The Combination Treatment of Curcumin and Probucol Protects Chondrocytes from TNF-α Induced Inflammation by Enhancing Autophagy and Reducing Apoptosis via the PI3K-Akt-mTOR Pathway.

Osteoarthritis (OA) is a chronic joint disease characterized by cholesterol accumulation in chondrocytes, cartilage degeneration, as well as extracellular matrix (ECM) destruction, and joint dysfunction. Curcumin, a chemical that can reduce cholesterol levels in OA patients, also can inhibit the progression of OA. However, a high concentration of curcumin may also trigger apoptosis in normal chondrocytes. Besides curcumin, probucol that is found can also effectively decrease the cholesterol level in OA patients. Considering that high cholesterol is a risk factor of OA, it is speculated that the combination treatment of curcumin and probucol may be effective in the prevention of OA. To investigate the possible effects of such two chemicals on OA pathophysiology, chondrocyte apoptosis and autophagy behavior under inflammatory cytokine stress were studied, and specifically, the PI3K-Akt-mTOR signaling pathway was studied. Methods. Cell proliferation, colony formation, and EdU assay were performed to identify the cytotoxicity of curcumin and probucol on chondrocytes. Transwell assay was conducted to evaluate chondrocyte migration under TNF-α inflammation stress. Immunofluorescence, JC-1, flow cytometry, RT-PCR, and western blot were used to investigate the signal variations related to autophagy and apoptosis in chondrocytes and cartilage. A histological study was carried out on OA cartilage. Glycosaminoglycan (GAG) release was determined to evaluate the ECM degradation under stress. Results. Compared with a single intervention with curcumin or probucol, a combined treatment of these two chemicals is more effective in terms of protecting chondrocytes from stress injury induced by inflammatory cytokines. The promoted protection may be attributed to the inhibition of apoptosis and the blockage of the autophagy-related PI3K/Akt/mTOR pathway. Such results were also verified in vitro by immunofluorescence staining of OA chondrocytes and in vivo by immunohistochemistry staining of cartilage. Besides, in vivo studies also showed that when applied in combination, curcumin and probucol could block the PI3K-AKT-mTOR signaling pathway; promote COL-II expression; suppress P62, MMP-3, and MMP-13 expression; and inhibit TNF-α-stimulated cartilage degradation. Moreover, the combined medication could help reduce the release of ECM GAGs in OA cartilage and alleviate the severity of OA. Conclusion. A combined treatment of curcumin and probucol could be used to protect chondrocytes from inflammatory cytokine stress via inhibition of the autophagy-related PI3K/Akt/mTOR pathway both in vitro and in vivo, which might be of potential pharmaceutical value for OA prevention and therapy.

Plantamajoside attenuates isoproterenol-induced cardiac hypertrophy associated with the HDAC2 and AKT/ GSK-3ß signaling pathway.

As a compensatory response to cardiac overload, cardiac hypertrophy is closely associated with the occurrence and development of a variety of cardiovascular diseases, in which histone deacetylase 2 (HDAC2) has been reported to play an important role. Plantamajoside (PMS) is an active component extracted from Herba Plantaginis, which is a traditional Chinese medicine, and many biological activities of PMS have been reported. Here, we investigated the effects and mechanism of PMS on isoproterenol (ISO)-induced cardiac hypertrophy. ISO at 10 µmol/L was used in vitro to induce H9c2 cardiomyocyte hypertrophy. Cell viability and cell surface area were determined by MTT assay and immunocytochemistry, respectively. Furthermore, an in vivo, cardiac hypertrophy model was established by subcutaneous injection of ISO. Pathological alterations and fibrosis in the myocardium were studied by H&E and Masson's trichrome staining, respectively. Myocardial injury-related genes and proteins were detected by real-time PCR and western blotting. HDAC2 and its downstream proteins, AKT and GSK3ß, were analyzed by western blotting. Our results showed that, in vitro, PMS inhibited the ISO-induced increase in H9c2 cell surface area and the mRNA expression of ANP, BNP and Myh7. In vivo, PMS improved the ISO-induced decrease in cardiac function, inhibited the increase in cardiac anatomical parameters and alleviated the histopathological changes in cardiac tissues. Moreover, PMS inhibited the mRNA and protein expression of ANP, BNP, Myh7, COL1 and COL3. Furthermore, PMS suppressed the activity of HDAC2 and down-regulated the expression of the downstream proteins p-AKT and p-GSK3ß both in vitro and in vivo. Overall, our results indicated that PMS exerts significant cardioprotective effects against ISO-induced cardiac hypertrophy, and this protective effect may be mediated by inhibition of the HDAC2 and AKT/GSK-3ß signaling pathway.

