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

Trypanosoma evansi-Infected Mice의 Allodynia 및 통증을 평가하기 위해 Mouse Grimace Scale과 관련된 Electronic von Frey

Trypanosoma evansi 감염 동물의 Allodynia 및 통증 평가를 위해 설정된 Electronic Von Frey(EvF) 장치

섭씨 21도의 온도를 12시간 조명과 12시간 어두운 주기로 조절하는 조용한 방을 설정하십시오. 각 마우스를 5제곱mm 메쉬 바닥 스탠드에 놓인 PMMA로 만든 챔버에 부드럽게 놓습니다. 기준선 및 실험적 기계적 임계값을 평가하기 전에 마우스가 30분 동안 적응하도록 합니다.그런 다음 메쉬 바닥 스탠드를 편안한 높이로 조정하여 마우스를 모든 면에서 평가할 수 있고 메쉬 바닥 개구부를 통해 복부와 네 발 모두에 쉽게 접근할 수 있도록 합니다. 챔버 아래의 표면을 흡수성 물질로 덮어 배뇨와 배변을 관리합니다. EVF 장치를 사용하는 동안 챔버 아래에 충분한 암 공간이 있는지 확인하십시오.기계적 역치 평가를 위해 EVF 장치를 설정한 후 마우스 복부를 세 개의 가상 섹션으로 나누어 복부 측정을 수행합니다. 기준선 측정값을 얻으려면 감염 48시간 전에 마우스를 챔버에 넣고 EVF 장치를 설정한 후 30분 후에 양손으로 프로브를 점차적으로 들어 올려 지정된 조직을 자극합니다. 이제 쥐가 통각 수용 행동을 보일 때까지 조직에 점진적인 압력을 가합니다.오른쪽 뒷발을 평가하려면 후퇴, 발 핥기 또는 네 발 점프와 같은 동작을 관찰하십시오. 내장 평가를 위해 갑작스러운 복부 수축, 프로브 부위를 즉시 핥거나 긁는 것 또는 네 발 점프를 관찰하십시오. 그런 다음 EVF 프로그램을 사용하여 기록된 값을 지정된 전자 장치에 저장하거나 노트북에 문서화합니다.디스플레이를 0으로 재설정합니다. 인접한 챔버에서 각 마우스를 5번 프로브하고 개별 평균 값을 계산하고 24시간 후에 기준선 측정값을 다시 평가합니다.

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 ...

연구

면역학 및 감염병학

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

Allodynia 및 통증을 평가하기 위해 마우스에서 Trypanosoma evansi 의 준비 및 접종

Mechanical Threshold Assessment of Mice Infected with Trypanosoma evansi

Trypanosoma evansi에 감염된 마우스의 기계적 역치 평가

Grimace Scale Assessment of Mice Infected with Trypanosoma evansi

Trypanosoma evansi에 감염된 마우스의 Grimace 척도 평가