Early supplemental α2-macroglobulin attenuates cartilage and bone damage by inhibiting inflammation in collagen II-induced arthritis model
Funding information:
The project was supported by Grant R01AR059142 from NIH/NIAMS, NSFC 81572098, 81772415, 81772867, and 81601949, SXNSF 20150313012-6 and 201605D211024. The content is solely the responsibility of the authors and does not necessarily represent the official view of the National Institutes of Health and NSFC.
Abstract
Objective
To determine if early supplemental intra-articular α2-macroglobulin (A2M) has a chondroprotective effect in a collagen II-induced arthritis (CIA) mice model.
Methods
DBA/1 mice were randomized into four groups (n = 15/group): (a) CIA + 1.2 μg of A2M; (b) CIA + 0.8 μg of A2M; (c) CIA + 0.4 μg of A2M; (d) vehicle + phosphate-buffered saline (PBS). A2M was injected into right ankles and PBS was injected into the left ankles simultaneously as internal control at days 36, 43 and 50. The CIA inflammation clinical score and ankle thickness were recorded every other day starting on day 21 until sacrifice. Changes in inflammation were monitored by in vivo fluorescence molecular tomography (FMT). Inflammation, cartilage and bone damage were assessed with X-ray, histology and immunohistochemistry. Cartilage and inflammation-related gene expression was quantified by real-time polymerase chain reaction (PCR).
Results
All mice showed ankle inflammation on day 33. After day 43, lower clinical scores, ankle thickness and Sharp/van der Heijde method scores in A2M-treated ankles compared with PBS-treated ankles. FMT data indicated that the inflammation markers MMPSense and ProSense were significantly elevated in the PBS-treated ankles than A2M-treated ankles. Histology and X-ray analyses indicated that A2M administration resulted in lower levels of inflammatory infiltration and synovial hyperplasia, as well as more typical cartilage and bone organization with increased COL II and Aggrecan staining when compared with PBS-treated ankles. In addition, real-time PCR showed that,matrix metalloproteinase-3, -9, -13, COL X and Runx2 were significantly less expressed in A2M-treated groups than PBS-treated animals.
Conclusion
Early supplemental intra-articular A2M exerts an anti-inflammatory effect and attenuates cartilage and bone damage in a CIA model.
CONFLICT OF INTEREST
None of the authors have a conflict of interest.
