Total glucosides of paeony ameliorates oxidative stress, apoptosis and inflammatory response by regulating the Smad7-TGF-β pathway in allergic rhinitis

Total glucosides of paeony (TGP), an active ingredient extracted from the root of Paeonia alba, has been reported to display an anti-inflammatory effect. However, the effect of TGP on allergic rhinitis (AR) is still unknown. The present study aimed to assess the role of TGP in an AR mouse model. An AR mouse model was established using the ovalbumin method. The expression levels of Smad7/TGF-β pathway-related prtoeins in nasal mucosa tissues were determined by immunofluorescence, immunohistochemistry and western blotting. The severity of nasal allergic symptoms was detected by recording the frequency of sneezing and nose rubbing motions in all mice for 20 min. The levels of IgE and inflammatory cytokines, including IL-4, IL-5, IL-17 and IFN-γ, in the serum were measured by conducting ELISAs. H&E staining, periodic acid-Schiff staining and Masson staining were used to detected histopathological changes in mice. The concentrations of malondialdehyde and glutathione, and the activities of superoxide dismutase and catalase in tissue supernatant and serum were quantified using commercial assay kits. Apoptosis of nasal tissue cells was detected by performing TUNEL assays and western blotting. The expression of Smad7 was upregulated and that of TGF-β was downregulated in the nasal tissue of AR mice. Additionally, TGP regulated the Smad7/TGF-β pathway in the nasal tissue of AR mice. TGP alleviated serum IgE, nasal symptoms and histopathological changes in AR mice. Moreover, TGP ameliorated oxidative stress, cell apoptosis and inflammatory response. Smad7 small interfering RNA intervention aggravated the symptoms of AR mice via activation of the TGF-β pathway and reversed the protective effect of TGP in AR mice. TGP ameliorated oxidative stress, apoptosis and inflammatory response via the Smad7/TGF-β pathway in AR.