Induction of CIA and miR-143-3p treatment
The CIA mice model was prepared as previously described[19,20]. DBA/1J mice were used for CIA induction by bovine type II collagen (CII) Chondrex, Inc., Washington, DC, USA), acetic acid, and Freund’s adjuvant (CFA) (Sigma-Aldrich, St. Louis, MO, USA). The day of the first immunization was determined on day 0. On day 21, 0.1 mL CII emulsified with incomplete Freund’s adjuvant (IFA) (final concentration of 1 mg/mL) was i.d. in the tail, proximally to the primary injection site, to enhance immunization.
A total of 24 DBA/1J mice were randomly divided into 4 groups as follows (n = 6 per group): control group, normal mice were injected with saline (1 mL/kg, i.v.); model group, CIA mice administered with saline (1 mL/kg, i.v.); control mimics group, CIA mice were injected intravenously with a 200 μL mixture of EntransterTM-in vivo (25 μL, Engreen Biosystem Co, Ltd., Beijing, P.R. China) and control mimics (50 μg); miR-143-3p mimics group, CIA mice were injected with a 200 μL mixture of EntransterTM-in vivo (25 μL) and miR-26b-5p mimics (50 μg). MiR-143-3p mimics or the control substances were administered at day 28 and day 35 after the first immunization[21]. The paw thickness and arthritis severity were detected at day 22, 26, 30, 34, 38, 42. Mice were sacrificed on day 44, and spleens, lymph nodes, plasma, and keen joints were obtained for further studies.