The dissertation is devoted to the determination of morphological features of reparative osteogenesis in rats with chronic hyperglycemia, as well as to the possibility of using platelet-rich plasma to correct the process of reparative regeneration of long bone of rats under the influence of chronic hyperglycemia.
The experimental study was performed on 380 white laboratory male mature rats, which were divided into four groups: Group I – control (120 rats) with a simulated perforated defect of the tibia; Group II – 120 rats with chronic hyperglycemia and a simulated defect of the tibial diaphysis; Group III – 120 rats, which simulated chronic hyperglycemia, perforated defect of the tibia and injected into the defect platelet-rich plasma; Group IV – 20 animals to assess the state of glucose homeostasis and confirm the presence of hyperglycemia, which determined the content of fasting glucose, insulin, glycosylated hemoglobin and C-peptide in blood plasma.
Chronic hyperglycemia in animals was simulated by two weeks of watering with 10% aqueous fructose solution, a single intraperitoneal injection of streptozotocin on citrate buffer (buffer pH 4.5; dose of streptozotocin 40 mg / kg) and nicotinic acid (1 mg / kg). On the 60th day after confirmation of chronic hyperglycemia, the animals were simulated perforated defect of the tibia. Studies of morphological features of osteogenesis were performed on the 3rd, 7th, 14th, 21st and 30th days after injury, and the determination of macro- and microelements of the regenerate was performed on the 3rd and 30th days. Microscopic, ultramicroscopic, morphometric, chemical-analytical and statistical methods were used for this purpose.
It was found that reparative osteogenesis in rats without chronic hyperglycemia was characterized by timely change of all phases of regeneration. In the early stages of the process, inflammatory changes were observed in the regenerate, but on the 14th day of the study they were not detected. On the 30th day of reparative osteogenesis, intensive remodeling of reticulofibrous bone tissue into lamellar tissue took place.
Morphometric analysis revealed that bone regenerate on the 21st day in rats with chronic hyperglycemia contained (4.52 ± 0.67) mm2 inflammatory infiltrate, on the 30th day in rats with chronic hyperglycemia no signs of inflammatory reaction in the regenerate . On the 21st day of the process of osteoperation in the bone regenerate of animals with chronic hyperglycemia, the area of cartilage increased by 115.55 % (p <0.001) compared with the previous study period, but on the 30th day – decreased by 40.66 % (p <0.001) compared with the 21st day. The area of reticulofibrous bone tissue in the regeneration of rats with chronic hyperglycemia was lower by 50.72 % (p <0.001), respectively, the control group. Morphometric analysis revealed that bone regenerate on the 21st day in rats with chronic hyperglycemia still contained (4.52 ± 0.67)% of inflammatory infiltrate, which confirms the slowing of the osteoreparation process. Only on the 30th day, no signs of inflammation in the regenerate were detected under the influence of chronic hyperglycemia on the body.
It was found that the use of platelet-rich plasma in rats with chronic hyperglycemia in the early stages of reparative osteogenesis does not significantly accelerate the elimination of bone and inflammatory detritus. At the same time, there was an increase in osteoblasts and osteoclasts, and the granulation tissue was reorganized into fibroreticular connective tissue. On the 14th day, no bone detritus residues were detected.The content of sodium, calcium, iron and copper in the regenerate of rats with chronic hyperglycemia, which was injected with platelet-rich plasma on the 3rd day of osteogenesis decreased by 37.47 % (p <0.001), 22.21 % (p = 0.115), 33, 66 % (p<0.001) and 14.33% (p = 0.136), respectively, of animals with chronic hyperglycemia without correction. On the 30th day, the concentration of sodium was lower by 25.98% (p <0.001) and copper by 29.74% (p = 0.001) in the regenerate of animals with chronic hyperglycemia, which was injected with platelet-enriched plasma compared to rats with chronic hyperglycemia without correction. The concentration of iron in the regenerate of animals from the correction group was higher by 19.48% (p = 0.005) according to the control indicator, but did not differ significantly from the group of rats with chronic hyperglycemia without the use of platelet-rich plasma.
The obtained results show that under the influence of chronic hyperglycemia on the body there is a delay in the elimination of the first phase of inflammation in the area of the bone defect, which prolongs the process of reparative osteogenesis.The use of platelet-enriched plasma makes it possible to correct the negative impact of chronic hyperglycemia on reparative osteogenesis, and also promotes faster release of inflammatory infiltrate from the site of the bone defect.
