H. Niki et al., POSSIBLE PARTICIPATION OF CYCLOOXYGENASE-2 IN THE RECURRENCE OF ALLERGIC INFLAMMATION IN RATS, European journal of pharmacology, 320(2-3), 1997, pp. 193-200
In the recurrence of allergic inflammation in a rat air pouch model, p
ouch fluid volume, prostaglandin E(2) concentration in the pouch fluid
, leukocyte infiltration into the pouch fluid, and granulation tissue
weight were markedly increased by the antigen challenge. To clarify th
e role of cyclooxygenase-2 in the recurrence of allergic inflammation,
the time-course of changes in protein levels of cyclooxygenase-1 and
cyclooxygenase-2 in the granulation tissue and in the infiltrated leuk
ocytes was examined by Western blot analysis. It was shown that cycloo
xygenase-1 levels in the granulation tissue and in the infiltrated leu
kocytes were not changed by the antigen challenge, but cycoloxygenase-
2 levels were increased. Furthermore, treatment with the selective cyc
looxygenase-2 inhibitor, NS-398 (cyclohexyloxy-4-nitrophenyl]-methanes
ulfonamide), suppressed the recurrence of allergic inflammation as did
the non-selective cyclooxygenase-1/cyclooxygenase-2 inhibitor, indome
thacin. The steroidal anti-inflammatory drug, dexamethasone, inhibited
the induction of cyclooxygenase-2, and suppressed the allergic inflam
mation. These findings strongly suggested that cyclooxygenase-2 induce
d by the antigen challenge plays a role in the recurrence of inflammat
ion induced by the allergic mechanism.