RU2466753C1 - Method for anaesthetisation in rats at staged experiment in simulated endometriosis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: what is involved is preanesthetic medication with xylazine. The preparation 'Zoletil 50' 0.5 mg/kg of rat's body weight is introduced intramuscularly for conducting main anaesthesia.

EFFECT: method provides adequate anaesthesia with simultaneous reduction of time of postanesthetic recovery that reduces the possibility of developing postoperative complications.

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Description

The invention relates to medicine and can be used in experimental studies for administration in anesthesia.

Known methods for the introduction into anesthesia of experimental animals using narcotic analgesics (morphine, promedol), antipsychotics (droperidol), antihistamines (diphenhydramine, suprastin), anticholinergics (atropine) used in doses: morphine 0.5 ml / kg body weight 1% solution; droperidol - 0.5 mg / kg body weight of 0.25% solution; diphenhydramine 1.5 mg / kg body weight of 1% solution; atropine 0.0001 / 10 kg / body weight of a 0.1% solution (Shalimov S.A., Radzikhovsky A.P., Keisevich L.V. Guide to experimental surgery, - M .: Medicine, 1989, p.153- 156. S.A.Shalimov, V.P. Radzikhovsky, L.V. Keysevich "Guide to experimental surgery." M: Medicine, 1989 R.S. Satoskar, S.D. Bandarkar, "Pharmacology and Pharmacotherapy ", M.: Medicine, 1986, I.S. Chekman, A.P. Peleshchuk, O.A. Pyatak" Guide to clinical pharmacology and pharmacotherapy. "Kiev," Health "1986).

However, the drugs and their combinations used for introducing into anesthesia have a number of disadvantages, namely: depress breathing and sometimes cause it to stop before the development of surgical anesthesia; they cause depression of the vasomotor center and slow down the way out of anesthesia, because their clinical effects last for 3-6 hours; enhance the gag reflex and have antidiuretic properties; are strictly accounting drugs, which limits their use; incompatible with barbiturates due to severe respiratory failure; in dogs, they promote dehydration, the development of metabolic acidosis, hemodynamic instability with a tendency to hypotension (S.A.Shalimov, A.P. Radzikhovsky, L.V. Keysevich "Guide to experimental surgery." - M .: Medicine, 1989) .

In a physiological animal experiment, a longer intravenous anesthesia (chloralose, numal, dial) is widely used. These substances, having a different chemical composition, act for several hours and allow for long-term operations and many hours of research on a living organism. Particularly widely used in animal experiments, chloralose (or chloralosan) (Kassil G.N. Science of pain. - M .: Medicine, 1975). The disadvantages of such anesthesia are the difficulty of getting experimental animals weighing (for example, rats with a live weight of 150-200 g), prolonged withdrawal from anesthesia, increasing the likelihood of serious complications leading to death, etc.

There is a method of anesthesia in an animal experiment, which consists in conducting premedication, induction and basic anesthesia, while the experimental animal is sequentially injected intramuscularly with a drug mixture of the following composition: droperidol, diphenhydramine, atropine, ketalar in therapeutic doses; then intramuscularly Relanium at a dose of 0.002-0.005 mg / kg body weight, 100 mg Tramal, after which Ketalar is administered at a dose of 1-2 mg / kg body weight and a 5% solution of Thiopental-Na in a dose intrapleurally, with an interval of 3-4 minutes 3-5 mg / kg body weight (Pat. No. 2072872 of the Russian Federation. IPC ⁶ A61M 21/00. (Method for non-inhalation anesthesia in an animal experiment. / Dmitriev OV Publ. 02.10.1997). Disadvantages of this method : the need to use a large number of drugs, the negative effect of barbiturates on the body.Sodium thiopental - a preparation of the barbiturate series - about It possesses high toxicity and have a direct depressor effect on the respiratory center and the cardiovascular system. The extent of these changes increases with depth of anesthesia (Bunyatyan AA Handbook of Anesthesiology and Intensive Care, Moscow, 1982, p.150).

It is known that Zoletil 50 is used for general anesthesia with premedication with vagolytic drugs (atropine), this is due to the need to block the influence of the vagus nerve on the cardiovascular system, otherwise there is a risk of vagus re-irritation during operations (especially abdominal ones), which can lead to cardiac arrest. When using the drug "Zoletil 50" it is also recommended to use atropine in a dose of 0.04 mg / kg. The disadvantages of this method: with an overdose of atropine, various neurological and somatic disorders can be observed. With intravenous administration of atropine, ventricular fibrillation of the heart may occur. (Instructions for the drug "Zoletil 50"). It is also known the use of the drug "Zoletil 50" with sedation xylazine. Xylazine (Xyla in 1 ml of the solution contains 20 mg xylazine hydrochloride) has a potential analgesic effect, followed by a dominant sedative effect. Depending on the dose, it causes CNS depression, reduces motor activity and often, in the first few minutes, ataxia is observed. The drug has a calming, analgesic, anesthetic and muscle relaxation effect. As a premedication before anesthesia, xylazine relieves muscle tension, and due to a sedative effect it softens the way out of anesthesia.

