Catalpol Enhances Random-Pattern Skin Flap Survival by Activating SIRT1-Mediated Enhancement of Autophagy.

Random-pattern skin flap necrosis limits its application in the clinic. It is still a challenge for plastic surgeons. Catalpol is an effective ingredient extracted from Rehmannia glutinosa, which is reported to promote angiogenesis and protect against ischemic cerebral disease. The aim of our experiment is to assess whether catalpol can facilitate random flap survival and the underlying mechanisms. Male "McFarlane flap" rat models were employed to explore the protective effects of catalpol. The range of necrosis in the flap was calculated 7 days after the models were established. The flap specimens were harvested for further experiments, including angiogenesis, apoptosis, oxidative stress, and autophagy evaluation. Catalpol-treated group promoted the average survival area of the flap than that in the control group. Based on immunohistochemical staining, Western blotting, and ROS detection, we found that catalpol significantly reduces oxidative stress and apoptosis and increases angiogenesis. Hematoxylin and eosin (H&E) staining and laser Doppler images further clarified the enhancement of angiogenesis after catalpol treatment. The impact of catalpol in flap was switched by using 3-methyladenine (3MA), proving the important role of autophagy in curative effect of catalpol on skin flaps. Importantly, the ability of catalpol to regulate autophagy is mediated by the activation of sirtuin 1 (SIRT1) based on its high affinity for SIRT1. Our findings revealed that catalpol improved the viability of random skin flaps by activating SIRT1-mediated autophagy pathway.

Glycyrrhizin inhibits osteoarthritis development through suppressing the PI3K/AKT/NF-κB signaling pathway in vivo and in vitro.

Osteoarthritis (OA) is a serious and frequently occurring disease in the elderly, characterized by cartilage degeneration and proliferation of bone structure. Glycyrrhizin, a compound extracted from licorice, has been reported to have various important biological activities, such as antioxidant properties and anti-inflammatory action. However, it has not been reported whether glycyrrhizin has a positive effect on OA development. Our study aimed to evaluate the effects of glycyrrhizin on human OA chondrocytes. In the present study, we discovered that glycyrrhizin remarkably suppressed the interleukin (IL)-1ß-induced level of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and the production of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOs), metalloproteinase3 (MMP3), metalloproteinase13 (MMP13) and a disintegrin and metalloproteinase with thrombospondin motifs5 (ADAMTS5). In addition, glycyrrhizin inverted the degradation of aggrecan and collagen II. Moreover, it significantly inhibited IL-1ß-stimulated PI3K/AKT phosphorylation and NF-κB mobilization in human OA chondrocytes. In vivo, glycyrrhizin treatment prevented the destruction of cartilage in mice OA models. In summary, all the results demonstrate that glycyrrhizin may be a potential therapeutic approach for OA.

Cyanidin ameliorates the progression of osteoarthritis via the Sirt6/NF-κB axis in vitro and in vivo.

Osteoarthritis (OA) is the most prevalent form of human arthritis which is characterized by the degradation of cartilage and inflammation. As a rare Sirt6 activator, cyanidin is the major component of anthocyanins commonly found in the Mediterranean diet, and increasing evidence has shown that cyanidin exhibits anti-inflammatory effects in a variety of diseases. However, the anti-inflammatory effects of cyanidin on OA have not been reported. In the present study, we identified that cyanidin treatment could strongly suppress the expression of NO, PGE2, TNF-α, IL-6, iNOs, COX-2, ADAMTS5 and MMP13, and reduce the degradation of aggrecan and collagen II in IL-1ß-induced human OA chondrocytes, indicating the anti-inflammatory effect of cyanidin. Further investigation of the mechanism involved revealed that cyanidin could upregulate the Sirt6 level in a dose-dependent manner and Sirt6 silencing abolished the effect of cyanidin in IL-1ß-stimulated human OA chondrocytes, indicating a stimulatory effect of cyanidin on Sirt6 activation. Meanwhile, we found that cyanidin could inhibit the NF-κB pathway in IL-1ß-stimulated human OA chondrocytes and its effect may to some extent depend on Sirt6 activation, suggesting that cyanidin may exert a protective effect through regulating the Sirt6/NF-κB signaling axis. Moreover, the in vivo study also proved that cyanidin ameliorated the development of OA in surgical destabilization of the medial meniscus (DMM) mouse OA models. In conclusion, these results demonstrate that cyanidin may have therapeutic potential for the treatment of OA.