No abstract

Time, nature, and duration of changes in microcirculation and metabolism, as well as their differences in skin and muscle tissue of the injured area during experimental explosive trauma in rats in different wound process phases, are evaluated. Experimental explosive damage was simulated on 30 Wistar rats. The total condition of rats, their activity, interest in food and water, wound area with characteristic wound healing time calculation, the volume of injured pelvic limb, and changes of microcirculation and metabolism in the skin and skeletal muscles of the paravulnar region were evaluated. The explosive damage has led to a deterioration of microcirculation and metabolism in the skin, and especially, in the muscles of the injured area. Compared to the intact group, the microcirculation deterioration resulted in a decreased constant component of perfusion in the skin and muscles by 57.6% and 40.9% and a decreased vial by 76.9% and 76.5%, respectively (p 0.05), as well as in reducing the fluorescent oxygen intake in the skin and muscles by 25.7% and 51.8% and a complex indicator of effective oxygen exchange by 81.1% and 91.9%, respectively (p 0.05). During the experiment, the microcirculation and metabolism were gradually restored, which is more pronounced in the skin, except for the repeated deterioration of the non-vascular regulation of microcirculation in the muscle (a decreased vial by 29.3% of the norm, p 0.05). Changes in the main indicators of microcirculation and metabolism indicate normal skin defect healing and unsatisfactory muscle defect repair (decreased volume of the injured limb (68% of the norm, p 0.05)), accompanied by the recurrence of extravascular disorders in the muscle. Developing new and improved existing methods of delivering biologically active drugs and drugs to the area of muscular damage in the early days after the injury, which strengthen the local blood flow and create conditions for damaged muscle regeneration, reduce the wound healing time without forming pathological scars.

Introduction. A promising method of correcting microcirculatory disorders in the area of soft tissue injury is the use of agents with antihypoxant action, which include deproteinized calf-blood hemoderivate.The aim of the work was to reveal the peculiarities of subcutaneous and intramuscular local injection of deproteinized calfblood hemoderivate on the changes of microcirculation in the skin and muscles in the experimental blast wound area.Materials and methods. The experiments were performed on 90 male Wistar rats weighing (320±20) g in compliance with international rules of work with laboratory animals. Modeling of an explosive wound of the soft tissues of the femur with mild degree of blood loss was carried out according to the original author’s method (Patent RU No. 2741238 dated 22.01.2021). After primary surgical treatment was performed paravulnarly, deproteinized calf-blood hemoderivate was injected intramuscularly, intramuscularly and subcutaneously (Actovegin drug) once in six points with an insulin syringe. Microcirculation in the skin and muscles of the injured area was assessed by laser Doppler flowmetry using the device LAKK-M (Russia). To determine the normal values of microcirculation, data obtained from healthy animals were used.Results. Local intramuscular injection into the paravular area resulted in an increase of the constant perfusion component (M) by 24.1−35.9 % (p < 0.05) and by 18.0−56.4 % (p < 0.05) in the skin and muscles during all periods of observation, an increase of the variable perfusion component (σ) in the skin by 31.4−38.0 % (p < 0.05) during 28 days and in muscles by 8.8−58.7 % (p < 0.05) during the first 14 days only, increase of Kv ratio in skin by 12.4 % (p = 0.01) early after injury (7 days) and decrease in muscles by 18.3−20.8% (p < 0.05) at 14−28 days. Local combined administration (intramuscularly and subcutaneously) of the drug around the wound promoted the increase of the constant perfusion component (M) in the skin by 23.8 % (p = 0.005) and 6.9 % (p = 0.01) at the 7th and 28th days of observation, increase of σ index in skin by 14.2−45.1 % (p < 0.007) on the 7−14 days and its decrease in muscles by 15.7 % (p = 0.009) by the end of the 7th day of observation in comparison with animals after only intramuscular injection only. Also, the coefficient of variation (Kv) with the combined route of injection was increased in the skin by 8.8−23.8 % (p < 0.009) in the first 14 days and decreased in the muscles by 15.7 % (p = 0.008) in the early period after injury (7 days) relative to its values in animals with intramuscular injection.Discussion. The results of the study allow noting the stimulating effect of deproteinized calf-blood hemoderivate on neovasculogenesis in the damaged tissues, which can be judged by the increase in the constant perfusion component (M). In addition, we can conclude that the direct endothelium-protective effect of the drug consists in the modulation of microcirculatory flow, which confirms the significant increase in the variable perfusion component (σ) throughout the experiment.Conclusion. Local paravular administration of deproteinized calf-blood hemoderivate in experimental blast wound promotes microcirculation increase in the soft tissues of the injury area. Combined (intramuscular and subcutaneous) local paravular injection of the drug allows more effective stimulation of microcirculation in the skin and muscles of the injury area.

The aim of the study was to evaluate microcirculatory and metabolic changes in damaged skeletal muscles in rats with experimental explosive trauma with acute blood loss. Material and methods. An experimental model of explosive damage to the soft tissues of the pelvic limb in rats was used to assess microcirculation and metabolic activity in the muscles of the area of the explosive wound by laser Doppler flowmetry and laser fluorescence diagnostics using the LAKK-M device. Results and discussion. It was found that during the entire follow-up period (28 days), pronounced disorders of microcirculation and metabolism were formed in the damaged muscles. Tissue perfusion was significantly reduced, which is confirmed by a change in the coefficient of variation of the microcirculation index, the value of which was lower by 36–51 % (p < 0.05) in all follow-up periods in animals from the intact group, and the maximum decrease in the indicator was observed by 28 days (6.7 (6.3; 7.4) %, at p < 0.05). Tissue metabolism was rearranged in the direction of activation of the anaerobic pathway: there was a decrease in the index of specific oxygen consumption by the tissue – by 2.3 times (p < 0.05), the fluorescent index of oxygen consumption by the tissues – by 60 % (p < 0.05), the integral index of oxygen exchange efficiency by an average of 8.5 times (p < 0.05) relative to healthy animals, which generally indicated weak oxygen utilization by the tissues. These disorders of metabolism and oxygen consumption by the tissues of the damaged area persisted throughout the experiment with a slight positive dynamics by the end of the observation period. Conclusion. The obtained data are a pathogenetic justification for the development of means for  the local correction of microcirculatory and metabolic disorders in the muscles in the case of explosive trauma in the post-traumatic period.