RU2541831C2 - Method for simulation and pharmaceutical correction of acute pulmonary injury experimentally - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: pulmonary injury is simulated by the intratracheal administration of acetone 0.03ml into rats. One hours later, a combined solution containing 7.2% sodium chloride and 6% hydroxyethyl starch, in an amount of 4 ml/kg is administered intravenously once.

EFFECT: reducing animal mortality by reducing hypoxemia and an area of the infiltrative pulmonary injury, preventing an alveolar pulmonary oedema and a degree of haemorrhagic impregnation.

2 dwg, 2 tbl

Description

The invention relates to medicine and can be used in pulmonology, emergency therapy and resuscitation.

Syndrome of acute lung injury (SROF) and its most severe form - acute respiratory distress syndrome (ARDS) are one of the main complications of various life-threatening conditions. According to the latest data from The National Heart, Lung, and Blood Institute ARDS Clinical Trials Network, the incidence of SOPL / ARDS reaches 75 per 100,000 population per year, although it was previously believed that this indicator varies from 1.5 to 8.3 per 100,000 inhabitants in year. Unfortunately, we have to admit that the mortality rate of patients with SOPL / ARDS varies from 40 to 60% (Leroy.O., Vandenbussche C, Coffmier C, et al. Cammunity - acquired aspiration pneumonia in intensive care units. Epidemiological and prognosis data. Am j Respir Crit Care Med 1997; 156: 1922-29).

The basis of SALP therapy is mechanical ventilation (mechanical ventilation), which is aimed at maintaining gas exchange and allows you to buy time for the processes of sanogenesis. High mortality in SALP is associated not only with hypoxemia and gas exchange in the lungs, but also with organ failure and secondary pulmonary complications (aspiration pneumonia, lung abscess, etc.), as well as damaging factors of mechanical ventilation (Kazakh National Medical University named after S.D. Asfendiyarova, Department of Anesthesiology and Intensive Care with an emergency course, Methodological recommendations, Syndrome of acute lung injury (SOPL): current understanding of the pathogenesis of the clinic and intensive care. Ata, 2011). The interest of doctors of various specialties in this pathology is due primarily to the fact that despite intensive scientific studies of the pathogenesis and therapy of ARDS, over the past 20 years there has been no noticeable success in clinical practice. The low efficiency of therapy for SOPL shows that the main task - reducing mortality, remains unresolved (Diagnosis and intensive care of acute lung injury syndrome and respiratory distress syndrome. Kolesnichenko AP, Gritsan AI Materials of the international conference on respiratory therapy. Krasnoyarsk, August 2005).

From the experience gained in treating adult patients with acute respiratory distress syndrome of various origins, some should be highlighted. Since in patients with ARDS, a violation of the function and production of endogenous surfactant is proved, as well as a decrease in its quantity (Griese M. Pulmonary surfactant in health and human lung diseases: state of the art. Eur Respir J 1999; 13: 1455-76) , there are methods of introducing exogenous surfactant in order to restore normal surface tension in the alveoli. In addition, surfactant preparations can reduce the risk of nosocomial pneumonia due to their antibacterial properties. Surfactant is prescribed endotracheally either in the form of installations during bronchoscopy, or through a nebulizer. According to Gregory et al., Bronchoscopic installations of bovine surfactant at a dose of 100 mg / kg 4 times a day significantly improve oxygenation for 120 hours and, in addition, can improve the survival of patients with ARDS. In a large (over 700 patients) randomized study, the effect of inhaled synthetic surfactant (Exosurf) on the survival of ARDS patients was not shown, so the study of this group of drugs is still ongoing (Anzueto A, Baughman RP, Guntupalli KK et al. Aerosolized surfactant in adults with sepsis- induced acute respiratory distress syndrome. N Engl J Med 1996; 334: 1417-21).

Despite the theoretical role of glucocorticosteroids (GCS) in ARDS (action on inflammatory cytokines), their effectiveness in the early phase of ARDS is virtually zero. Moreover, in some studies, an increased risk of developing infectious complications and even an increase in the mortality rate of patients with ARDS with the appointment of GCS were demonstrated. However, the role of corticosteroids may be significant in the late stages of ARDS (later than the 5-10th day). A recent study showed the effectiveness of methyl-prednisolone in "stressful" doses (starting from 2 mg / kg per day with a gradual dose reduction, duration of therapy 32 days) in patients with the fibro-proliferative phase of ARDS: improving lung injury index, multiple organ failure, and patient survival (88% versus 38% in the control group) (Meduri GU, Headley AS, Golden E et al. Effect of prolonged methylprednisolone therapy in unresolving acute respiratory distress syndrome, a randomized controlled trial. JAMA 1998; 280: 159-65).

