Histone deacetylases (HDACs) have been reported to regulate the immune response in rheumatoid arthritis (RA). The current study aimed to explore key HDACs and their molecular mechanism in RA. First, the expression of HDAC1, HDAC2, HDAC3 and HDAC8 in RA synovial tissue was determined by qRT‐PCR. The effects of HDAC2 on the proliferation, migration, invasion, and apoptosis of fibroblast‐like synoviocytes (FLS) in vitro were studied. Furthermore, collagen‐induced arthritis (CIA) rat models were established to evaluate the severity of arthritis in joints, and the levels of inflammatory factors were examined by immunohistochemistry staining, ELISA, and qRT‐PCR. Transcriptome sequencing was used to screen differentially expressed genes (DEGs) with HDAC2 silencing in the synovial tissue of CIA rat, and downstream signaling pathways were predicted by enrichment analysis. The results showed that HDAC2 was highly expressed in the synovial tissue of RA patients and CIA rats. Overexpressed HDAC2 promoted FLS proliferation, migration, and invasion and inhibited FLS apoptosis in vitro, resulting in secretion of inflammatory factors and RA exacerbation in vivo. There were 176 DEGs, including 57 downregulated and 119 upregulated genes, after silencing HDAC2 in CIA rats. DEGs were primarily enriched in Platinum drug resistance, IL‐17 as well as the PI3K‐Akt signaling pathways. CCL7, which was implicated in the IL‐17 signaling pathway, was downregulated after HDAC2 silencing. Furthermore, CCL7 overexpression aggravated the development of RA, which was demonstrated to be effectively attenuated by HDAC2 suppression. In conclusion, this study demonstrated that HDAC2 exacerbated the progression of RA by regulating the IL‐17‐CCL7 signaling pathway, suggesting that HDAC2 may be a promising therapeutic target for RA treatment.

Seed cells are an important part of bone tissue engineering. In this study, we investigated methods for the isolation, culture and identification of rat bone marrow mesenchymal stem cells (BMSCs) in vitro. BMSCs from SD rats were isolated and cultured using the whole bone marrow adherent method. Morphological observation and flow cytometry were used for the detection of cell surface markers. The osteogenic and adipogenic differentiation of cultured cells was induced and evaluated. BMSCs could be effectively isolated and purified using the whole bone marrow adherent method. The primary BMSCs cultured in vitro formed spindle-shaped, spiral and vigorous cell colonies. The flow cytometry results showed that CD90 was highly expressed on the cell surface, but CD34 and CD45 were not expressed. After culture in osteogenic and adipogenic induction medium, positive Alizarin Red and Oil Red O staining was observed, indicating the potential for multidirectional differentiation. The whole bone marrow adherent method is simple and practical, which makes the isolation, culture and amplification of BMSCs in vitro easy, and the method has little effect on cell activity and is an effective method for obtaining high-purity BMSCs.

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Background Ulnar shortening osteotomy (USO) is a common surgical procedure for the treatment of ulnar impaction syndrome (UIS). The purpose of this study was to compare the results of metaphyseal and diaphyseal USO.  Methods This retrospective study compared the clinical outcomes and complications of 32 patients who underwent diaphyseal step-cut USO (n = 10), diaphyseal oblique USO (n = 12), or metaphyseal USO (n = 10). Results Patient characteristics, ulnar variance, wrist range of motion, preoperative pain, grip strength, and functional scores (quick disability of the arm, shoulder, and hand and patient-rated wrist evaluation) were comparable. Both operation time (79.5 vs. 138/139 min) and incision length (7.80 vs. 9.67/13.00 cm) were shorter in the metaphyseal USO than in the diaphyseal oblique/step-cut USO. Compared with diaphyseal oblique/step-cut USO, metaphyseal osteotomies were associated with greater improvement in the pain on postoperative day 3 and shorter bone healing time. The requirements for implant removal were the same among the three groups. No complications were observed in any group. Conclusion Compared with diaphyseal USO, metaphyseal USO has advantages for operation time and incision length, early postoperative pain, bone healing in UIS management. The results suggested that metaphyseal USO could be widely applied to the surgical treatment of UIS. However, the long-term outcomes of these techniques still require further evaluation using more large-scale, randomized clinical trials.

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