Changes in Calculated Indices of Blood Serum Biochemical Indicators of Rats of Different Age after Filling of the Defect in the Metaphysis of the Femur Bone with Allogeneic Bone Implants Saturated with Mesench

Abstract

The purpose of the study was based on the analysis of calculated biochemical parameters of mineralization in the blood serum of laboratory rats to evaluate the course of metabolic processes in bone tissue after filling a defect of critical size in the metaphysis of the femur with allogeneic bone implants saturated with mesenchymal stem cells. Materials and methods. Indicators of mineralization of bone tissue in the blood serum of white rats were studied (the content of total protein, calcium, alkaline and acid phosphatase activity), the ratio of alkaline to acid phosphatase activity, as well as the degree of mineralization, were calculated. Results and discussion. In 3-month-old rats with alloimplants without mesenchymal stem cells on the 90th day, a decrease in the degree of mineralization was observed, which reflects the final stages of bone tissue remodeling by 1.13 times compared to the level of this in animals of a similar age and conditions of filling the defect on the 14th day (р = 0.008) and 1.12 times compared to the data on the 28th day of the experiment (р = 0.008). In 3-month-old rats with alloimplants saturated with mesenchymal stem cells, a decrease in the degree of mineralization on the 90th day was determined compared to that in experimental rats of a similar age and defect filling conditions on the 14th day by 1.13 times (p = 0.008), and compared with the data of the similar group on the 28th day – 1.14 times (p = 0.008), which reflects the delay in the course of the full stage of bone tissue remodeling due to the use of mesenchymal stem cells. The ratio of serum alkaline to acid phosphatase activity in 3-month-old rats with alloimplants saturated with mesenchymal stem cells was 1.32 times lower on the 14th day compared to the data of a group of the same age with alloimplants without mesenchymal stem cells (p = 0.008), and on the 90th day – by 1.12 times (p = 0.008), which also indicates a delay in the early stages of bone tissue mineralization due to the use of mesenchymal stem cells as part of alloimplants. In 12-month-old rats without the use of mesenchymal stem cells, on the 90th day, there was a decrease in the degree of mineralization by 1.10 times, in accordance with the level of this in a group of rats of a similar age and conditions of defect filling on the 14th day (р = 0.008) and by 1.09 times compared to that on the 28th day (p = 0.008), from which we can conclude about a progressive decrease in the activity of the final stages of bone tissue remodeling. The ratio of the activity of alkaline and acid phosphatase in 12-month-old rats with alloimplants without mesenchymal stem cells on the 90th day was significantly inferior to that in the corresponding 3-month-old animals by 1.12 times (p = 0.008), which indicates a lower activity of the initial stages of bone tissue mineralization in the late stages of defect healing. This indicator progressively decreased during the experiment. Thus, on the 28th day, it was 1.12 times smaller than on the 14th day, and on the 90th day – by 1.53 times less, in accordance with the data on the 14th day (p = 0.008) and by 1.36 times compared to that on the 28th day (p = 0.008). Conclusion. Treatment of experimental rats with a critical size defect in the femoral metaphysis with alloimplants saturated with mesenchymal stem cells, especially in the early stages, leads to a slowing down of bone tissue remodeling processes