RU2364395C1 - Method of tadalafil-based correction of endothelial dysfunction in l-name induced nitric oxide deficiency - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention concerns medicine, particularly to experimental cardiopharmacology and can be used for correction of endothelial dysfunction that is ensured by simulation thereof in experiment by daily intraperitoneal introduction to Wistar male rats within 7 days of N-nitro-L-arginine methyl ester in a dose 25 mg/kg. Degree of dysfunction development is estimated by relation of endothelium-independent to endothelium-dependent vasodilation. Correction of dysfunction is carried out by intragastric introduction of Tadalafil in a dose 0.9 mg/kg once a day.

EFFECT: method provides effective correction of endothelial dysfunction in specific simulation environment.

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Description

The invention relates to medicine, in particular to experimental cardiopharmacology.

Closest to the claimed solution is a method for the correction of endothelial dysfunction using sildenafil, related to selective phosphodiesterase inhibitors (PDE5) of long-acting, described by G. Rossoni, B. Manfredi et al. In the article "Sildenafil reduces L-NAME-induced severe hypertension and worsening of myocardial ischaemia-reperfusion damage in the rat ”, British Journal of Pharmacology, 2007, V.150, P.567-576”, which consists of using sildenafil to restore vasorelaxation function against endothelial NO synthase blockade.

The main disadvantage of this method is that sidenafil is a shorter-acting drug, less selective and less safe than a drug of the same group of tadalafil. Therefore, the results of the correction of endothelial dysfunction during damage in the L-arginine NO system, which is mainly associated with deficiency of endothelial NO synthase, with the help of sildenafil are unsatisfactory.

The technical result of the invention is a method for the correction of endothelial dysfunction with L-NAME-induced nitric oxide deficiency, including the use of tadalafil, which is a selective PDE5 inhibitor with a longer duration of action.

The technical result is achieved by the fact that, against the background of modeling endothelial dysfunction in an experiment, an intraperitoneal injection of 25 mg / kg NO L-nitro-arginine-methyl ester (L-NAME) synthesis blocker into the laboratory animal for 7 days is carried out and correction is carried out by intragastric administration of tadalafil at a dose of 0.9 mg / kg once a day.

The method is carried out as follows.

The experiments were carried out on white rats male Wistar line weighing 250-300 g. N-nitro-L-arginine methyl ether (L-NAME) was administered intraperitoneally at a dose of 25 mg / kg / day, at the same time, tadalafil was administered intragastrically at a dose of 0.9 mg / kg / day On the 8th day from the start of the experiment, under anesthesia (ethinal sodium 50 mg / kg), a catheter is inserted into the left carotid artery to record blood pressure (BP), bolus administration of pharmacological agents is carried out in the right femoral vein. Hemodynamic parameters: systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) are measured continuously using the sensor and the Bioshell computer program. Functional tests: endothelium-dependent vasodilation (ESV) - intravenous administration of acetylcholine (AH) at a dose of 40 μg / kg, endothelium-independent vasodilation (ENZV) - intravenous administration of sodium nitropruside (NP) at a dose of 30 μg / kg.

When statistical data processing was calculated, the average value, the standard deviation. Differences were considered significant at p <0.05.

EXAMPLE OF SPECIFIC PERFORMANCE

A bolus intravenous administration of AH for 3-5 s led to a sharp drop in blood pressure reaching a peak in intact animals for systolic pressure (SBP) 84.3 ± 4.4, for diastolic pressure (DBP) - 38.7 ± 2.8 and for average arterial pressure (SAR) 53.9 ± 2.7 mm Hg, while during the first 2-3 s a sharp bradycardia developed up to 130-150 beats per minute. Recovery of blood pressure occurred on average for 42.2 ± 0.8 s after normalization of the heart rhythm. ENZV was also characterized by a decrease in SBP to 83.0 ± 3.7, DBP to 42.1 ± 4.4 and SRAD to 55.7 ± 3.5 mm Hg. followed by complete recovery on average within 45.1 ± 1.0 s. Blockade of NO synthase by means of prolonged, daily, intraperitoneal administration of L-NAME (N-nitro-L-arginine methyl ester at a dose of 25 mg / kg) for 7 days caused arterial hypertension (SBP - 190.3 ± 6.7 , DBP - 145.0 ± 3.9, SAD - 160.1 ± 4.6 mm Hg) and led to a smaller decrease in blood pressure after administration of AH (SBP to 110.6 ± 5.2, DBP to 82 , 8 ± 6.6, SAD up to 92.1 ± 6.1 mm Hg) and NP (SAD up to 88.7 ± 4.7, DBP up to 50.8 ± 4.2 and SAS up to 63.4 ± 4.1 mmHg) compared with intact animals.

