ABSTRACT
BACKGROUND:Kidney deficiency is the main pathogenesis of osteoporosis.To study the relationship between the two major syndrome types of kidney deficiency,Kidney-Yang deficiency and Kidney-Yin deficiency,is beneficial for the development of clinical diagnosis and treatments based on the combination of disease and syndrome. OBJECTIVE:To evaluate the biomechanical differences of the rat femurs with Kidney-Yang deficiency and Kidney-Yin deficiency caused by Yougui pills,and to demonstrate the scientific efficacy of medication based on the combination of disease and syndrome in osteoporosis from a biomechanical perspective. METHODS:The bilateral ovaries of 60 female Sprague-Dawley rats were surgically removed to establish an ovariectomized osteoporosis model.At 10 weeks after modeling,all the rats were randomly divided into a Kidney-Yang deficiency group(n=30)and a Kidney-Yin deficiency group(n=30).Rats with Kidney-Yang deficiency were given gluteal intramuscular injection of hydrocortisone,while rats with Kidney-Yin deficiency were orally administered with thyroid tablet suspension,once a day,for 14 consecutive days.After successful modeling,20 rats in each group were given a suspension of Yougui pills by gavage once a day for 12 consecutive weeks and the remaining 10 rats were used as the control group without intervention.After gavage,the microstructural parameters of the bone were measured using Micro-CT scanning.Three-point bending,finite element simulation,femoral head compression,and surface indentation distribution experiments of the femurs were performed on a mechanical testing machine. RESULTS AND CONCLUSION:Micro-CT revealed that the femoral bone density,bone volume fraction,bone surface density,trabecular number,and trabecular separation were improved in the Kidney-Yin deficiency+Yougui pills group compared with the Kidney-Yin deficiency group(P＜0.05);the femoral bone volume fraction,bone surface density,trabecular number,and trabecular thickness were improved in the Kidney-Yang deficiency+Yougui pills group compared with the Kidney-Yang deficiency group(P＜0.05).The three-point bending experiment showed that the femur elastic modulus,maximum bending strength and bending fracture strength were decreased(P＜0.05)and toughness was increased(P＜0.05)in the Kidney-Yang deficiency+Yougui pills group compared with the Kidney-Yang deficiency group.Finite element simulation showed that Yougui pills could significantly improve the bending resistance of the femurs in the Kidney-Yang deficiency group,but had no significant effect on the Kidney-Yin deficiency group.The femoral head compression experiments showed that Yougui pills could enhance the ability of the femoral head to resist deformation in the Kidney-Yang deficiency group,but there was no significant difference in the effect of Yougui pills on the surface properties of the femoral head in the Kidney-Yin deficiency group and the Kidney-Yang deficiency group.To conclude,Yougui pills can significantly enhance the biomechanical properties of the osteoporotic bones with Kidney-Yang deficiency,but have no significant effect on the osteoporotic bone with Kidney-Yin deficiency.