Danxiong huoxue tablets attenuate experimental heterotopic ossification after direct anterior approach total hip arthroplasty by modulating inflammation and oxidative stress

Background: Direct anterior approach total hip arthroplasty (DAA-THA) is associated with postoperative heterotopic ossification (HO), which may impair joint function. Inflammation and oxidative stress are important contributors to HO development. Danxiong Huoxue Tablets (DHT) possess potential anti-inflammatory and antioxidant activities, but their effects on postoperative HO remain insufficiently investigated. Objectives: This preclinical study aimed to evaluate the effects of DHT on experimental HO and to explore its possible association with inflammatory and oxidative stress-related signaling using a rat DAA-induced HO model and an osteogenic differentiation model of human bone marrow mesenchymal stem cells (hBMSCs). Methods: A rat DAA-induced HO model was established and treated with low- and high-dose DHT for 28 days. X-ray and histological analyses were used to evaluate ectopic bone formation. ELISA and Western blotting were employed to assess inflammatory cytokines (TNF-α, IL-6, IL-1β), oxidative stress biomarkers (SOD, GSH-Px, MDA) and related signaling proteins (NF-κB p65, NLRP3, Nrf2, HO-1). In parallel, hBMSCs were used to examine the effects of DHT on cell viability, osteogenic differentiation and related molecular changes. Results: DHT administration reduced ectopic bone formation in the rat HO model, as confirmed by imaging and histological analyses. DHT also decreased pro-inflammatory cytokine levels, improved oxidative stress-related markers, reduced NF-κB/NLRP3 pathway-related protein expression and increased Nrf2/HO-1 expression. In-vitro, DHT suppressed hBMSC osteogenic differentiation and downregulated Runx2, Osterix, BMP-2 and OCN expression. Conclusion: DHT attenuated experimental DAA-induced HO in rats and inhibited osteogenic differentiation of hBMSCs, possibly by reducing inflammatory responses and oxidative stress. These findings provide preclinical evidence supporting further investigation of DHT as a potential adjunctive strategy for preventing postoperative HO.