Baricitinib

Female C57BL/6 mice at 6–8 weeks of age were purchased from the Laboratory Animal Centre of Chongqing Medical University (Chongqing, China). All animal experiments were reviewed and approved by the Ethics Committee of Chengdu Dashuo Biotechnology Co. (Dossy20210119001). The mice were housed in a room with a temperature of 22–26 °C and maintained on a 12 h light–dark cycle with free access to food and water. After adaptive feeding for 1 week, the mice were randomly divided into 3 groups: the control (PBS + 0.5% CMC-Na, n = 6), Bleomycin (7.5 mg/kg Bleomycin + 0.5% CMC-Na, n = 13), and baricitinib (7.5 mg/kg Bleomycin + 5 mg/kg baricitinib, n = 13) groups. The mice were injected subcutaneously with 100 μl of PBS or Bleomycin and intragastrically with 100 μl of 0.5% CMC-Na or baricitinib once every two days, and the body weight of the mice was simultaneously recorded. The mice were sacrificed after feeding for 4 weeks, and the dry lung was weighed. Bleomycin was purchased from Nippon Kayaku (Japan), and baricitinib was purchased from AdooQ (China).

Mice received a daily topical dose of 25 mg of commercially available imiquimod cream (5%) (Beselna Cream, Mochida Pharmaceutical) on the right ear for 10 days, with the exception of day 5 or 6. For blockade experiments, a control antibody or an anti–IL-6 (MP5-20F3), anti–TNF-α (XT3.11), or anti–IFN-γ (XMG1.2) monoclonal antibody (BioXCell) was administered on 2 consecutive days, followed by no treatment on the third day for 10 days at 400 μg/dose via i.p. injection. Mice received 6 total injections. Baricitinib (AdooQ BioScience) was administered daily by oral gavage at 10 mg/kg/dose for 10 days, with the exception of day 5.