Inhibition of PI3K/Akt/NF-κB signaling by Aloin for ameliorating the progression of osteoarthritis: In vitro and in vivo studies

Osteoarthritis (OA) is a progressive and degenerative joint disease. Aloin is a bitter and yellow-brown-coloured compound from the Aloe plant and is allowed for use in foods as a "natural flavour". In our study, we examined the protective effects of Aloin on the inhibition of OA development as well as its underlying mechanism in both in vitro and vivo experiments. In in-vitro experiments, the protective effect of aloin on the anabolism and catabolism of the extracellular matrix (ECM) induced by IL-1 beta in chondrocytes by inhibiting the expression of pro-inflammatory factors, including TNF-alpha (p= 0.016), IL-6 (p = 0.006), iNOS (p= 0.001) and COX-2 (p = 0.006). Mechanistically, Aloin suppressed the IL-1 beta-induced activation of the PI3K/Akt/NF-kappa B signalling pathway cascades. Moreover, molecular docking studies demonstrated that Aloin bound strongly to PI3K. In vivo, Aloin ameliorated the OA process in the destabilization of the medial meniscus (DMM) model. In summary, our findings demonstrate that Aloin ameliorates the progression of OA via the PI3K/Akt/NF-kappa B signalling pathways, which supports Aloin as a promising therapeutic agent for the treatment of OA.