Hai-Honghua medicinal liquor is a reliable remedy for fracture by promotion of osteogenic differentiation via activation of PI3K/Akt pathway

Abstract

Ethnopharmacological relevance: Hai-Honghua medicinal liquor (HHML), an external Chinese herbal formula preparation, is often applied to treat freshly closed tibia/fibular fractures, ankle fractures, and other bone-related disorders, but the related molecular mechanism is unclear.

Aim of the study: To evaluate the therapeutic effect of HHML in patients with tibial/fibular and ankle fractures, and to explore its related possible mechanism.

Methods and materials: A total of 182 patients with tibia/fibular fractures and 183 patients with ankle fractures were enrolled in this study. A randomized, controlled, unblinded clinical trial was designed to evaluate the therapeutic effect of HHML on tibial/fibular and ankle fractures. The chemical compositions of HHML were analyzed by the HPLC-Q-Extractive MS/MS. Furthermore, a rat tibial fracture model was established to evaluate the therapeutic effects of HHML in promoting fracture healing, and the mouse embryonic osteoblasts cell line of MC3T3-E1 was further carried out to explore the mechanisms of HHML on osteoblast differentiation.

Results: In the clinical evaluation, HHML treatment significantly shortened the time for pain and swelling in patients with tibial/fibular fractures (P < 0.01) and ankle fractures (P < 0.01), and the incidence of complications was significantly reduced as well. Subsequently, 116 constituents were identified from HHML via HPLC-Q-TOF-MS/MS analysis. In vivo, no obvious changes in weight were observed in HHML-treated rats. Moreover, the levels of bone formation markers (including osteocalcin (OCN), N-terminal propeptide of type I procollagen (PINP), alkaline phosphatase (ALP), calcium (Ca) and substance P) in rat serum were significantly increased in HHML-treated rats compared with model rats (P < 0.05). Micro-CT analysis showed bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th) of the HHML-treated rats were significantly increased (P < 0.05, vs. Model) while trabecular separation (Tb.Sp) and structure model index (SMI) values were significantly reduced (P < 0.05, vs. Model). Histological analysis showed that HHML treatment promoted the healing of fractures and cartilage repair, and increased the osteoblasts and collagen fibers. Furthermore, our results also revealed HHML could promote MC3T3-E1 cells proliferation and osteoblast differentiation via regulation of the runt-related transcription factor 2 (RUNX2), bone alkaline phosphatase (BALP), and OCN by activating phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway, which confirmed by adding PI3K chemical inhibitor of LY294002.

Conclusion: HHML treatment is a reliable remedy for fractures in tibial and ankle by promotion of osteogenic differentiation via activation of PI3K/Akt pathway.

Keywords: Fractures; Hai-honghua medicinal liquor; MC3T3-E1 cells; Osteoblast differentiation; PI3K/Akt signaling pathway.