Osteoarthritis (OA) is the most common
arthritis with a rapidly increasing prevalence.
Disease progression is irreversible, and there is no curative
therapy available. During OA onset, abnormal mechanical loading leads to excessive osteoclastogenesis and
bone resorption in subchondral bone, causing a rapid subchondral bone turnover,
cyst formation,
sclerosis, and finally, articular cartilage degeneration. Moreover, osteoclast-mediated angiogenesis and sensory innervation in subchondral bone result in abnormal vascularization and OA
pain. The
traditional Chinese medicine Panax notoginseng (PN;
Sanqi) has long been used in treatment of
bone diseases including
osteoporosis,
bone fracture, and OA. In this study we established two-dimensional/bone marrow mononuclear cell/cell membrane chromatography/time of flight mass spectrometry (2D/BMMC/CMC/TOFMS) technique and discovered that diterbutyl
phthalate (DP) was the active constituent in PN inhibiting osteoclastogenesis. Then we explored the
therapeutic effect of DP in an OA mouse model with anterior cruciate ligament transaction (ACLT). After ACLT was conducted, the mice received DP (5 mg·kg-1·d-1, ip) for 8 weeks. Whole knee joint tissues of the right limb were harvested at weeks 2, 4, and 8 for analysis. We showed that DP administration impeded overactivated osteoclastogenesis in subchondral bone and ameliorated articular cartilage deterioration. DP administration blunted aberrant H-type vessel formation in subchondral bone marrow and alleviated OA
pain assessed in Von Frey test and thermal plantar test. In RANKL-induced RAW264.7 cells in vitro, DP (20 μM) retarded osteoclastogenesis by suppressing osteoclast fusion through inhibition of the ERK/c-fos/NFATc1 pathway. DP treatment also downregulated the expression of dendritic cell-specific transmembrane
protein (DC-STAMP) and d2
isoform of the
vacuolar (H+) ATPase V0 domain (Atp6v0d2) in the cells. In conclusion, we demonstrate that DP prevents OA progression by inhibiting abnormal osteoclastogenesis and associated angiogenesis and neurogenesis in subchondral bone.