There is strong evidence for the role of free radicals in the pathogenesis of ARF / ARDS: their damaging effect on cell and matrix proteins, lipids, and nucleic acids has been proven. Antioxidant defense systems in patients with ARDS are depleted: for example, the concentration and activity in biological membranes of one of the most active components of antioxidant defense - glutathione - is significantly reduced. The administration of glutathione precursors, N-acetylcysteine and procysteine, enhances the synthesis of endogenous glutathione. A number of randomized trials have shown that the administration of medium doses of N-acetylcysteine (70 mg / kg / s) and procysteine (63 mg / kg / s) accelerates the resolution of APL / ARDS, increases cardiac output, but does not affect patient survival (Bernard GR, Wheeler AP, Arons MM et al. A trial of antioxidants N-acetylcysteine and procysteine in ARDS. The Antioxidant in ARDS Study Group. Chest 1997; 112: 164-72).

With interstitial pulmonary edema, transfusion of hydroxyethyl starch (HES) that does not penetrate the vascular endothelium can reduce the severity of interstitial edema (Groeneveld J. // Crit Care. - 2000. - Vol.4. - Suppl. 2. - P. S16-S20) . In experimental studies on animals, the ability of HES to reduce the severity of edema in burns, ischemic / reperfusion injury, and sepsis was shown. There are reports of the ability of HES solutions to reduce capillary leakage with increased pulmonary vascular permeability. However, these data need further clinical study (Vincent J.-L., Wilkes M.M., Navickis R.J. // Br. J. Anaesth. - 2003. - Vol. 91. - P. 625-630).

Scientists from the USA and Canada, led by Z.Safdar, found that the introduction of hyperosmolar solutions into the bloodstream stimulates the metabolism in the cells that form the capillary barrier of the lungs and significantly improves its quality. It was previously found that endothelial cells of the capillaries of the lungs, when exposed to hyperosmolar solutions (e.g. sucrose), begin to actively synthesize and accumulate protein substances that can affect the barrier properties of capillaries. During an animal experiment, it was found that the introduction of hyperosmolar solutions into the blood changes the conductivity of capillaries and significantly improves the quality of the capillary barrier of the lungs. In particular, these drugs protect the lung tissue from damage by hydrogen peroxide, thrombin, tumor necrosis factor and other chemical and biological agents (Clin. J. // Invest. - 2003. - Vol. 112. - P. 1541-1549).

There is a method of treating acute respiratory distress syndrome, in which, under conditions of artificial ventilation of the lungs with positive pressure at the end of the exhalation, the level of positive pressure at the end of the exhalation is set above the pre-selected optimal 4-8 cm water. Art. After 10-15 minutes, perfluorocarbon is introduced in the form of an aerosol. The introduction is carried out using a nebulizer for 10-15 minutes (RU 2265434, IPC A61K 31/02, A61P 11/00, A61M 16/00, publ. 10.12.2005).

The disadvantages of this method

1. There are no experimental developments to assess the effectiveness of the method.

2. Conclusions on the effectiveness of the method for the correction of acute lung injury are based on one case of a patient with acute lung injury syndrome, there are no statistics on the evaluation of this method.

3. The lack of effectiveness of the method in a critical condition of the patient - the effectiveness was revealed only for 13 days of mechanical ventilation after 64 sessions of inhalation of perfluorane, which is due to the lack of influence of perfluorocarbon on the state of the alveolar-capillary membrane, persistent pulmonary edema.

The technical result is to reduce mortality in acute lung damage by reducing the degree of hypoxemia, the area of infiltrative lung damage. In addition, the development of alveolar edema of the lung tissue is prevented and the degree of hemorrhagic soaking is reduced.

The essence of the invention lies in the fact that an hour after intratracheal administration of 0.03 ml of acetone, a combination solution containing 7.2% sodium chloride and 6% hydroxyethyl starch in distilled water in a volume of 4 ml / kg is administered once to rats.

The method is as follows. Acute lung damage is modeled by intratracheal administration of 0.03 ml of acetone to rats with urethane anesthesia. Pharmacological correction of acute lung injury syndrome is carried out by a single intravenous administration of a combined solution containing 7.2% sodium chloride, 6% hydroxyethyl starch in distilled water in a volume of 4 ml / kg, 1 hour after acetone aspiration.

