Osteoarthritis (OA) is a degenerative joint disease that affects both cartilage and bone. A better understanding of the early molecular changes in subchondral bone may help elucidate the pathogenesis of OA. We used microarray technology to investigate the time course of molecular changes in the subchondral bone in the early stages of experimental osteoarthritis in a rat model. We identified 2,234 differentially expressed (DE) genes at 1 week, 1,944 at 2 weeks and 1,517 at 4 weeks post-surgery. Further analyses of the dysregulated genes indicated that the events underlying subchondral bone remodeling occurred sequentially and in a time-dependent manner at the gene expression level. Some of the identified dysregulated genes that were identified have suspected roles in bone development or remodeling; these genes include Alp, Igf1, Tgf β1, Postn, Mmp3, Tnfsf11, Acp5, Bmp5, Aspn and Ihh. The differences in the expression of these genes were confirmed by real-time PCR, and the results indicated that our microarray data accurately reflected gene expression patterns characteristic of early OA. To validate the results of our microarray analysis at the protein level, immunohistochemistry staining was used to investigate the expression of Mmp3 and Aspn protein in tissue sections. These analyses indicate that Mmp3 protein expression completely matched the results of both the microarray and real-time PCR analyses; however, Aspn protein expression was not observed to differ at any time. In summary, our study demonstrated a simple method of separation of subchondral bone sample from the knee joint of rat, which can effectively avoid bone RNA degradation. These findings also revealed the gene expression profiles of subchondral bone in the rat OA model at multiple time points post-surgery and identified important DE genes with known or suspected roles in bone development or remodeling. These genes may be novel diagnostic markers or therapeutic targets for OA.

MicroRNAs (miRNAs) have been corroborated to engage in the process of cellular activities in osteoporosis. However, few researches have been conducted to expose the integrated role of miR-497, leucine-rich alpha-2-glycoprotein-1 (LRG1) and transforming growth factor beta 1 (TGF-β1)/Smads signalling pathway in osteoporosis. Thereafter, the study is set out to delve into miR-497/LRG1/TGF-β1/Smads signalling pathway axis in osteoporosis. Osteoporosis bone tissues and normal bone tissues were collected. Rat osteoporosis models were constructed via ovariectomy. Model rats were injected with restored miR-497 or depleted LRG1 to explore their roles in osteoporosis. Rat osteoblasts were extracted from osteoporosis rats and transfected with restored miR-497 or depleted LRG1 for further verification. MiR-497 and LRG1 expression in femoral head tissues and osteoblasts of osteoporosis rats were detected. TGF-β1/Smads signalling pathway-related factors were detected. MiR-497 was poorly expressed while LRG1 was highly expressed and TGF-β1/Smads signalling pathway activation was inhibited in osteoporosis. MiR-497 up-regulation or LRG1 down-regulation activated TGF-β1/Smads signalling pathway, promoted collagen type 1 synthesis and suppressed oxidative stress in femoral head tissues in osteoporosis. MiR-497 restoration or LRG1 knockdown activated TGF-β1/Smads signalling pathway, promoted viability and suppressed apoptosis of osteoblasts in osteoporosis. Our study suggests that miR-497 up-regulation or LRG1 down-regulation

Studies have shown that long non‐coding RNA (lncRNA) MEG3 plays a key role in osteoporosis (OP), but its regulatory mechanism is somewhat incompletely clear. Here, we intend to probe into the mechanism of MEG3 on OP development by modulating microRNA‐214 (miR‐214) and thioredoxin‐interacting protein (TXNIP). Rat models of OP were established. MEG3, miR‐214 and TXNIP mRNA expression in rat femoral tissues were detected, along with TXNIP, OPG and RANKL protein expression. BMD, BV/TV, Tb.N and Tb.Th in tissue samples were measured. Ca, P and ALP contents in rat serum were also determined. Primary osteoblasts were isolated and cultured. Viability, COL‐I, COL‐II and COL‐Χ mRNA expression, PCNA, cyclin D1, OCN, RUNX2 and osteolix protein expresion, ALP content and activity, and mineralized nodule area of rat osteoblasts were further detected. Dual‐luciferase reporter gene and RNA‐pull down assays verified the targeting relationship between MEG3, miR‐214 and TXNIP. MEG3 and TXNIP were up‐regulated while miR‐214 was down‐regulated in femoral tissues of OP rats. MEG3 silencing and miR‐214 overexpression increased BMD, BV/TV, Tb.N, Tb.Th, trabecular bone area, collagen area and OPG expression, and down‐regulated RANKL of femoral tissues in OP rats. MEG3 silencing and miR‐214 overexpression elevated Ca and P and reduced ALP in OP rat serum, elevated osteoblast viability, differentiation ability, COL‐I and COL‐Χ expression and ALP activity, and reduced COL‐II expression of osteoblasts. MEG3 specifically bound to miR‐214 to regulate TXNIP. MEG3 silencing and miR‐214 overexpression promote proliferation and differentiation of osteoblasts in OP by down‐regulating TXNIP, which further improves OP.

HighlightsMultiple tumor-like ectopic calcifications is a rare syndrome.Complete excisions of the ectopic calcifications were performed, without signs of recurrence in the same sites at follow-up.Incomplete excision of the ectopic calcification in the right shoulder resulted in recurrence in the same site.Subtotal parathyroidectomy with parathyroid autotransplantation appeared not to inhibit the recurrence of ectopic calcification in patients with CRF.