Electroacupuncture ameliorates subchondral bone deterioration and inhibits cartilage degeneration in ovariectomised rats

Objectives To investigate the effects of electroacupuncture (EA) on subchondral bone mass and cartilage degeneration in an experimental animal model of osteoarthritis (OA) induced by ovariectomy (OVX). Methods Ninety 3-month-old female Sprague-Dawley rats were randomly divided into the following three groups (n = 30 each): sham operation without treatment (control group); OVX without treatment (OVX group);, and ovariectomy with EA treatment (EA group). Rats in the EA group received EA treatment from the day of OVX. Ten rats in each group were randomly killed at 4, 8 and 12 weeks after operation. Results EA reduced urine C-terminal cross-linking telopeptide of type I collagen from 4 weeks after OVX, reduced C-terminal cross-linking telopeptide of type II collagen and body weight from 8 weeks after OVX, and increased serum 17 beta-oestradiol from 4 weeks after OVX compared with the OVX group (all p<0.01). In the EA group, trabecular bone volume ratio, trabecular thickness and trabecular number increased, and trabecular separation were reduced at each time point compared with the OVX group (p<0.05, p<0.01, respectively). In the EA group, osteoprotegerin (OPG) expression was increased and receptor activator of nuclear factor kappa-B ligand (RANKL) expression was reduced at each time point compared with the OVX group (p<0.05, p<0.01, respectively). Mankin scores and mRNA expression of matrix metalloproteinase-13 (MMP-13) were lower in EA versus OVX groups at 12 weeks after OVX (both p<0.01). Conclusion The results suggest that EA inhibits subchondral bone loss by regulating RANK/RANKL/OPG signalling and protects articular cartilage by inhibiting MMP-13 in OVX rats.