Polyclonal TGF-β1 rat anti-mouse antibodies (Abcam co., Cambridge, UK); streptavidin–biotin–peroxidase complex immunohistochemical detection kit

(Fujian Maixing Biotechnology co., Fuzhou, Fujian, China); Trizol (Invitrogen Corporation, Carlsbad, CA, USA); PCR kit (Promega, Fitchburg, WI, USA); reverse transcriptase kit (Fermentas Inc., Vilnius, Lithuania); anti-phospho-Smad2/3 and Smad7 (Santa Cruz Biotechnology, Santa Cruz, CA); antibodies against β-actin (1 : 1000; Thermo Scientific IHC, Fremont, CA), tubulin (1 : 5000; Sigma); and TGF-β1 ELISA-kit (R&D Systems, Minneapolis, MN) were obtained. Forty female BABL/c mice were randomly divided into four groups with 10 mice in each group, and treated as follows. (i) In the Control group mice were treated with saline. (ii) In the LY294002 molecular weight OVA-sensitized/challenged group (OVA AZD4547 group) mice were sensitized and challenged with OVA. They were sensitized on days 0 and 14 by intraperitoneal injection of 10 μg OVA emulsified in 1 mg of aluminium hydroxide in a total volume of 200 μl. Seven days after the last sensitization, mice were exposed to OVA aerosol (2·5% weight/volume

diluted in sterile physiological saline) for up to 30 min three times per week for 8 weeks. The aerosol (particle size 2·0–6·0 μm) was generated by a nebulizer (Ultrasonic nebulizer boy037G6000, Pari, Germany) driven by filling a perspex cylinder chamber (diameter 50 cm, height 50 cm) with a nebulized solution.20 (iii) The triptolide-treated group (TRP group)

comprised mice that were sensitized and challenged as in the asthmatic group described above, and treated with 40 μg/kg triptolide by intraperitoneal injection before challenge.12,13 (iv) In the dexamethasone-treated group (DEX group) mice were sensitized and challenged as above, and were given 2 mg/kg dexamethasone by intraperitoneal injection before challenge.4,5 At 24 hr after the last challenge, bronchoalveolar lavage fluid (BALF) was obtained from the mice under anaesthesia using 1 ml sterile isotonic saline. Lavage was performed four times in each mouse and the total volume was collected separately. The volume of fluid collected in each mouse ranged from 3·0 to 3·5 ml. The lavage fluid was centrifuged at 1668.75 g at 4° for TCL 15 min. The TGF-β1 concentrations in the BALF were measured with an ELISA-kit (R&D Systems). The protocol followed the manufacturer’s instructions. Lungs were removed from the mice after killing 24 hr after the last challenge. The tissues from the left lung were fixed with 10% neutral buffered formalin. The specimens were dehydrated and embedded in paraffin. For histological examination, 5-μm sections of fixed embedded tissues were cut on a rotary microtome, placed on glass slides, deparaffinized, and stained sequentially with haematoxylin & eosin to assess the airway remodelling. Mucus production was assessed from lung sections stained with periodic acid Schiff (PAS).