Suppression of high bone remodelling by E’Jiao in ovariectomised rats

The current prevention options for postmenopausal osteoporosis are very limited. E'Jiao is a collagen-rich traditional Chinese medicine with the potential to prevent osteoporosis but more comprehensive investigations are lacking. This study aimed to investigate the skeletal protective effects of E'Jiao in a rat model of osteoporosis caused by ovariectomy. Female Sprague Dawley rats (n = 42) were randomly assigned into baseline, sham, ovariectomised (OVX) control, OVX-treated with low-dose (0.26 g/kg), medium dose (0.53 g/kg) and high dose E'Jiao (1.06 g/kg), as well as calcium carbonate (1% w/v) groups. Daily treatment through oral gavage was initiated 7 days after OVX. The rats were euthanised after eight weeks of treatment. Bone mineral density and content were measured at baseline, 1 and 2 months after treatment. Blood was collected for the measurement of bone remodelling markers. Femur and tibial bones were collected for histomorphometry and biomechanical strength analysis. Untreated OVX rats showed high bone remodelling marked by the increased bone formation and bone resorption markers, as well as increased mineralising surface/bone surface ratio. In addition, osteoclast surface and single-labelled surface were increased while mineral apposition rate was reduced in the untreated OVX rats. These changes were antagonised by E'Jiao at all doses. However, the structural, cellular and biomechanical parameters were not affected by ovariectomy and treatment. In conclusion, E'Jiao prevented high bone remodelling during oestrogen deficiency but a long-term study will be required to establish its effects on structural and biomechanical changes due to oestrogen deficiency.