Although it has been suggested that
prostaglandin (PG) D(2) is involved in the pathogenesis of
allergic rhinitis, whether the inhibition of hematopoietic
PGD(2) synthase (H-PGDS) shows beneficial effects on
allergic rhinitis has been unclear. We evaluated the effects of a selective H-PGDS inhibitor,
TFC-007, on nasal symptoms on Japanese cedar pollen-induced
allergic rhinitis of guinea pigs. Sensitized animals were challenged with the pollen once a week.
TFC-007 (30mg/kg, p.o.) given once before a challenge almost completely suppressed
PGD(2) production in the nasal tissue early and late after the challenge. Although pre-treatment did not affect the incidences of
sneezing and early phase
nasal blockage, late phase
nasal blockage was partially but significantly attenuated; however, nasal
eosinophilia was not suppressed. In contrast, when
TFC-007 was given once 1.5h after the challenge, the late phase response was not affected. Collectively,
PGD(2) produced by H-PGDS early after an
antigen challenge can participate in the induction of late phase
nasal blockage, although the mechanism may be independent of eosinophil infilatration. The strategy for H-PGDS inhibition may be beneficial for
allergic rhinitis therapy.