Alina M. Ismailova

Background/Objectives: Hemorrhagic shock (HS) is one of the leading causes of disability and mortality in intensive care units. Animal modeling of HS is important for preclinical research to elucidate mechanisms and develop treatments. Methods: Adult male SD rats were divided into three groups, half of which were euthanized on day 8 and the other half on day 29 after HS. HS was simulated in awake animals by withdrawing blood from the carotid artery at a volume of 40% of circulating blood volume (CBV). One hour after HS, volume resuscitation therapy (VRT) was made by administering albumin-containing saline (AS) or autologous blood (AB) at 20% of CBV. Arterial pressure (AP), heart rate (HR), body temperature, blood gases, and blood metabolites, body weight gain, hemostasis, and blood cellular composition were analyzed. On days 8 and 29, bone marrow composition, organ weight, and histology were analyzed. Results: During blood withdrawal, AP dropped, HR increased, and hypothermia developed. After HS and subsequent VRT, 30% of animals receiving SA died, while all animals receiving AB survived. Following HS, a negative weight gain trend, anemia, pronounced inflammatory reaction, and coagulopathy developed. After HS, animals experienced an increase in partial oxygen pressure, a decrease in partial carbon dioxide pressure, total arterial oxygen content in arterial blood, stress-induced glycemia, and metabolic lactatemia. In bone marrow, the number of erythroid cells increased, while leukocyte and lymphocyte numbers decreased. HS resulted in increased spleen weight with increased extramedullary hematopoiesis. Ischemic kidney tissue damage with a decrease in kidney weight was observed, as well as post-ischemic accidental thymus involution with a catastrophic decrease in its weight. In addition, ischemic brain damage was observed in some animals. Animals showed a compensatory increase in hematopoiesis. All changes were less pronounced in AB-treated animals. Conclusions: We have developed a suitable model of HS, comparable to a similar condition in humans. This model can be easily reproduced and applied in most laboratories conducting preclinical studies.

The translational model of experimental stroke in rats induced by a gas embolism was created to clarify the features of stroke's development and to evaluate the neuroprotective effect of novel remedies and proven drugs. The moderately time and labor-consuming protocol allows for observing the dynamics of rapid neuron death in awake animals, providing a unique opportunity to assess the acute phase of stroke, including delirium, as well as to monitor autonomic disturbances such as changes in blood pressure, body temperature, and respiratory minute volume. Atmospheric air (100 µL) was administered by infusion through a vascular catheter placed retrogradely into the common carotid artery via the external carotid artery, using an infusion pump. Twenty-four hours after embolization, the animals exhibit stereotypical behavioral, motor deficits, and histopathological differences. By the seventh day of the experiment, a significant improvement in neurological status was observed, and the results in behavioral tests approached those of the control values. At the same time, a transition from neutrophilic to macrophage infiltration is observed in the ischemic lesion. The proposed model can be utilized in preclinical studies, as it reproduces the neuropsychiatric complications of the post-stroke period, along with the corresponding physiological, functional, and histopathological changes.

The translational model of experimental stroke in rats induced by a gas embolism was created to clarify the features of stroke's development and to evaluate the neuroprotective effect of novel remedies and proven drugs. The moderately time and labor-consuming protocol allows for observing the dynamics of rapid neuron death in awake animals, providing a unique opportunity to assess the acute phase of stroke, including delirium, as well as to monitor autonomic disturbances such as changes in blood pressure, body temperature, and respiratory minute volume. Atmospheric air (100 µL) was administered by infusion through a vascular catheter placed retrogradely into the common carotid artery via the external carotid artery, using an infusion pump. Twenty-four hours after embolization, the animals exhibit stereotypical behavioral, motor deficits, and histopathological differences. By the seventh day of the experiment, a significant improvement in neurological status was observed, and the results in behavioral tests approached those of the control values. At the same time, a transition from neutrophilic to macrophage infiltration is observed in the ischemic lesion. The proposed model can be utilized in preclinical studies, as it reproduces the neuropsychiatric complications of the post-stroke period, along with the corresponding physiological, functional, and histopathological changes.

This work shows that age-related arterial hypertension in Wistar rats develops with age, in 52% of 18-monthold animals versus 33% of 3-month-old animals. Effects of Taxifolin at a dose of 100 mg/kg, administered intraperitoneally for a week, on blood pressure (BP) and biochemical parameters in 18-month-old and 3-month-old animals were studied. The experimental animals were divided into two groups, those normotensive (BP115 mmHg). It was shown that a weekly course of Taxifolin leads to a significant decrease in blood pressure in hypertensive 18-month-old animals with no effect on blood pressure in normotensive animals. In addition, some age-related changes in the biochemical parameters of blood under the influence of Taxifolin were revealed.

Arterial gas embolism can result from complications related to medical and surgical procedures, as well as a direct entry of air into the systemic circulation due to the disruption of the alveolar-capillary barrier. Since air in the arterial circulation can lead to organ ischemia, this life-threatening pathology requires prompt intervention. In this study, we demonstrated the effectiveness of using a hyperoxic heated helium-oxygen mixture in cerebral arterial air embolism. Oxygen therapy under normobaric conditions did not affect the outcome of arterial air embolism. A continuous inhalation session for 30 min, or intermittent inhalation sessions 3 times for 5 min each, eliminated foci of ischemic stroke in rats.

