[Change of Volume and Mechanical Properties of Femoral Bone in Rabbits at Different Ages with Knee Osteoarthritis under Sand-therapy].

The present paper is aimed to study the effect of sand-therapy with Uyghur medicine on biomechanical properties and femoral bone volume of the femur of osteoarthritis (OA) rabbits at two different ages. In the experiments, we injected Papain through the joint space of right knees into the bodies of New Zealand rabbits (16 in the growing group, and 16 in the mature group), and established an OA model. The 16 rabbits in the mature group were divided randomly into 2 sub-groups: 8 in control group (no sand therapy), and 8 sand-therapy group. The 16 rabbits in the growing group were divided randomly into 2 groups as well: 8 in the control group (no sand therapy), and 8 in the sand-therapy group. We carried out CT scanning four times (1 day before, 13th, 27th and 41st days after the establishment of the model, respectively). After importing the CT data to MIMICS, the different volumes of each sclerotin were recorded and change of the percentage of each sclerotins in total femur bone volume were analyzed. Finally the rabbit femurs were given three-point bending test, the elastic load and the elastic deflection were obtained and the inertia of the section, the maximum bending stresses, the bending modulus of elasticity and the structural rigidity were calculated. The experimental results showed that (1) Compared with 1 day before and 13th day after establishment of model at maturity, the cancellous bone volume increased and cortical bone volume decreased (P < 0.05), but compared with those in the control group, the cancellous bone volume of femurs decrease and cortical bone volume increased under sand-therapy (P < 0.05). Compared with those in the control group, there were no significant changes in the deflection and cross-sectional moment of inertia in the sand-therapy group (P > 0.05), but the maximum bending normal stress, maximum load, elastic modulus, and structural stiffness (P < 0.05) in the sand therapy group were larger than those in the control group. The study showed that sand-therapy in Uyghur medicine has benign effect on bone volume of the OA rabbit femur in two ages and the mechanical properties of the OA rabbit femur at the two ages induced by sand-therapy in Uyghur medicine have been improved.