EAE (experimental allergic encephalomyelitis) is an animal model for Central Nervous System (CNS) autoimmune disease. It is widely used as a human Multiple Sclerosis (MS) model. Although clinical signs vary according to species and strain, they include visual, sensory and motor deficits. This generally manifests as an ascending paralysis, and for research purposes is graded on a five point scale from loss of tail tone (1) to moribund (5). The course may vary from one or more episodes with short periods of remission of clinical signs to a progressive chronic state. However, for animal care, the critical aspects of this model involve the ability of the animal to reach food and water and for paralyzed animals to be protected from healthy, robust animals within the same cage. These guidelines are to establish the minimum requirements for EAE mice in order that they may receive appropriate care to minimize pain or discomfort.

Care

  1. Every animal to be injected with any substance to elicit EAE will be identified with a cage card with the letters "EAE."
  2. At the time of inoculation, a baseline weight of each animal will be obtained and recorded in a clinical chart. A cage card (or sticker) specifying "EAE mice" and date of inoculation will be placed on every applicable cage.
  3. Animals will be monitored at least daily, including weekends and holidays. As soon as an animal begins showing signs of rear limb paralysis or paresis, the following must occur:
    1. Separate paralyzed animals from non-affected animals.
    2. Supply regular pelleted rodent chow on the floor of the cage so all paralyzed mice have full and easy access.
    3. Supply water in the form of an elongated sipper tube that is accessible without the animal having to rear up on the hind limbs, or an alternative such as apple slices or Napa Nectar. If apples are used, they must be replenished daily.
  4. If an animal is unable to stand on all four feet, it must be placed in a cage by itself or with similar EAE mice that are unable to rise. Diet will be placed on the cage floor. Likewise, water bottles will either be fitted with an extra long sipper tube or an alternative (i.e., Napa nectar or small pieces of apple). If apples are used, they will be replenished daily.
  5. All mice with clinical paralysis will be monitored twice per day for the following:

    6. Problem Diagnosis/Treatment
    Dehydration Lightly pinch the skin over the neck to determine skin turgor. If skin remains in "tented" position, administer 1 ml Normal Saline or Lactated Ringer's solution subcutaneously twice per day.
    Urination At least 2-3 times per day (morning and afternoon) and additionally as needed, roll the mouse on its back and lightly palpate the abdomen to assist with voiding.
    Weight Record daily once animals reach the paralyzed state.
  6. All paralyzed mice will be monitored for skin irritation associated with urine scald and, if male, observed for penile irritation secondary to flaccid paralysis.
  7. As soon as an animal recovers from paralysis, it will be removed from the cage. No animal that has recovered from the paralyzed state will be maintained in the same cage with paralyzed animals because the following problems may occur: 1) Normal animals may walk on paralyzed animals causing discomfort or even injuries, and 2) Normal animals may eat the apples or Napa nectar intended for paralyzed animals.

Endpoint

Any of the following criteria are endpoints for immediate premature euthanasia:

a. The mouse is paralyzed in all 4 limbs and is not mentally alert.
b. The mouse is alert but exhibits paralysis in all 4 limbs for more than 24 hours.
c. The mouse exhibits dermatitis or posthitis (penile inflammation) with ulceration from excessive urinary moisture.

Approved 2/12/01; Revised 4/28/03, 2/25/08