To preclinically study the effectiveness of new antihypertensive drugs, various animal hypertension models are used. However, most of them do not correspond to primary hypertension, which develops in people with age. We used male Wistar rats of 4, 10, 12 and 18 months old. The animals were divided according to systolic blood pressure (SBP) into normotensive (SBP ≤ 114 mmHg) or hypertensive (SBP ≥ 115 mmHg). Within hypertensive animals, two cohorts were distinguished—with SBP below and above 125 mmHg. The animals received 100 µg/kg of taxifolin intraperitoneally for 7 days. A significant difference was shown between animals with SBP above and below 115 mmHg, as well as between cohorts of hypertensive animals with SBP above and below 125 mmHg within each age. The number of animals with elevated SBP increased with age both for clusters with an SBP above 115 mmHg and for cohorts with an SBP above 125 mmHg. Administration of taxifolin led to a significant decrease in the SBP only in hypertensive animals. A physiological model of age-related hypertension was obtained in male Wistar rats. It has been shown that hypertension develops and worsens with age. In preclinical studies, it should be taken into account that drugs may have different effects depending on the initial SBP of the animals.

Background/Objectives: Intratracheal administration of bleomycin (BLM) to laboratory rodents is a standard, widely used technique used to model pulmonary fibrosis (PF). BLM, as a modeling agent, is produced mainly in the form of two salts—sulfate and chloride. We compared the results of modeling PF in SD rats by intratracheal administration of BLM sulfate and BLM chloride. Methods: Healthy mature male SD rats were used. PF was modeled by intratracheal administration of BLM sulfate and BLM chloride at a dose of 3 mg/kg. The criteria for the development of PF included body weight gain, changes in respiratory parameters, relative lung weight, cellular composition of broncho-alveolar fluid (BALF), histological assessment of the severity of PF with trichrome Masson staining. Results: Intratracheal administration of both BLM salts led to the development of pronounced PF, which was determined by changes in all of the measured parameters relative to control animals. There were no significant differences between the BLM sulfate and BLM chloride groups in body weight gain, hydroxyproline content, and histological evaluation. However, significant differences were identified in the cellular composition of BALF—a significant increase in alveolar macrophages and neutrophils levels in animals treated with BLM sulfate. Conclusions: Intratracheal administration of both BLM salts led to the development of severe PF; however, the inflammatory process in animals receiving BLM sulfate was more pronounced and prolonged than in animals receiving BLM chloride, which in the former, when observed more than 21 days after modeling, can lead to more severe PF.

The development of novel anticoagulants requires a comprehensive investigational approach that is capable of characterizing different aspects of antithrombotic activity. The necessary experiments include both in vitro assays and studies on animal models. The required in vivo approaches include the assessment of pharmacokinetic and pharmacodynamic profiles and studies of hemorrhagic and antithrombotic effects. Comparison of anticoagulants with different mechanisms of action and administration types requires unification of the experiment scheme and its adaptation to existing laboratory conditions. The rodent thrombosis models in combination with the assessment of hemostasis parameters and hematological analysis are the classic methods for conducting preclinical studies. We report an approach for the comparative study of the activity of different anticoagulants in vivo, including the investigation of pharmacodynamics and the assessment of hemorrhagic effects (tail-cut bleeding model) and pathological thrombus formation (inferior vena cava stenosis model of venous thrombosis). The reproducibility and uniformity of our set of experiments were illustrated on unfractionated heparin and dabigatran etexilate (the most common pharmaceuticals in antithrombic therapy) as comparator drugs and an experimental drug variegin from the tick Amblyomma variegatum. Variegin is notorious since it is a potential analogue of bivalirudin (Angiomax, Novartis AG, Basel, Switzerland), which is now being actively introduced into antithrombotic therapy.

A short synthetic peptide from the C-terminal part of the caveolin-3 structure was tested for experimental autoimmune encephalomyelitis (EAE) treatment in rats. The structure–function similarity established between the novel synthetic peptide of pCav3 and the well-known immunomodulator immunocortin determined pCav3’s ability to reduce EAE symptoms in Dark Agouti (DA) rats injected with pCav3 (500 µg/kg). pCav3 was found to interfere with the proliferation of lymphocytes extracted from the LNs of DA rats primed with homogenate injection, with IC₅₀ = 0.42 μM (2.35 mcg/mL). pCav3 affected EAE in a very similar manner as immunocortin. The high degree of homology between the amino acid sequences of pCav3 and immunocortin corresponded well with the therapeutic activities of both peptides, as demonstrated on EAE. The latter peptide, possessing a homologous structure to pCav3, was also tested on EAE to explore whether there were structural restrictions between these peptides implied by the MHC-involved cell machinery. Consequently, immunocortin was further examined with a different autoimmune disease model, collagen-induced arthritis (CIA), established in Sprague–Dawley rats. CIA was established using an intentionally different genetic platform than EAE. Based on the results, it was concluded that the effectiveness of pCav3 and immunocortin peptides in EAE rat model was almost identical, but differed in the rat model of rheumatoid arthritis; thus, efficacy may be sensitive to the MHC type of animals used to establish the autoimmune disease model.