和疼痛