RU2518127C2 - Method for modelling encopresis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine and biology, namely to proctology and may be used for modelling encopresis. One week prior to an encopresis modelling surgery, an animal intakes papaverine solution min. 40 ml - 2% papaverine hydrochloride 1 ml in physiologic saline 100 ml. Three days prior to the surgery, solid food is excluded, papaverine is withdrawn, and water is taken in an amount of 40 ml a day as a part of preparation for the surgery that involves a trapezoid exsection 1.5 cm deep of two fragments of anal soft tissues 15-17% of the rectal circumference at 4 and 8 o'clock of an imaginary clock-face; a standard diet is prescribed 3 days after the surgery.

EFFECT: method provides modelling a stable condition of encopresis closest to the clinically widespread one.

Description

The invention relates to medicine and biology, namely to proctology. Encopresis is currently a fairly common condition associated with fecal incontinence, developing due to weakness of the anal sphincter. To test the effectiveness of various approaches to the correction of encopresis in an experiment, it is necessary to develop a method for creating a stable model of this state, which allows reproducing it in 100% of cases with the complete exclusion of the possibility of spontaneous cure of this condition.

The closest analogue of the claimed method is (Kulikov D.A. Correction of functional and organic defects with age-related involution of the thymus, experimental diabetes mellitus, encopresis by transplantation of allogeneic tissues // Abstract for the degree of candidate of medical sciences, Moscow. - 2011. - 23 p. ) In the prototype, an rat encopresis model is created by wedge-shaped excision of a portion of the rectum of 25% of the total intestinal circumference with capture of the muscles of the external sphincter, tissue excision depth of 1.0-1.5 cm without subsequent suturing of the surgical wound (figure 1). To reduce the risk of infection of the wound surface in animals within 2 days after the operation, the amount of feces was reduced, depriving them of normal food 2 days before and 2 days after the operation, placing them on a glucose diet (10% glucose as a drink). When performing this model of encopresis, it is possible, without reducing the viability of animals, to remove only 25% of the circumference of the intestine and muscles of the external anal sphincter, which does not fully simulate the clinical situation that occurs during encopresis, when the more significant volume of the defect of the anal muscles is most often encountered. Another significant drawback of the model created in the prototype is the possibility in some cases of spontaneous cure of the animal without the use of any special corrective actions.

The aim of the invention, which coincides with its technical result, is to develop a method for creating a stable and closest to the prevailing clinic situation model of encopresis.

The essence of the claimed method is to prepare the animal for the operation to create an encopresis, starting to evaporate the papaverine solution, depriving them 3 days before the operation of solid food with the cessation of drinking papaverine and transferring them only to water. The operation is performed under local novocaine anesthesia with ophthalmic straight pointed scissors by excision of two trapezoidal fragments of soft tissues of the anal area at 15-17% of the circumference of the rectum for 4 and 8 hours on an “imaginary dial”, 1.5 cm deep. The animals are returned to the standard diet 3 days after surgery.

The claimed method is as follows.

A week before the operation to create an encopresis situation, animals (rats) prepared for the operation, to reduce the intestinal evacuation activity and create conditions for delaying stool in it, and weakening the anal sphincter muscles remaining after the operation and better modeling of the encopresis, should drink at least 40 ml / day papaverine solution (1 ml of a 2% solution of papaverine in 100 ml of physiological saline). 3 days before the operation, animals are deprived of solid food, papaverine is stopped and only one water of 40 ml per day is fed to each rat. Animals are returned to a standard diet 3 days after surgery, thereby ensuring that they do not have a bowel movement within 3 days before and 3-4 days after surgery.

The operation is as follows. The animal behind the limbs is fixed to the operating site using bandage (gauze dressings). Soft tissues infiltrate soft tissue to a depth of at least 1.5 cm with a 0.5% solution of novocaine paraanally with an insulin syringe (total anesthetic volume is 0.3 ml). Then, under sterile conditions, with the help of eye straight pointed scissors, trapezoidal excision of two fragments of soft tissues of the anal area is carried out at 15-17% of the circumference of the rectum (for 4 and 8 hours on the “imaginary dial”) with the capture of the muscles of the external anal sphincter. The depth of excision is 1.5 cm (figure 2).

The method allows to achieve a stable, reproducible in 100% of cases, model of encopresis, fully consistent with the most common clinical situation. This model allows you to test the effectiveness of various options for surgical and therapeutic approaches to the treatment of encopresis.

After the operation, the animal is placed back into the cage. Conduct daily visual monitoring of the state of the wound surface, tracking the occurrence of an act of defecation.

Example 1. A male Wistar rat, weighing 230 g, 05/04/2012 transferred to the evaporation of a solution of papaverine (1 ml of a 2% solution of papaverine in 100 ml of saline), which helped to reduce the intestinal evacuation activity, weakening the muscles of the anal sphincter and creating conditions for delaying feces. On 05/08/2012, the animal was deprived of solid food, papaverine was stopped and given 40 ml per day with water alone.

05/11/2012 the animal was operated according to the previously described scheme. 05/14/2012 the animal was transferred to a standard diet. 05/15/2012 - the first act of defecation. Due to dysfunction of the obturator apparatus of the rectum, feces were allocated only in the form of unformed mass. Complete epithelialization of the wound surface developed by 19 days after surgery.

Example 2. A male Wistar rat, weighing 215 g, 05/11/2012 transferred to the evaporation of a solution of papaverine (1 ml of a 2% solution of papaverine in 100 ml of physiological saline), which reduced the intestinal evacuation activity, weakened the muscles of the anal sphincter, creating conditions to delay feces. On May 15, 2012, the animals were deprived of solid food, they stopped giving papaverine and began to drink 40 ml per day with water alone.

05/18/2012 the animal was operated according to the previously described scheme. 05/21/2012 the animal was transferred to a standard diet. 05.21.2012 - the first act of defecation. As a result of dysfunction of the obturator apparatus of the rectum, feces were allocated only in the form of unformed mass. Complete epithelialization of the wound surface developed by 21 days after surgery.

Using the proposed method for creating an encopresis model allows you to achieve a stable, reproducible in 100% of cases and very close to the most common clinical picture of the state of fecal incontinence. This model can be used to evaluate various options for the correction of encopresis in the laboratory.

Claims (1)

A method of creating an encopresis model, characterized in that at least 40 ml of a papaverine solution of 1 ml of a 2% solution of papaverine in 100 ml of physiological saline are fed a day a week before the operation to create an encopresis, animals are deprived of solid food 3 days before the intervention, stop giving papaverine and drink 40 ml of water per day, preparing for the operation, consisting in a trapezoidal excision of 1.5 cm deep of two fragments of soft tissues of the anal region with a size of 15-17% of the circumference of the rectum at 4 and 8 hours according to the "imaginary dial"When the return of the animals on the standard diet after 3 days after surgery.

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