"Zoletil 50" is a preparation for general anesthesia containing tiletamine hydrochloride and zolazepam hydrochloride (125 mg of tiletamine hydrochloride and 125 mg of zolazepam hydrochloride as active substances). Tiletamin is a general anesthetic of dissociative action, causing a pronounced analgesic effect, but insufficient muscle relaxation. Tiletin does not suppress pharyngeal, larynx, cough reflexes, does not inhibit the respiratory system. Zolazepam inhibits the subcortical areas of the brain, causing anxiolytic and sedative effects, and relaxes striated muscles. Zolazepam enhances the anesthetic effect of tiletamine. It also prevents cramps caused by tiletamine, improves muscle relaxation and accelerates recovery from anesthesia. “Zoletil 50” is the latest generation of dissociatives, it is approved for use in the Russian Federation and is not included in the list of potent and psychotropic drugs due to the absence of a psychotropic effect, which allows the use of the drug “Zoletil 50” in veterinary medicine absolutely legally. "Zoletil 50" does not reduce body temperature, does not cause cardiorespiratory depression and does not have a toxic effect on the liver and kidneys, while maintaining laryngeal, pharyngeal and palpebral (blinking) reflexes, can be used in pregnant and newborn animals. Zoletil 50 can be combined with xylazine. Due to the fact that "Zoletil 50" has a pronounced analgesic effect when using sub-narcotic doses, xylazine is necessary as a muscle relaxant in order to achieve a sufficient depth of anesthesia. The combination of xylazine - "Zoletil 50" is synergistic. For combined anesthesia using Zoletil 50 and xylazine, the following dosages are recommended for dogs and cats: xylazine 0.05 ml / kg with i / m and iv once-only Zoletil 50 1-2 mg / kg (drug instruction "Zoletil 50"). Dosages for animals with low body weight are not indicated. This method is selected for the prototype. Its disadvantages are insufficiently quick exit from anesthesia (3-4 hours) for laboratory animals - female rats, the risk of complications in the postoperative period like pneumonia increases, which can result in death and loss of a laboratory animal for further experiment in modeling endometriosis.

The objective of the invention is to increase the survival of laboratory animals - rats in a long multi-stage experiment in modeling endometriosis.

The technical result is to reduce the time out of anesthesia of a laboratory animal - a rat, which reduces the likelihood of developing postoperative complications when modeling endometriosis.

This is achieved due to the fact that the drug "Zoletil 50" is administered at a dose of 0.5 mg / kg of rat body weight.

At the Department of Reproductive Medicine and Surgery, FPDO GOUVPO “Moscow State Medical-Dental University of the Ministry of Health and Social Development of the Russian Federation”, studies were conducted to create a model of experimental endometriosis. The disease was modeled by autotransplantation (endometrium into the peritoneum) of one endometrial fragment with myometrium (3 × 3 mm) obtained from the left uterine horn to the peritoneal surface of the anterior abdominal wall. All experiments were carried out in accordance with the requirements of the Geneva Convention "International Guiding Principles for Biomedical Research Involving Animals" (Geneva, 1990).

During the experiment, anesthesia was used according to the prototype method: for premedication, each female rat was injected intramuscularly with xylazine in a dose calculated according to the instructions in accordance with the weight of the animal, then “Zoletil 50” was also administered 10 minutes later, also in a dose calculated according to the instructions. However, during the time of recovery from anesthesia, which is 3-4 hours, in female rats in 5-10% of cases pneumonia developed and animals died, which negatively affected the receipt of statistically reliable data when monitoring the endometriosis focus. Empirically, gradually reducing the dose of Zoletil 50 administered and bringing it to half as compared with the initial 1 mg / kg body weight, the duration of anesthesia was 35-40 minutes, which was enough to conduct an operation to model experimental endometriosis. A result was achieved in which the time out of anesthesia was halved, and the survival rate of laboratory animals — female rats — became almost 100% throughout the entire multi-stage experiment in modeling endometriosis: after the operation, the animals were kept in the vivarium for 4 weeks for implant engraftment after which they measured the size and morphological evaluation of the obtained implants, in addition, the animal underwent not one, but two or three stomach cutting, which is important for monitoring the focus of endometriosis under the impact of various tested therapeutic factors in the experiment.

The method is as follows:

15 minutes prior to the main anesthesia, xylazine (Xyla preparation) is administered intramuscularly to the rat in a dose of 0.05 ml / kg body weight (according to the instructions), then after 10 minutes Zoletil 50 is administered at a dose of 0.5 mg / kg body weight body.

Example.

Fifteen minutes before the main anesthesia, the female Wistar rat (Stolbovaya nursery wiring) weighing 210 grams, which is in the proestrus phase, was injected intramuscularly with xylazine (Xila drug) in a dose of 0.01 ml, and 10 minutes after sedation, they administered Zoletil 50 "in a dose of 0.105 mg. The duration of anesthesia was 35 minutes. The animal emerges from anesthesia for 98 minutes. After the operation, the rat was kept in the vivarium under conditions of regulated daylight hours (12 × 12 hours) and constant room temperature (23 ± 2 ° C) on a standard diet and free access to water for 4 weeks for implant engraftment, during a further experiment to the animal made 2 more gluttony. After the operations, the laboratory animal remained alive.

Claims (1)

The method of anesthesia in rats during a multi-stage experiment in modeling endometriosis, including premedication with xylazine and basic anesthesia with the Zoletil 50 drug intramuscularly, characterized in that the Zoletil 50 drug is administered at a dose of 0.5 mg / kg of rat body weight.