An injectable self-adaptive polymer as a drug carrier for the treatment of nontraumatic early-stage osteonecrosis of the femoral head.

Core decompression (CD) with the elimination of osteonecrotic bone is the most common strategy for treating early-stage nontraumatic osteonecrosis of the femoral head (ONFH). Adjuvant treatments are widely used in combination with CD as suitable methods of therapy. Existing augmentations have to be fabricated in advance. Here, we report a novel injectable glycerin-modified polycaprolactone (GPCL) that can adapt to the shape of the CD cavity. GPCL shows great flowability at 52.6 °C. After solidification, its compressive modulus was 120 kPa at body temperature (37 °C). This excellent characteristic enables the polymer to provide mechanical support in vivo. In addition, GPCL acts as a carrier of the therapeutic agent zoledronic acid (ZA), demonstrating sustained release into the CD region. ZA-loaded GPCL was injected into ONFH lesions to treat early-stage nontraumatic cases. Compared to that in the CD group, CD+ZA-loaded GPCL injection preserved bone density and increased the collagen level in the femoral head. At the interface between the GPCL and CD tunnel wall, osteogenesis was significantly promoted. In addition, morphological evaluations revealed that the femoral heads in the CD+ZA-GPCL group exhibited improved pressure resistance. These results suggest a strategy effective to preserve the bone density of the femoral head, thus decreasing the possibility of femoral head collapse. This novel injectable polymer has, therefore, considerable potential in clinical applications.

Melatonin increases bone mass in normal, perimenopausal, and postmenopausal osteoporotic rats via the promotion of osteogenesis.

BACKGROUND: Osteoporosis is a disease threatening the health of millions of individuals. Melatonin is found to be a potential anti-osteoporosis drug. However, whether melatonin plays a role against osteoporosis at different stages of the menopause and the underlying mechanisms are unknown. METHODS: Ovariectomy was utilized as a model of perimenopausal and postmenopausal osteoporosis. A total of 100 mg/kg melatonin, or solvent alone, was added to the drinking water of the rats over 8 weeks. Perimenopausal rats immediately received intervention following ovariectomy while postmenopausal rats received intervention 8 weeks after ovariectomy. All rats underwent overdose anesthesia following intervention after which blood samples and femurs were collected for further analysis. Rat femurs were scanned using micro-CT and examined histologically. The serum levels of melatonin and osteogenic biochemical markers were measured and the expression of osteogenesis-associated genes (Runx2, Sp7) were quantified by real-time quantitative PCR. Alkaline phosphatase (ALP) activity and the gene expression (Col1a1, Runx2, Alpl, and Bglap) were measured after bone marrow mesenchymal stem cells (BMSCs) were osteogenically induced, both with and without melatonin in vitro. ALP staining and Alizarin Red S staining were used to identify osteogenesis. RESULTS: Analysis by micro-CT and histological staining demonstrated that bone mass decreased and bone microarchitecture deteriorated over time after ovariectomy. Intervention with melatonin increased bone mass in normal, perimenopausal, and postmenopausal osteoporotic rats. Serum levels of ALP continuously increased after ovariectomy while osteocalcin levels initially rose, then decreased. Melatonin increased the serum levels of ALP and osteocalcin and mRNA expression levels of Runx2 and Sp7 in normal and postmenopausal rats, the opposite of the markers in perimenopausal rats. In vitro study demonstrated that 100 µmol/L melatonin increased the mRNA expression of Col1a1, Runx2, and Alpl three and/or seven days after intervention, and Alpl and Bglap 14 d after intervention. Melatonin increased ALP activity and the extent of ALP and matrix mineralization in the late stage of osteogenesis. CONCLUSIONS: Bone mass continuously decreased after ovariectomy, while melatonin increased bone mass and ameliorated bone metabolism in normal, perimenopausal, and postmenopausal osteoporotic rats due to the induction of osteogenic differentiation in BMSCs.

Captopril alleviates glucocorticoid-induced osteonecrosis of the femoral head by mediating the ACE2/ Ang-(1-7)/Mas receptor cascade.

