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Lack of Effect of Immune Egg in Preventing Rat Paw Edema after Injection with 5% Formalin or Carrageenan

Temple University, Philadelphia, PA.

Alan Cowan, Ph. D.

Background:
Injection of formalin or carrageenan into rats results in edema of the paw. Typically, after such a challenge, paws will increasingly swell to a given maximum, after which the paws plateau in size, and remain stable at that size.

Study Design:

Rats (n=6/group) were fed varying amounts (7.5-50mg/rat) of control or immune egg for a total of 7, 14, or 53d in separate experiments. At end of the dosing period, rodents were challenged with 5% formalin or carrageenan depending on protocol.

Rat paw size and edema resulting from the challenge was determined by monitoring the displacement volume of each paw. Rats were monitored prior to challenge and 3 or 4-hr post- challenge. Indomethacin was used as the "positive" control to inhibit edema.

Results:
As measured by water displacement techniques, there were no differences in rat paw edema of animals on either immune egg or control egg after injection with formalin or carrageenan. When compared to vehicle control, indomethacin treatment resulted in significant reduction of edema.