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The osteonecrotic area of steroid-induced avascular necrosis of the femoral head (SANFH) is a hypoxic microenvironment that leads to apoptosis of transplanted bone marrow mesenchymal stem cells (BMSCs). However, the underlying mechanism remains unclear. Here, we explore the mechanism of hypoxic-induced apoptosis of BMSCs, and use the mechanism to improve the transplantation efficacy of BMSCs. Our results show that the long non-coding RNA AABR07053481 (LncAABR07053481) is downregulated in BMSCs and closely related to the degree of hypoxia. Overexpression of LncAABR07053481 could increase the survival rate of BMSCs. Further exploration of the downstream target gene indicates that LncAABR07053481 acts as a molecular "sponge" of miR-664-2-5p to relieve the silencing effect of miR-664-2-5p on the target gene Notch1. Importantly, the survival rate of BMSCs overexpressing LncAABR07053481 is significantly improved after transplantation, and the repair effect of BMSCs in the osteonecrotic area is also improved. This study reveal the mechanism by which LncAABR07053481 inhibits hypoxia-induced apoptosis of BMSCs by regulating the miR-664-2-5p/Notch1 pathway and its therapeutic effect on SANFH., (© 2023. The Author(s).)

Background/aims: Avascular necrosis of the femoral head (ANFH) is the focus and difficulty of orthopedic diseases. Recently, tissue engineering bone for this disease has shown a good therapeutic effect. The aim of the present study was to investigate the therapeutic effect of basic fibroblast growth factor (FGF-2) as cytokines transfected bone marrow mesenchymal stem cells (BMSCs) in constructing tissue-engineered bone for avascular necrosis of the femoral head., Methods: The FGF-2 gene overexpressed lentivirus-transfected rBMSCs with xenogeneic antigen-extracted cancellous bone (XACB) to construct tissue engineered bone, and the model of early avascular necrosis of the femoral head was established by lipopolysaccharide (LPS) combined with hormone. The models were randomly divided into five groups: A (control), B (XACB), C (XACB+rBMSCs), D (XACB+rBMSCs+Lv-GFP), and E (XACB+rBMSCs+Lv-FGF-2/GFP) groups. The therapeutic effect of the tissue engineered bone for the avascular necrosis of the femoral head was evaluated by gross anatomy, X-ray examination, immunohistochemistry and H&E staining., Results: The FGF-2 gene was transfected into rBMSCs (Multiplicity of infection [MOI] = 100) by lentivirus, and its efficiency was above 95%. The rBMSCs were successfully transfected overexpressing FGF-2 by qPCR and western blot. After tissue engineering bone implantation, X-ray examination and gross specimen observation revealed that the repair area in the E group was > 80% at six weeks, the defect was completely repaired at 12 weeks, and osteogenesis was stronger, when compared with the other groups. For the X-ray score, vascular area density and new bone formation area were higher, when compared with the other groups, and the difference was statistically significant (P< 0.05)., Conclusion: FGF-2 gene overexpression lentivirus transfection BMSCs combined with XACB to construct tissue engineered bone can effectively promote vascular regeneration, and improve the repair effect of avascular necrosis of the femoral head., (© 2018 The Author(s). Published by S. Karger AG, Basel.)

The study aims to investigate the effect of microRNA-34a (miR-34a) targeting Tgif2 on steroid-induced avascular necrosis of femoral head (SANFH) by regulating OPG/RANK/RANKL signaling pathway. SD rats were divided into normal control and model (RNAKL rat models) groups. The model group was further assigned into model control, negative control, miR-34a mimics and miR-34a inhibitors groups. QRT-PCR was applied to detect miR-34a, Tgif2, OPG, RANK and RNAKL mRNA expressions. Femoral head tissues were collected for Micro-CT scanning and HE staining. QRT-PCR and Western blotting were used to detect expressions of miR-34a, Tgif2, OPG, RANK, RANKL and Runx2, OPN and OC in bone tissues. Dual-luciferase reporter gene assay was used to testify the target relationship between miR-34a and Tgif2. Compared with the normal control group, the model group showed increased Tgif2, RANK and RANKL mRNA expressions, but decreased miR-34a and OPG mRNA expressions. Tgif2 mRNA expression was negatively correlated with miR-34a and OPG mRNA expressions. Micro-CT showed cystic degeneration of femoral head, with decreased bone volume/total volume (BV/TV), bone surface area/bone volume and trabecular number in the model control group compared with the normal control group. Compared with the model control group, the miR-34a mimics group showed increased BV/TV and trabecular thickness and Runx2, OPN and OC expressions, while the parameters decreased in the miR-34a inhibitors group. Compared with the normal control group, the other groups showed increased Tgif2, RANK and RANKL expressions but decreased miR-34a and OPG expressions. Compared with the model control group, Tgif2, RANK and RANKL expressions decreased and miR-34a and OPG expressions increased in the miR-34a mimics group, while the miR-34a inhibitors group had a reverse trend in contrast to the miR-34a mimics group. Tgif2 is a target gene of miR-34a. In conclusion, miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway. Impact statement miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway, which can be used as a new theoretical basis for SANFH treatment.