Ligustilide attenuates nitric oxide-induced apoptosis in rat chondrocytes and cartilage degradation via inhibiting JNK and p38 MAPK pathways.

Ligustilide (LIG) is the main lipophilic component of the Umbelliferae family of pharmaceutical plants, including Radix angelicae sinensis and Ligusticum chuanxiong. LIG shows various pharmacological properties associated with anti-inflammation and anti-apoptosis in several kinds of cell lines. However, the therapeutic effects of LIG on chondrocyte apoptosis remain unknown. In this study, we investigated whether LIG had an anti-apoptotic activity in sodium nitroprusside (SNP)-stimulated chondrocyte apoptosis and could delay cartilage degeneration in a surgically induced rat OA model, and elucidated the potential mechanisms. In vitro studies revealed that LIG significantly suppressed chondrocyte apoptosis and cytoskeletal remodelling, which maintained the nuclear morphology and increased the mitochondrial membrane potential. In terms of SNP, LIG treatment considerably reduced the expression levels of cleaved caspase-3, Bax and inducible nitric oxide synthase and increased the expression level of Bcl-2 in a dose-dependent manner. The LIG-treated groups presented a significantly suppressed expression of activating transcription factor 2 and phosphorylation of Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). The inhibitory effect of LIG was enhanced by the p38 MAPK inhibitor SB203580 or the JNK inhibitor SP600125 and offset by the agonist anisomycin. In vivo studies demonstrated that LIG attenuated osteoarthritic cartilage destruction by inhibiting the cartilage chondrocyte apoptosis and suppressing the phosphorylation levels of activating transcription factor 2, JNK and p38 MAPK. This result was confirmed by histological analyses, micro-CT, TUNEL assay and immunohistochemical analyses. Collectively, our studies indicated that LIG protected chondrocytes against SNP-induced apoptosis and delayed articular cartilage degeneration by suppressing JNK and p38 MAPK pathways.

Blueberry Anthocyanins-Enriched Extracts Attenuate Cyclophosphamide-Induced Cardiac Injury.

We sought to explore the effect of blueberry anthocyanins-enriched extracts (BAE) on cyclophosphamide (CTX)-induced cardiac injury. The rats were divided randomly into five groups including normal control, CTX 100 mg/kg, BAE 80mg/kg, CTX+BAE 20mg/kg and CTX+BAE 80mg/kg groups. The rats in the three BAE-treated groups were administered BAE for four weeks. Seven days after BAE administration, rats in CTX group and two BAE-treated groups were intraperitoneally injected with a single dose of 100 mg/kg CTX. Cardiac injury was assessed using physiological parameters, Echo, morphological staining, real-time PCR and western blot. In addition, cardiotoxicity indices, inflammatory cytokines expression and oxidative stress markers were also detected. Four weeks 20mg/kg and 80mg/kg dose of BAE treatment following CTX exposure attenuated mean arterial blood pressure, heart rate and activities of heart enzymes, improved cardiac dysfunction, left ventricular hypertrophy and fibrosis. Importantly, BAE also attenuated CTX-induced LV leukocyte infiltration and inflammatory cytokines expression, ameliorated oxidative stress as well as cardiomyocyte apoptosis. In conclusion, BAE attenuated the CTX-induced cardiac injury and the protective mechanisms were related closely to the anti-inflammatory, antioxidant and anti-inflammatory characteristics of BAE.