Expression of AIM2 in Rheumatoid Arthritis and Its Role on Fibroblast-Like Synoviocytes.

OBJECTIVES: To determine differences in AIM2 inflammasome expression levels between rheumatoid arthritis (RA) and osteoarthritis (OA) and to investigate the role of AIM2 in RA fibroblast-like synoviocytes (RA-FLS). METHODS: Serum AIM2 levels among health controls (HC, n = 20), OA (n = 25), and RA (n =49) patients were compared via ELISA. The different expression levels of AIM2, ASC, caspase-1, and IL-1ß between RA and OA synovium were semiquantified by qRT-PCR and immunohistochemical (IHC) staining. IHC staining was recorded by H scores, and its correlation with the ESR and CRP levels of RA patients was determined. SiRNA AIM2 was transferred to RA-FLS and its effects on the proliferation and migration via CCK-8 assay and Transwell test, respectively. RESULTS: In RA sera, the HC expressed higher level of AIM2 than OA and RA patients, and ASC, caspase-1, and IL-1ß expressed higher in RA patients than HC; no significant differences were observed between sera of OA and RA patients. However, in affected knee synovium, AIM2, ASC, caspase-1, and IL-1ß were expressed higher in RA than that of OA. Moreover, the H scores of AIM2, ASC, and IL-1ß were positively correlated with the ESR and CRP levels in RA patients. The proliferation of FLS was significantly inhibited after transferring with AIM2 siRNA to FLS. There were no differences in apoptosis and migration assay between the si-AIM2 group and the control group. CONCLUSION: AIM2 inflammasome pathway involves in the pathogenesis of RA. si-AIM2 inhibits the proliferation of RA-FLS, which may be a promising therapeutic strategy for the treatment of RA.

[What happened in the acupoint area of mouse after blood injection?]

OBJECTIVE: Autologous blood acupoint injection has practiced for treatment of various diseases, but its therapeutic mechanism remains unknown. This study aimed to explore the histological changes in the acupoint area after blood injection. METHODS: Blood samples (0.1 mL) collected from donator mice was injected in the recipient mice at the acupoint of left Zusanli (ST- 36). At 0, 6, 12, 24, 48, 72 and 96 h after the injection (3 mice at each time point), peripheral blood and muscular tissue were collected from the injection site for blood cell classification and histological study with HE staining. RESULTS: White blood cells and lymphocytes tended to increase but platelets tended to decrease at the acupoint after blood injection, but these changes were not statistically significant. Within 24 h after blood injection, acute inflammation occurred at the acupoint, and the injected blood components were infiltrated by neutrophils; a small number of monocytes were observed at the injection site, where red blood cells gradually disappeared. From 24 to 96 h, the injected area showed chronic inflammation with infiltration by mononuclear cells, macrophages, and lymphocytes, and the number of fibroblasts increased and neutrophils decreased gradually over time; the local muscle fibers were destroyed, and proliferation of fibrous tissue could be seen. CONCLUSIONS: Blood injection at the acupoints can mimic the process of hematoma absorption in the muscular tissue, and local inflammation is initiated to engulf and clear the blood components, which may be the basis for the therapeutic effects induced by acupoint stimulation.