RU2497203C2 - Method of pharmacological correction of sceletal muscle ischemia with silnedafil including in l-name induced nitrogen oxide deficiency - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: calf muscle ischemia is simulated, including in a combination with additional simulation of nitrogen oxide deficiency by intraperitoneal introduction of the nitrogen oxide synthesis blocker N-nitro-L-arginine of methyl ester (L-NAME) 25 mg/kg daily for 7 days. In both cases, the ischemia is corrected by intragastric introduction of sildenafil 2.2 mg/kg on the first, third and fifth days of experiment.

EFFECT: significant improvement of microcirculation in the ischemic calf muscle of rats.

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Description

The invention relates to medicine, in particular to experimental pharmacology and surgery, and can be used to correct ischemia.

Closest to the claimed solution "Method for the correction of ischemia" proposed by M. Pokrovsky and other RU 2438192 C1. Where the correction of skeletal muscle ischemia is carried out by distant ischemic preconditioning, due to the stimulation of neoangiogenesis.

However, these decisions do not assess the effect of sildenafil on the state of the microvasculature in the ischemic skeletal muscle, including nitric oxide deficiency.

An advantage of the claimed method is that there is no ischemic episode, which is dangerous for various vascular pathologies. Activation of preconditioning mediators - nitric oxide and protein kinases, and the main effector link - ATP-dependent potassium channels is carried out by a pharmacological drug.

The technical result of the invention is the development of a method for pharmacological correction of skeletal muscle ischemia, including with L-NAME-induced deficiency of nitric oxide, including the use of sildenafil.

The technical result is achieved in that the correction of skeletal muscle ischemia, including when modeling nitric oxide deficiency by intraperitoneal administration to a laboratory animal for 7 days, nitric oxide synthesis blocker N-nitro-L-arginine methyl ester (L-NAME) at a dose of 25 mg / kg daily, carried out by intragastric administration of sildenafil at a dose of 2.2 mg / kg on the first, third and fifth days of the experiment.

The method is carried out as follows.

The experiments were carried out on white rats of the Wistar line weighing 220-250 g.

Nitric oxide deficiency is simulated by intraperitoneal administration to a laboratory animal of N-nitro-L-arginine methyl ether at a dose of 25 mg / kg daily for 7 days.

Acute ischemia is modeled on the muscles of the rat's right lower leg by operative removal of a section of the great vessels, including the femoral, popliteal, anterior and posterior tibial arteries.

The level of microcirculation in the calf muscles is determined using Biopac systems equipment: MP100 polygraph with laser Doppler flow meter LDF100C and invasive needle probe TSD144. Registration and processing of laser Doppler flowmetry (LDF) results is performed using the AcqKnowledge software version 3.8.1., Microcirculation values are expressed in perfusion units (PE). The microcirculation level is recorded at five points (the middle of the muscle length, points 3-5 mm above and below, lateral and medial of the first).

Microcirculation level is recorded in groups of mock-operated animals, with simulation of lower leg muscle ischemia, with simulation of lower leg muscle ischemia with L-NAME-induced nitric oxide deficiency and in animal groups that corrected lower leg muscle ischemia and lower leg muscle ischemia with L-NAME - induced deficiency of nitric oxide by sildenafil.

Sildenafil ("VIAGRA", Pfizer) is administered intragastrically at a dose of 2.2 mg / kg on the first, third and fifth days of the experiment.

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

EXAMPLE OF SPECIFIC PERFORMANCE

The average microcirculation level in the intact muscle of the tibia of rats is 526 ± 34 HE. Experimental animals were divided

into the following groups:

1) false-operated animals (n = 20);

2) modeling of ischemia of the leg muscles (n = 20);

3) modeling of ischemia of the leg muscles + sildenafil (n = 20);

4) modeling of ischemia of the leg muscles with L-NAME-induced nitric oxide deficiency (n = 20);

5) modeling of ischemia of the leg muscles with L-NAME-induced deficiency of nitric oxide + sildenafil (n = 20).

