(±)-
Praeruptorin A (PA) is a pair of
coumarin enantiomers isolated from the root of Peucedanum praeruptorum Dunn (
PPD), a common Chinese herbal medicine for the treatment of
asthma. Considering its anti-inflammatory, anti-contractile and anti-
hyperplasia activities, the effects of PA on airway
inflammation and
airway remodeling were investigated using a murine model of chronic
asthma.
Ovalbumin-sensitized BALB/c mice were challenged with
ovalbumin to induce
asthma every other day on eight successive weeks. PA was administered intragastrically before every
ovalbumin challenge. Airway responsiveness was evaluated by a lung function analysis system 48 h after the last
ovalbumin challenge. The total and differential leukocytes in bronchoalveolar lavage fluid (BALF) were counted using a hemocytometer and Diff-Quick-stained smears. Lung tissue samples were used for
hematoxylin and
eosin,
periodic acid Schiff, Masson's trichrome and α-SMA immunohistochemistry staining. Levels of
cytokines in BALF,
immunoglobulin (Ig) E in serum as well as expression of TGF-β1 and
Smad proteins in lung tissue were measured by
enzyme-linked
immunosorbent assay, immunohistochemistry or western blot analysis. Compared with the model group, PA suppressed airway
inflammation, airway hyperresponsive and remodeling, reduced levels of
IL-4 and
IL-13 in BALF, and
IgE in serum, inhibited expression of TGF-β1 and pSmad2/3, up-regulated the expression of Smad7 in lung tissue, and also increased the levels of INF-γ in BALF. These results suggested that PA significantly suppressed airway
inflammation and
airway remodeling induced by
ovalbumin challenge, and is a potential candidate for the treatment of
asthma.