a) Tranexamic acid (TXA)-associated periarticular apoptosis pathways. Caspase-3 activation induced by tranexamic acid in vitro in periarticular tissues: b) and c) tenocyte; d) and e) fibroblast-like synoviocyte (FLS); and f) and g) chondrocyte single-sample multi-protein apoptotic arrays. b), d), f) Pro caspase-3 and c), e), g) cleaved caspase-3 samples were treated with 0 mg/ml, 1 mg/ml, 50 mg/ml, or 100 mg/ml of TXA for one hour. Pro and cleaved forms of caspase-3 signal pixel density plotted relative to control spots. HSP, heat shock protein; XIAP, X-linked inhibitor of apoptosis protein; cIAP, cellular inhibitor of apoptosis protein; HO-1, heme oxygenase 1; HIF1-α, hypoxia-inducible factor 1-alpha.