Cotton Pellet-Induced Granuloma in Rats [106]. This
model is based on the foreign body granuloma that can
Evidence-Based Complementary and Alternative Medicine 9
provoke by subcutaneous implantation of pellets of compressed
cotton in rats. After several days, giant cells and
undifferentiated connective tissue can be observed beside the
fluid infiltration. The amount of newly formed connective
tissue can be measured by weighing the dried pellets after
removal. More intensive granuloma formation has been
observed if the cotton pellets have been impregnated with
carrageenan. Procedure. The rats are divided into five groups
(n = 6), fasted overnight, and allowed free access to water.
The animals are administered with vehicle, standard drug
and test drugs. One hour after the first dosing, the animals
are anesthetized with anesthetic ether and 20 mg of the sterile
cotton pellet is inserted one in each axilla and groin of
rats by making small subcutaneous incision. The incisions
are sutured by sterile catgut [106] and the animals are
sacrificed by excess anesthesia on 8th day and cotton pellets
are removed surgically. Pellets are separated from extraneous
tissue and dried at 60◦C until weight become constant. The
net dry weight, that is after subtracting the initial weight of
the cotton pellet will be determined. The average weight of
the pellet of the control group as well as of the test groups
is calculated. The percent change of the granuloma weight
relatively with vehicle control is determined and statistically
evaluated, using the formula: % inhibition = Wc − Wd/Wc ×
100. Wd = difference in pellet weight of the drug treated
group; Wc = difference in pellet weight of the control group.