The simultaneous administration of L-NAME and tadalafil (0.9 mg / kg intragastrically) did not lead to a decrease in the initial values of blood pressure (CAD - 208.7 ± 10.2, DBP - 155.0 ± 9.6 mm Hg) (Table 1).

Table 1. Dynamics of blood pressure and heart rate in modeling nitric oxide deficiency and correction of endothelial dysfunction with tadalafil. Groups of animals Functional Tests GARDEN, mmHg DBP, mmHg Heart rate, beats in minutes Intact Source 137.7 ± 3.7 101.9 ± 4.3 420.0 ± 9.0 EZV with AH 84.3 ± 4.5 38.7 ± 2.8 416.0 ± 14.0 ENZV with NP 83.0 ± 3.7 42.1 ± 4.4 415.0 ± 10.0 Receiving L-NAME (25 mg / kg) Source 190.3 ± 6.7 * 145.0 ± 3.9 * 428.0 ± 11 EZV with AH 110.6 ± 5.2 * 82.8 ± 6.6 * 426.0 ± 14.0 ENZV with NP 88.7 ± 4.7 50.8 ± 4.2 426.0 ± 13.0 L-NAME (25 mg / kg) + tadalafil (0.9 mg / kg) Source 208.7 ± 10.2 155, ± 9.6 398.0 ± 10.0 ** EZV with AH 99.8 ± 6.5 ** 61.9 ± 5.5 ** 373.0 ± 7.7 ** ENZV with NP 96.8 ± 9.3 55.9 ± 5.4 400.0 ± 11.0 * - p <0.05 compared to the intact group, ** - p <0.05 compared to the L-NAME group

The fundamental difference in ESV and ENZV in intact animals and animals with the introduction of an inhibitor of NO synthase L-NAME naturally led us to the necessity of deriving a special indicator characterizing the degree of endothelial dysfunction, which is the ratio of the area of the triangle over the trend in the reaction of restoration of blood pressure in response to the introduction of NP to the area triangle above the trend of the reaction of restoration of blood pressure in response to the introduction of AH.

We calculated this ratio for each animal in the intact group and rats after modeling the blockade of NO synthase and obtained a difference of this indicator by a factor of 5 — 1.1 in intact animals and 5.4 in animals treated with L-NAME, respectively.

Thus, to further evaluate the effect of AH and NP in ESV and ENZV, we used this ratio as an indicator of correction of endothelial dysfunction. So, in the group where tadalafil was administered against the background of the administration of the N0 synthase inhibitor L-NAME, this ratio corresponded to a value of 1.9 ± 0.3 (table 2).

table 2 Indicators reflecting the correction of endothelial dysfunction on the background of the introduction of L-NAME tadalafil Groups of animals Functional Tests Fall increase
vascular reaction according to SRAD (mmHg) Vascular reaction time (s) The area of the vascular reaction (conventional units) Attitude
areas of the vascular reaction of AH kNP Intact OH 59.9 ± 2.9 42.2 ± 0.8 1268.0 ± 74.8 1.1 ± 0.1 NP 61.0 ± 3.0 45.1 ± 1.0 1375.3 ± 93.7 L-NAME OH 68.0 ± 4.1 * 20.0 ± 1.4 * 695.3 ± 87.6 * 5.4 ± 0.6 * NP 98.0 ± 2.0 * 67.4 ± 1.4 * 3322.7 ± 116.7 * L-NAME + Tadalafil (0.9 mg / kg) OH 97.7 ± 6.8 ** 41.1 ± 6.0 ** 1923.5 ± 202.0 ** 1.9 ± 0.3 ** NP 104.0 ± 7.8 66.6 ± 5.5 3457.7 ± 382.1 * - p <0.05 compared to the intact group, ** - p <0.05 compared to the L-NAME group

Thus, the results obtained allow us to ascertain the correction of endothelial dysfunction by tadalafil that occurs with L-NAME-induced nitric oxide deficiency.

Claims (1)

A method for the correction of endothelial dysfunction, characterized in that in an experiment in white rats, males of the Wistar strain with endothelial dysfunction, against the background of its simulation by intraperitoneal administration of an inhibitor of endothelial synthase N-nitro-L-arginine methyl ester at a dose of 25 mg / kg daily, for 7 days , assessing the degree of development of dysfunction in relation to the indices of endothelium-independent and endothelium-dependent vasodilation, tadalafil 0.9 mg / kg is administered intragastrically daily for 7 days.