Osteoarthritis (OA), which is principally featured by progressive joint metabolic imbalance and subsequent degeneration of articular cartilage, is a common chronic joint disease. Arctigenin (ATG), a dietary phyto-oestrogen, has been described to have potent anti-inflammatory effects. Nevertheless, its protective effects on OA have not been clearly established. The target of our following study is to evaluate the protective effects of ATG on IL-1β-induced human OA chondrocytes and mouse OA model. Our results revealed that the ATG pre-treatment effectively decreases the level of pro-inflammatory mediators, such as prostaglandin E2 (PGE2), nitrous oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), IL-6 and tumour necrosis factor alpha (TNF-α) in IL-1β-induced human chondrocytes. In addition, ATG protects against the degradation of extracellular matrix (ECM) under the stimulation of IL-1β and the possible mechanism might be connected with the inactivation of phosphatidylinositol-3-kinase (PI3K)/Akt/nuclear factor-kappa B (NF-κB) axis. Furthermore, a powerful binding capacity between ATG and PI3K was also uncovered in our molecular docking research. Meanwhile, ATG may act as a protector on the mouse OA model. Collectively, all these findings suggest that ATG could be utilized as a promising therapeutic agent for the treatment of OA. K E Y W O R D Sarctigenin, chondrocyte, inflammation, NF-κB, osteoarthritis Shangkun Tang and Weijun Zhou contributed equally to this work.

Rapid and accurate identification of pathogens is crucial for public healthcare and patient treatment. However, the commonly used analytic tools such as molecular diagnostics and mass spectrometry are either expensive or have long turnaround times for sample purification and amplification. Here, we introduce electrochemiluminescence (ECL) microscopy with a high spatiotemporal resolution and a unique chemical contrast to image and identify single bacteria. Direct bacterial counting and classification with an accuracy of up to 90.5% is demonstrated. We further report a novel tunable ECL imaging mode which can switch from the negative contrast ECL imaging without labeling to positive contrast ECL imaging with adsorption of tris(2,2′-bipyridyl) ruthenium(II) for bacterial imaging. With this contrast tuning effect, single-molecule ECL microscopy is employed for imaging the microscopic structures of single bacteria. This work shows that ECL microscopy can offer a powerful quantitative imaging methodology with chemical information for bacterial characterization.

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