Morphological and biochemical characteristics of osteogenesis during drug therapy of experimental osteoporosis

Abstract

Relevance. Osteoporosis is a clinical and economic problem on a global scale. A significant contribution to solving the problem of effective treatment of osteoporosis can be the creation of drugs based on unique biologically active compounds.The aim of the study was the morphological substantiation of the experimental model of osteoporosis and a comprehensive (multifactorial) assessment of the effectiveness of its drug therapy.Materials and methods. The study was carried out on 40 mature female Wistar rats, which comprised 6 groups. A model of osteoporosis was formed in animals of four experimental groups (6 animals in each): the first and second groups (respectively) consisted of young rats, the third and fourth — old ones. Animals of the second and fourth groups were injected with a drug tested for its ability to activate the process of osteosynthesis. Rats of the fifth and sixth groups (young and old, 8 animals each), subjected to sham surgery, served as controls. As a result of the use of the histo-morphometric method and atomic absorption spectroscopy in the diaphysis of the femur, the thickness of the layers of the compact substance, the number of bone plates and osteocytes, as well as the amount of collagen, calcium and phosphorus were determined. Using enzyme immunoassay, bone remodeling markers — osteocalcin, sclerostin, osteoprotegerin, fibroblast growth factor-23 and nuclear factor kappa-β activator ligand (RANKL) — were determined in the blood serum. Statistical processing of the data was carried out using the GraphPad PRISM (USA) program to determine the median, upper and lower quartiles. Differences were considered significant at p < 0.01.Results. Modeling of osteoporosis induces atrophic thinning of the compact substance, a decrease in the number of osteocytes and bone plates in the diaphysis of the femur, a decrease in the content of collagen, calcium and phosphorus in them, a decrease in the concentration of osteocalcin, sclerostin, fibroblast growth factor, osteoprotegerin and an increase in the concentration of RANKL in the blood plasma, more pronounced in old animals. As a result of the use of the drug X3 for the treatment of osteoporosis, the following were revealed: a significant increase in the thickness of the compact substance, the number of osteocytes and bone plates in the diaphysis, the content of collagen, calcium and phosphorus in them, an increase in the concentration of biochemical markers of osteosynthesis, and a mild imbalance of RANKL. The increase in plasma levels of markers of bone remodeling was most pronounced when the drug X3 was combined with vitamin D3.Conclusion. 1. The used surgical-endocrine method of modeling osteoporosis leads to pronounced degenerative changes in osteocytes and their derivatives in all parts of the compact bone substance, and also causes significant disturbances in the mineral composition and an imbalance of bone remodeling markers, more pronounced in senile rats. 2. The tested drug X3, used for the treatment of osteoporosis, has a high degree of effectiveness, since it stimulates regenerative osteogenesis, restores the damaged structure of bone tissue elements, its organic and mineral components. 3. The restorative effect of the drug is more pronounced in senile rats.