Changes in markers of collagen metabolism in the blood serum of white rats during the filling of femur defects with implants based on polylactide and tricalcium phosphate with allogeneous mesenchymal stem cells

The use of synthetic materials in combination with osteogenesis stimulators is one of the advanced directions of the development of traumatology. The purpose of the study: based on the analysis of biochemical markers of collagen metabolism in the blood serum of laboratory rats with a femur defect, to evaluate the course of bone remodeling after filling the defect with implants based on polylactide and tricalcium phosphate with simultaneous and delayed administration of allogeneic mesenchymal stem cells (MSCs). On the model of a defect in the metaphysis of the femur in white rats, the indicators of collagen exchange in blood serum were studied: the content of protein-bound, free fractions, the amount of hydroxyproline (HOP), the ratio of the content of protein-bound HOP to free PB/F was calculated. Comparison of the results of different groups was performed using the Student-Fisher method. The difference was considered statistically significant if p<0.05. Filling the defect with implants led to a decrease in the content of protein-bound HOP by 16.69 % and 14.34 % on the 15th and 90th days (p<0.05), an increase in the content of free HOP by 74.96 %; 67.31 % and 56.74 % (p<0.001), the content of the amount of HOP by 25.37 %; 23.66 % and 18.28 % (p<0.05), and reduction of PB/F by 52.20 %; 49.90 % and 45.30 % (p<0.001) relative to intact on the 15th; 30th and 90th days. Addition of MSCs to the implants at the same time as the installation caused a decrease in the content of free HOP by 63.90 %; 54.63 % and 42.76 % on the 15th; on the 30th and 90th days (p<0.001), the total metabolite by 21.87 % and 18.58 % on the 15th and 30th days (p<0.05) and a decrease in PB/F by 47, 50 %; 43.20 %; 37.60 % on the 15th; on the 30th and 90th days (p<0.001) relative to the intact. Postponing the introduction of MSCs increased the content of free HOP by 40.48 % (p<0.001); 20.49 % and 16.58 % (p<0.05) with a lower PB/F by 38.20 %; 25.80 % and 23.40 % (p<0.05) on the 15th; 30th and 90th days relatively intact. When the defect was filled with implants without MSCs, a moderate inhibition of anabolism and rapid activation of collagen destruction was observed. With the simultaneous use of implants and MSCs, the rate of formation and intense destruction of collagen was observed. When the introduction of MSCs was delayed, a moderate rate of destruction was recorded, which most contributed to collagen metabolism.