IL1B and cyclic hematopoiesis: To analyze the effect of hBMSC-EVs on the activity of pro-inflammatory signaling pathways in IL-1β-treated OA-CH, immunofluorescence and western blotting was performed to evaluate the protein expression and phosphorylation levels of Erk1/2, PI3K/Akt, p38, TAK1, and NF-κB in OA-CH.