Osteoarthritis (OA) is a chronic degenerative disease that significantly impacts the quality of life of the elderly population. Recently, the pathogenesis of OA has been reported to involve autophagy in chondrocytes. Intriguingly, icariin, one of the main components of epimedium, exerts multiple pharmacological effects, including a protective effect against chondrocyte damage. Thus, we aimed to investigate the therapeutic effect of icariin on OA and its potential underlying mechanism by using a rat model of OA. After treatment with icariin or an autophagy activator (rapamycin) or inhibitor (3-methyladenine), OA chondrocyte viability was measured using the CCK-8 assay, apoptosis in the chondrocytes was evaluated using the acridine orange-propidium iodide assay and flow cytometry, and OA tissue pathological state was assessed using micro-CT scanning and safranin O staining. Furthermore, immunohistochemical staining was used to measure the expression level of Beclin-1 and immunofluorescence labeling was used to visualize LC3 expression, and western blotting was used to determine the expression levels of autophagy proteins and key proteins in the PI3K signaling pathway. The apoptotic rate of OA chondrocytes was markedly elevated by 3-methyladenine and suppressed by rapamycin and icariin; autophagy genes were drastically downregulated in the 3-methyladenine group and upregulated in the rapamycin and icariin groups; and the PI3K/AKT/mTOR signaling pathway was activated by 3-methyladenine and inhibited by rapamycin and icariin. Notably, following treatment with rapamycin and icariin, the severe pathological state in OA cartilage tissues was substantially alleviated, and this was accompanied by activated autophagy and inhibited PI3K signaling in the cartilage tissues. Taken together, these findings indicate that icariin alleviates OA by regulating the autophagy of chondrocytes by mediating PI3K/AKT/mTOR signaling.

The aim of the present study was to investigate the effect of glucocorticoids in osteoblasts and to examine the role of β-ecdysterone in the pathogenesis of glucocorticoid-induced osteoporosis. Osteoblasts were induced from bone marrow mesenchymal stem cells, which were isolated from C57BL/6 mice. Cell viability and apoptosis of osteoblasts were measured by Cell Counting Kit-8 and flow cytometry analysis, respectively. The expression of related genes and proteins was measured by reverse transcription quantitative polymerase chain reaction and western blot analysis respectively. Dose-dependent decreases in the cell proliferation and differentiation were observed in dexamethasone (Dex)-treated osteoblasts, evidenced by downregulation in the activity of alkaline phosphatasedecreased expression levels of Runt-related transcription factor 2 and osteocalcin, and upregulated expression of RANK ligand. Dex also induced apoptosis and inhibited autophagy of osteoblasts, evidenced by upregulated B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 ratio and the activation of mammalian target of rapamycin (mTOR), and decreased expression levels of Beclin-1, autophagy protein 5 and microtubule-associated protein 1 light chain 3 II. The effects on cell proliferation, apoptosis and autophagy induced by Dex were reversed by β-ecdysterone in a dose-dependent manner. Therefore, β-ecdysterone may be a promising candidate drug for the treatment of osteoporosis through inducing osteoblast autophagic activity by inactivating mTOR.

Cardiac fibroblasts (CFs) could be activated after myocardial infarction (MI). Thus, it is necessary to explore effective drugs to suppress the activation of CFs following MI. This study was designed to investigate the impacts of ellagic acid on CFs and the underlying mechanisms. The expression of histone deacetylases (HDACs) and fibrosis-related genes was detected by qRT-PCR and western blot. The Masson's Trichrome Staining assay was used to evaluate the area of cardiac fibrosis. The proliferation and migration of CFs were measured by CCK8 Kit and Transwell assay, respectively. Our results showed that ellagic acid significantly reduced protein expression of HDAC1, mRNA expression of collagen I, collagen III, MMP-2 and MMP-9 and the area of cardiac fibrosis in MI rats. In Ang II-stimulated CFs, ellagic acid (60 μmol/L) decreased the protein expression of HDAC1, collagen I, collagen III, MMP-2 and MMP-9, and inhibited cell proliferation and migration. Further, HDAC1 over-expression reversed the inhibitor effects of ellagic acid on proteins expression (collagen I, collagen III, MMP-2 and MMP-9) and proliferation and migration of CFs. The present results suggested that ellagic acid suppressed proliferation and migration of CFs by down-regulating expression of HDAC1.

Objectives To investigate the effects of β-ecdysterone on fracture healing and the underlying mechanism. Methods MTT assay was used to detect the cell viability. AO/PI and flow cytometry assays were used to determine the apoptotic rate. The expression level of RunX2, ATG7 and LC3 was evaluated by qRT-PCR and Western blot assays. X-ray and HE staining were conducted on the fractured femur. Immunohistochemical assay was used to detect the expression level of Beclin-1 and immunofluorescence assay was used to measure the expression level of LC3 in the fractured femurs. Western blot was utilized to determine the expression level of PI3K, p-AKT1, AKT1, p-mTOR, mTOR, p-p70S6K, and p70S6K. Results The ALP activity and the expression of RunX2 in fractured osteoblasts were significantly elevated, the apoptotic rate was suppressed by rapamycin, 60, and 80 μM β-ecdysterone. The state of autophagy both in fractured osteoblasts and femurs was facilitated by rapamycin and β-ecdysterone. Compared to control, Garrett score was significantly promoted in rapamycin and β-ecdysterone groups, accompanied by ameliorated pathological state. Lastly, the PI3K/AKT/mTOR pathway both in fractured osteoblasts and femurs was inhibited by rapamycin and β-ecdysterone. Conclusion β-ecdysterone might facilitate fracture healing by activating autophagy through suppressing PI3K/AKT/mTOR signal pathway.

Osteoporosis is an aging process of skeletal tissues with characteristics of reductions in bone mass and microarchitectural deterioration of bone tissue. The present study aimed to investigate the effects of glucocorticoid-induced osteoporosis on osteoblasts and to examine the roles of β-ecdysterone (β-Ecd) involved. In the present study, an in vivo model of osteoporosis was established through the subcutaneous implantation of prednisolone (PRED) into Sprague-Dawley rats, with or without a subcutaneous injection of β-Ecd (5 or 10 mg/kg body weight). Expression of Beclin-1 and microtubule-associated protein 1A/1B-light chain 3I/II and apoptosis in lumbar vertebrae tissues was measured by immunofluorescence and TUNEL assays, respectively. Serum concentration of calcium and phosphorus, and the activity of tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) were measured by biochemical assay. Reverse transcription-quantitative polymerase chain reaction and western blotting was used for detect the expression of related genes and proteins. PRED treatment inhibited bone formation by decreasing bone mineral density, and suppressing the expression of Runt-related transcription factor 2 and bone morphogenetic protein 2, while enhancing the activity of alkaline phosphatase, upregulating the expression of receptor activator of nuclear factor-κB ligand, and increasing the serum content of calcium, phosphorus and tartrate-resistant acid phosphatase in rats. Additionally, PRED was revealed to inhibit autophagy through the downregulation of Beclin-1, autophagy protein 5 and microtubule-associated protein 1A/1B-light chain 3I/II expression, whereas it induced the apoptosis, through the activation of caspase-3 and the suppression of apoptosis regulator BCL2 expression. Notably, the PRED-induced alterations in bone formation, autophagy and apoptosis were revealed to be attenuated by β-Ecd administration. In conclusion, the findings of the present study suggested that β-Ecd may be a promising candidate for the development of therapeutic strategies for the treatment of osteoporosis, through the induction of autophagy and the inhibition of apoptosis in vivo.