COMPARATIVE ANALYSIS OF MORPHOLOGICAL DISORDERS IN THE HEMOMICROCIRCULATORY BED AND SKELETAL MUSCLES OF THE HIND LIMBS IN RATS WITH BIOCHEMICAL CHANGES AT THE SYSTEMIC LEVEL DURING ACUTE ISCHEMIA-REPERFUSION UNDER CONDITIONS OF ACUTE BLOOD LOSS
Authors: Lutsyk Vitalii , Selskyy Petro 
Published: December 2023

Acute ischemia is deﬁ ned as a sudden decrease in limb perfusion, which poses a potential threat to its viability. Ischemia and subsequent reperfusion injury cause changes in cellular metabolism. Morphological disorders are signiﬁ cantly aggravated by acute blood loss. The aim of study was to establish relationship between the degree of morphological changes in the hemomicrocirculatory bed and skeletal muscles of the hind limbs of rats and biochemical changes at the systemic level in ischemia- reperfusion injury against the background of acute blood loss using neural network clustering. Biochemical study of blood serum from 30 mature white male rats weighing 200-240 g was performed. There were 6 intact animals in the control group. Ischemia was modelled by applying SWAT (Strctch- Wrap- And- Tuck) rubber tourniquets to the hind limbs of animals. The model of the early postischemic period was represented by subgroups of animals with reperfusion changes 2 hours, 1 day, and 3 days, and the model of the late postischemic period was represented by subgroups of animals with reperfusion changes 7 and 14 days after removal of the tourniquet. To predict progression of structural changes in the development of ischemia- reperfusion syndrome based on combined changes in biochemical parameters, a neural network approach was applied using the NeuroXL Classiﬁ er add-in for Microsoft Excel. In the early reperfusion period, structural changes were manifested by edema syndrome, dystrophic degenerative and destructive changes in skeletal muscle and ﬁ brillar structures with inﬂ ammatory response to ischaemic reperfusion injury under conditions of acute blood loss. In the late stage, the acute manifestations were slowed down with incomplete return to the initial state. Changes in biochemical parameters were most pronounced in animals of the early period of ischemic injury with reperfusion periods of 1 day and 3 days. Signiﬁ cant increase in creatinine content was detected on the third day, which reached its maximum during this period, exceeding the control group by 33.09 % (p<0.01). Decrease in the level of total bilirubin was found in the ﬁ rst three groups of experimental animals: after 2 hours of ischemia, the value f this indicator was 3.07 % (p>0.05) lower, after 2 hours of reperfusion – by 14.89 % (p>0.05), and after one day – by 25.06 % (p<0.05), compared with the control group. A statistically signiﬁ cant increase in the level of transaminases in the blood serum of rats at all studied groups was found. In the animals of the late postischemic period model (with reperfusion period of 7 and 14 days), there was a tendency to a gradual return of most biochemical parameters of the blood serum to control levels, but only the content of triglycerides and total bilirubin was completely equal to the control group (p>0.05). Using the cluster portrait, it was determined that the clusters with the highest severity of morphological disorders also had higher values of creatinine, alkaline phosphatase, AST, ALT and triglycerides, and lower values of total protein and bilirubin. Conclusions. Structural disorders were unidirectional and progressive in nature and increased by the end of the ﬁ rst day. Modelling of ischemia- reperfusion syndrome in the setting of acute blood loss is accompanied by signiﬁ cant changes in serum biochemical parameters during the ﬁ rst hours after blood circulation recovery with the greatest severity on the ﬁ rst and third days, indicating an increased load on the organs of homeostasis system and on the systemic nature of lesions. Analysis of cluster portraits using neural network clustering revealed that in predicting the progression of structural changes in the vascular bed and soft tissues of the extremities in the development of ischemia- reperfusion injuries, the most important is the combined increase in the levels of alkaline phosphatase, ALP and ALT.