Example 1

The experiments were carried out on 50 outbred rats of both sexes weighing 250-300 g, grown under vivarium conditions. The experiments were carried out in accordance with ethical standards and recommendations for the humanization of work with laboratory animals, as reflected in the "European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes" (Strasbourg, 1985). Maintenance and work with laboratory animals was carried out in accordance with the order of the Ministry of Health of the Russian Federation dated August 23, 2010 No. 708a "On approval of the rules of Laboratory practice." The study was approved by the Local Ethics Committee of the Mordovian State University named after P.P. Ogareva. "

Animals were divided into groups of 15 each. The 1st group consisted of intact rats, animals of the 2nd group (control) under urethane anesthesia simulated acute lung damage by intratracheal administration of 0.03 ml of acetone. The animals of the 3rd group, 1 hour after aspiration of iv / acetone, were administered a combined solution of 7.2% NaCl and 6% HES in a volume of 4 ml / kg. This combination solution corresponds in its pH 3.5 - 6 and theoretical osmolarity to 2464 mOsmol / l, a preparation for "low-volume resuscitation" of hyperXAES.

Most of the animals (75%) after aspiration of acetone were on their own breathing, the rest were transferred to mechanical ventilation (0.5 l / min, BH - 70 / min). Evaluation of the effectiveness of iv administration of a combined solution of 7.2% NaCl and 6% HES was carried out 1 hour after iv administration and after 1 day. For this, the saturation of arterial blood with oxygen was determined in animals using a pulse oximeter. Also studied parameters were: respiration rate (BH), expiratory volume, heart rate (HR), blood pressure (BP), which were determined using the BiopacSystems MP 150 experimental research system. The mortality rate in the experimental groups was determined one day after the simulation Nozzle The animals were killed 1 day after the modeling of SOPL under urethane anesthesia, the lungs were removed from the animals with the subsequent determination of their mass and area of damage. The lesion area was estimated by the number of lobes of the lungs that underwent infiltrative compaction. After extraction, the lungs were fixed in 10% neutral formalin, followed by preparation of histological preparations. Histological preparations were stained with hematoxylin and eosin. The significance of differences in the compared values was determined on the basis of t-student test. The differences were considered significant at p <0.05.

As our studies showed, all animals after 1 hour against the background of aspiration damage to the lungs showed hypoxemia, which was significantly corrected by iv administration of a solution of 7.2% NaCl and 6% HES, however, the oxygen saturation level of hemoglobin remained significantly lower than in intact animals ( table 1). Moreover, in the control group and the group using a solution of 7.2% NaCl and 6% HES, there was a decrease in expiratory volume, heart rate, and blood pressure in relation to the values of intact animals (p <0.05, Table 1). Mortality after 24 hours in the control group was 57.14%, and in the group using a solution of 7.2% NaCl and 6% HES - 22.2%. Blood oxygen saturation in the control group remained lower than in intact rats (p <0.05), and in the group where a solution of 7.2% NaCl and 6% HES was used after aspiration, the percentage of oxyhemoglobin was significantly higher than the control value and did not differed from that in intact animals (Table 2). The heart rate in animals that were injected with a solution of 7.2% NaCl and 6% HES was less than in animals of the control group (p <0.05, Table 2).

The number of affected lung lobes after 24 hours in the control group was 4.5 ± 0.19, which was significantly higher than after the introduction of the combined solution of 7.2% NaCl and 6% HES (1.58 ± 0.42).

In rat lung tissue 1 day after acetone aspiration, large focal hemorrhages are noted (Fig. 1). The interalveolar septa are sharply thickened (swollen), infiltrated with leukocytes (Fig. 1). The muscular wall of the arterioles is thickened. Red blood cells go beyond the lumen of the vessels. The airiness of the lungs is reduced, there are foci of distelectasis and atelectasis. The wall of the bronchi is not thickened. No inflammatory changes in the bronchial mucosa were detected. There are no exudation elements in the lumen.

In the group of animals in which the combined solution of 7.2% NaCl and 6% HES was used, there were no foci of hemorrhage and hemorrhagic impregnation. The interalveolar septa are thickened, but the degree of their leukocyte infiltration is much less pronounced than in the control. Red blood cells are not detected perivascular. The airiness of the lungs is preserved (Fig. 2). Foci of atelectasis are extremely rare. The clearance of the alveoli is clean. Epithelium of bronchioles, medium and large bronchi without signs of inflammation.

Thus, a single intravenous administration of a combined solution of 7.2% sodium chloride and 6% hydroxyethyl starch in distilled water in a volume of 4 ml / k with experimental syndrome of general lung damage after 1 hour from the moment of aspiration damage with acetone reduces the degree of hypoxemia, and after 1 day from moment of PLD reduces mortality, reduces the incidence of ARDS, reduces the degree of hypoxemia and reduces the area of infiltrative lung lesion. In addition, it prevents the development of alveolar edema of the lung tissue and reduces the degree of hemorrhagic impregnation.

Claims (1)

A method for the pharmacological correction of acute lung injury in an experiment, which consists in the fact that an hour after intratracheal administration of 0.03 ml of acetone, a combination solution containing 7.2% sodium chloride and 6% hydroxyethyl starch in distilled water is injected intravenously to rats in volume 4 ml / kg.

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