The renin-angiotensin-aldosterone system (RAAS) is locally expressed in skeletal tissue and is known to affect bone health. This study investigated the therapeutic effects and potential mechanisms of the angiotensin-converting enzyme inhibitor (ACEI) captopril (CAP) in a rat model of glucocorticoid-induced femoral head necrosis (GIONFH). Bone marrow mesenchymal stem cells (mBMSC) from mice treated with dexamethasone (DEX) in vitro and methylprednisolone (MPS)-induced rats in vivo were used to explore the effects and mechanisms of CAP, respectively. Cell proliferation was detected in vitro by the CCK-8 assay, apoptosis by Annexin V-FITC-PI and Western blotting, and reactive oxygen species (ROS) by the DCFH-DA probe. Osteogenic ability was assessed by alkaline phosphatase and alizarin red staining. In vivo hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling, immunohistochemistry, enzyme-linked immunosorbent assay, micro-computed tomography, RT-PCR, and Western blotting were also performed. The in vitro data showed that CAP promotes DEX-induced mBMSC proliferation, reduces apoptosis and ROS accumulation, and promotes osteogenesis. However, these protective effects were partially counteracted by A-779, a specific Mas-receptor antagonist. In vivo experiments showed that CAP prevented MPS-induced osteonecrosis, attenuated inflammation levels, and corrected bone metabolism and bone loss while reversing MPS-induced upregulation of ACE1, AT1-receptor, and RANKL expression and downregulation of ACE2, Mas-receptor, and osteoprotegerin expression. Taken together, these findings demonstrate for the first time that CAP exerts anti-inflammatory, antioxidant, anti-apoptotic, and osteoprotective effects against GIONFH by activating the ACE2/Ang-(1-7)/Mas receptor signaling pathway, which expands a new strategy for the treatment of orthopedic diseases.

Pirfenidone attenuates synovial fibrosis and postpones the progression of osteoarthritis by anti-fibrotic and anti-inflammatory properties in vivo and in vitro.

BACKGROUND: Osteoarthritis (OA) is a disease of the entire joint involving synovial fibrosis and inflammation. Pathological changes to the synovium can accelerate the progression of OA. Pirfenidone (PFD) is a potent anti-fibrotic drug with additional anti-inflammatory properties. However, the influence of PFD on OA is unknown. METHODS: Proliferation of human fibroblast-like synoviocytes (FLSs) after treatment with TGF-ß1 or PFD was evaluated using a Cell Counting Kit-8 assay and their migration using a Transwell assay. The expression of fibrosis-related genes (COL1A1, TIMP-1, and ACTA-2) and those related to inflammation (IL-6 and TNF-α) was quantified by real-time quantitative PCR. The protein expression levels of COL1A1, α-SMA (coded by ACTA-2), IL-6 and TNF-α were measured by enzyme-linked immunosorbent assay. A rabbit model of OA was established and then PFD was administered by gavage. The expression of genes related to fibrosis (COL1A1, TIMP-1, and ADAM-12) and inflammation (IL-6 and TNF-α) was measured using RNA extracted from the synovium. Synovial tissue was examined histologically after staining with H&E, Masson's trichrome, and immunofluorescence. Synovitis scores, the volume fraction of collagen, and mean fluorescence intensity were calculated. Degeneration of articular cartilage was analyzed using a Safranin O-fast green stain and OARSI grading. RESULTS: The proliferation of FLSs was greatest when induced with 2.5 ng/ml TGF-ß1 although it did not promote their migration. Therefore, 2.5 ng/ml TGF-ß1 was used to stimulate the FLSs and evaluate the effects of PFD, which inhibited the migration of FLSs at concentrations as low as 1.0 mg/ml. PFD decreased the expression of COL1A1 while TGF-ß1 increased both mRNA and protein expression levels of IL-6 but had no effect on α-SMA or TNF-α expression. PFD decreased mRNA expression levels of COL1A1, IL-6, and TNF-α in vivo. H&E staining and synovitis scores indicated that PFD reduced synovial inflammation, while Masson's trichrome and immunofluorescence staining suggested that PFD decreased synovial fibrosis. Safranin O-Fast Green staining and the OARSI scores demonstrated that PFD delayed the progression of OA. CONCLUSIONS: PFD attenuated synovial fibrosis and inflammation, and postponed the progression of osteoarthritis in a modified Hulth model of OA in rabbits, which was related to its anti-fibrotic and anti-inflammatory properties.

Circular RNA and Messenger RNA Expression Profile and Competing Endogenous RNA Network in Subchondral Bone in Osteonecrosis of the Femoral Head.

Osteonecrosis of the femoral head (ONFH) is a common and destructive orthopedic disease, of which the pathogenesis mechanism remains elusive. Limited studies have been conducted to investigate the role of circular RNAs (circRNAs) in subchondral bone in ONFH. This study aimed to profile differential expression of circRNAs and messenger RNAs (mRNAs) in subchondral bone obtained from ONFH patients by next-generation sequencing, and explore the potential regulatory relationship of these molecules in ONFH by bioinformatics analysis. As a result, we detected 74 aberrantly expressed circRNAs and 121 differentially expressed mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses indicated several vital biological processes and signaling pathways, which are primarily related to osteogenic capacity influenced by osteoblasts and osteoclasts. Furthermore, attempting construction of protein-protein interaction network with 57 aberrant genes and competing endogenous RNA network with 3 selected circRNAs preliminarily revealed the regulatory roles and the relationships of these molecules in ONFH. In addition, the potential association of circRNAs in our networks with the molecular mechanism of ONFH was validated by real time-quantitative PCR. In conclusion, our findings may promote understanding the mechanism of ONFH, and offer a novel insight into early diagnosis and intervention of ONFH.