Ischemia of the muscles of the right tibia was simulated under anesthesia (chloral hydrate intraperitoneally 300 mg / kg of weight), by operative removal of a section of the great vessels, including the femoral, popliteal, anterior and posterior tibial arteries. Nitric oxide deficiency was modeled by animals of groups 4 and 5 by intraperitoneal administration of N-nitro-L-arginine methyl ether at a dose of 25 mg / kg daily for the first 7 days. Correction of muscle ischemia was carried out in animals of the 3rd and 5th groups by intragastric administration of sildenafil at a dose of 2.2 mg / kg on the first, third and fifth days of the experiment.

The microcirculation level in the calf muscles was determined using Biopac systems equipment: MP100 polygraph with laser Doppler flow meter LDF100C and invasive needle probe TSD144 on days 21 and 28. The registration and processing of laser Doppler flowmetry (LDF) results was performed using the AcqKnowledge software version 3.8.1., Microcirculation values were expressed in perfusion units (NOT). The microcirculation level curve was recorded at five points (the middle of the muscle length, points 3-5 mm above and below, lateral and medial of the first) for 30 seconds at each point. From the five values obtained, the average was deduced, which was entered into the protocol and was taken as the level of microcirculation in the calf muscles in this animal. From the 10 obtained values, the average was calculated, which was taken as the level of microcirculation in this group of animals at a given study period.

The results of assessing the level of microcirculation in animals of the experimental groups are presented in the table (table 1).

Table 1 The results of the assessment of the level of microcirculation in the tibial muscles of animals of the experimental groups (M ± m) in perfusion units 21 days (n = 10) 28 days (n + 10) False-operated animals 527 ± 10 532 ± 33 Shin Muscle Ischemia 322 ± 7 361 ± 8 Shin Muscle Ischemia + Sildenafil 435 ± 12 * 806 ± 42 * Shin Muscle Ischemia + L-NAME 351 ± 24 427 ± 13 Shin Muscle Ischemia + L-NAME + Sildenafil 359.93 ± 18.078 503 ± 24 ** Note. * - p <0.05 in comparison with a group of animals with ischemia of the calf muscles; ** - p <0.05 in comparison with a group of animals with ischemia of the calf muscles receiving L-NAME; sildenafil in a dose of 2.2 mg / kg on the first, third and fifth days of the experiment; L-NAME - N-nitro-L-arginine methyl ester daily intragastrically, at a dose of 25 mg / kg / day.

In the group of false-operated animals, the average value of the level of microcirculation in the muscles of the right tibia at all periods does not significantly differ from the indicators in the group of intact animals (526 ± 34 PE) (p = 0.19; p = 0.43, respectively). In the shin muscle ischemia modeling group, the microcirculation level at all periods was significantly lower than the value in the intact muscle (p <0.05).

Correction with sildenafil contributed to a significant increase in the level of regional blood flow in the ischemic muscle of the tibia of rats compared with the indicators in the second group at the corresponding time period (day 21 - p <0.05, day 28 - p <0.05). The level of microcirculation in this group on the 21st day approaches the indicator in the group of intact animals, and on the 28th day significantly exceeds it. When modeling shin muscle ischemia against the background of L-NAME-induced nitric oxide deficiency, the microcirculation level on day 21 in the treated group did not significantly differ from the group of animals not receiving treatment (p = 0.8229). A statistically significant difference was noted in these groups on day 28 (p <0.0002).

Thus, the obtained results allow us to ascertain the pharmacological correction of skeletal muscle ischemia with sildenafil, including with L-NAME-induced nitric oxide deficiency due to the stimulation of neoangiogenesis.

Claims (1)

A method for the pharmacological correction of skeletal muscle ischemia with sildenafil, including with L-NAME-induced nitric oxide deficiency, characterized in that the correction of skeletal muscle ischemia, including with modeling nitric oxide deficiency, by an intraperitoneal administration of a nitric oxide synthesis blocker to a laboratory animal for 7 days N-nitpo-L-arginine methyl ester at a dose of 25 mg / kg daily, is carried out by intragastric administration of sildenafil at a dose of 2.2 mg / kg on the first, third and fifth days of the experiment.