Bone protection of MTX/DNRS gel in joints of CIA rats. a) ALP, Col I, and OCN expression levels and TRAP-stained osteoclasts in the joints in different groups. Scale bar: 100 μm. b-e) Statistics of ALP, Col I, OCN changes, and numbers of osteoclasts in the joints. f-g) BMD and BS/BV of RA rats received different treatments at day 28. h) Representative photographs and micro-CT images of RA rats received different treatments on day 28. n = 3, n.s. represents not significant, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.