RU2500040C1 - Method for combined tadalafil and l-norvaline correction of l-name induced nitrogen oxide deficiency in experiment - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: nitrogen oxide deficiency is simulated by the daily 7-day intraperitoneal introduction of N-nitro-L-arginine methyl ester 25 mg/kg into experimental Wistar male rats. The nitrogen oxide deficiency is corrected by the simultaneous 7-day intragastric introduction of a combination of tadalafil 0.09 mg/kg and L-norvaline 10 mg/kg once a day.

EFFECT: effective management of the nitrogen oxide deficiency stimulated as described above by the therapeutic combination of the preparations first identified to this effect.

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Description

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

Closest to the claimed solution is the "Method for the correction of endothelial dysfunction of tadalafil with L-NAME induced nitric oxide deficiency" (Patent for invention No. 2364395), which consists in the use of a selective tadalafil inhibitor of phosphodiesterase (PDE5) at a dose of 0.9 mg / kg to restore vasorelaxation function against the background of blockade of endothelial NO synthase.

The main disadvantage of this method is that monotherapy with tadalafil at a dose of 0.9 mg / kg is less safe from the point of view of side effects, and is also aimed at only one link in the pathogenetic mechanism of development of endothelial dysfunction - the activity of the NO / cGMP pathway. At the same time, the possibility of pharmacological effects on another point of application in the pathogenesis of endothelial dysfunction - blockade of the enzyme arginase, which reduces the bioavailability of nitric oxide, is not taken into account.

The technical result of the invention is a method for correcting L-NAME induced nitric oxide deficiency in vivo, comprising using a combination of tadalafil and L-norvaline.

The technical result is achieved by the fact that, against the background of modeling endothelial dysfunction in an experiment, an intraperitoneal injection of a blocker of NO synthesis of L-nitro-arginine-methyl ether (L-NAME) at a dose of 25 mg / kg is carried out intraperitoneally in a laboratory animal for 7 days and is corrected by intragastric administration of a small dose tadalafil 0.09 mg / kg and L-norvaline at a dose of 10 mg / kg once a day.

The method is carried out as follows.

The experiments were performed on white male Wistar rats weighing 250-300 g. N-nitro-L-arginine-methyl ether (L-NAME) was administered intraperitoneally at a dose of 25 mg / kg / day. On the 7th day from the start of the experiment, a catheter is inserted into the left carotid artery under anesthesia (etaminal sodium 50 mg / kg) 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 Biopac 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 nitroprusside (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 seconds 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 (SRAD) 53.9 ± 2.7 mm Hg, while during the first 2-3 seconds a sharp bradycardia developed up to 130-150 beats per minute. Recovery of blood pressure occurred on average for 42.2 ± 0.8 seconds 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 SBP to 55.7 ± 3.5 mm Hg. followed by complete recovery on average within 45.1 ± 1.0 sec. Blockade of NO synthase by means of prolonged, daily, for 7 days, intraperitoneal administration of L-NAME (N-nitro-L-arginine-methyl ether at a dose of 25 mg / kg) 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 up to 82.8 ± 6.6, CAP up to 92.1 ± 6.1 mm Hg) and NP (CAP up to 88.7 ± 4.7, DBP up to 50.8 ± 4.2 and CAP up to 63 , 4 ± 4.1 mm Hg) compared with intact animals.

The simultaneous administration of L-NAME and a combination of tadalafil (0.09 mg / kg with L-norvaline 10 mg / kg led to a decrease in the initial values of blood pressure (SBP - 174.4 ± 1.9, DBP - 111.2 ± 0.7 mmHg) (table 1).

Table 1 Dynamics of blood pressure and heart rate in modeling nitric oxide deficiency and correction of endothelial dysfunction with a combination of tadalafil with L-norvaline 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 (0.09 mg / kg) + L-norvaline (10 mg / kg) Source 174.4 ± 1.9 ** 111.2 ± 0.7 ** 449.1 ± 34.8 EZV with AH 72.6 ± 4.5 ** 51.5 ± 3.2 ** 444.2 ± 39.4 * ENZV with NP 93.9 ± 3.6 55.2 ± 3.6 467.5 ± 35.5 * * - 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 to the need to derive a special indicator characterizing the degree of endothelial dysfunction, which is the ratio of the area of the triangle over the trend of the reaction of restoration of blood pressure in response to the introduction of NP to the area of the triangle over the trend of the reaction of restoration of blood pressure in response to the introduction of AH.

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

Thus, to further evaluate the effect of AH and NP in ESV and ENZV, this ratio was used as an indicator of correction of nitric oxide deficiency. So in the group where, against the background of administration of an inhibitor of NO synthase L-NAME, a combination of tadalafil with L-norvaline was introduced, this ratio corresponded to a value of 1.8 ± 0.1, while the concentration of nitrite ions (NOx) increased to 4.8 ± 0.2 μM / L (table 2).

table 2 Indicators reflecting the correction of L-NAME-induced nitric oxide deficiency by the combined administration of L-norvaline and tadalafil Groups of animals Functional Tests The increase in the fall of the vascular reaction by SRAD (mm Hg) Vascular reaction time (sec.) The area of the vascular reaction (conventional units) NOx (μM / L) The ratio of the areas of the vascular reaction of AH kNP Intact OH 59.9 ± 2.9 42.2 ± 0.8 1268.0 ± 74.8 7.2 ± 0.6 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 * 2.3 ± 0.6 * 5.4 ± 0.6 * NP 98.0 ± 2.0 * 67.4 ± 1.4 * 3322.7 ± 116.7 * L-NAME + Tadalafil + L-Norvaline OH 87.0 ± 7.7 ** 30.2 ± 4.7 * 1205.7 ± 121.4 ** 4.8 ± 0.2 ** 1.8 ± 0.1 ** NP 69.0 ± 6.0 ** 62.0 ± 2.5 * 2128.1 ± 197.4 ** * - p <0.05 compared with the intact group, ** - p <0.05 compared with the L-NAME group

Thus, the results obtained allow us to establish an effective correction of L-NAME-induced nitric oxide deficiency by a combination of tadalafil and L-norvaline.

Claims (1)

A method for correcting L-NAME induced nitric oxide deficiency, characterized in that against the background of its modeling, Wistar male rats with induced nitric oxide deficiency are injected with tadalafil 0.09 mg / kg and L-norvaline 10 mg / kg daily for 7 days against white simulation of white rats .