RU2440026C2 - Diagnostic technique for acute renal insufficiency in experimental - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention is related to experimental and clinical medicine, nephrology. In experiment the threefold bioimpedometry (BIM) of a renal cortex is conducted. The impedometry is held in the middle portion of the upper and lower pole of the kidney. An average value (Zav) is calculated. According to Zav, the presence or the absence of acute renal insufficiency is diagnosed.

EFFECT: method is simple, objective and allows reliably diagnosing acute renal insufficiency in experiment, also enabling the case follow-up.

2 tbl, 1 ex

Description

The invention relates to medicine and can be used in experimental medicine to detect acute renal failure in the experiment.

A known method for the diagnosis of acute renal failure in the experiment, in which the animal is decapitated, conduct a histological examination of the kidneys. The material is fixed with a 10% solution of neutral formalin, embedded in paraffin, ultrathin sections are prepared and stained with hematoxylin and eosin. Then, under the microscope, signs of acute renal failure are observed, such as the presence of enlarged glomeruli, in which, against the background of dissociation of the capillary segments, there were small hemorrhages in the loop, as well as swelling of the endothelium and mesangium. In this case, the tubules undergo granular or vacuole transformation with accumulation of protein casts in the expanded lumens. (Fidarova A.M. Functional and morphological features of experimental renal failure amid hypocalcemia. Abstract of the dissertation of Candidate of Medical Sciences. - Vladikavkaz. - 2008).

The method is time-consuming, and the assessment of the presence of acute renal failure is subjective and requires the removal of animals from the experiment, which makes it impossible to dynamically monitor the studied process.

The objective of the invention is the objectification of a method for the diagnosis of acute renal failure in an experiment with the aim of subsequent study of the nephroprotective properties of pharmacological preparations or substances without removing the animal from the experiment.

The essence of the proposed method is that through a laparotomy incision, bioimpedanceometry (BIM) of the renal cortex is performed in the region of the upper, lower poles and middle part, followed by the calculation of the average value (Z _cp ), and if Z _{cp is} less than 2.26 kOhm, then they say the presence of acute renal failure.

The measurement of the impedance of the kidney capsule in the region of the upper, lower poles and middle part is necessary in order to obtain objective information about the morphological and functional changes occurring in the kidneys in acute renal failure.

Experimentally, for 10 animals, we determined that the normal value of the impedance of the kidney in rats is in the range from 2.26 to 3.07 kOhm.

Example. A rat weighing 200 g was modeled for acute renal failure by the method of G. Greven (1981) by a single intramuscular injection of a 50% aqueous solution of glycerol at a dose of 0.8 ml per 100 g of weight.

On day 7, under ether anesthesia, a laparotomy was performed. Using needle electrodes, BIM (current frequency 20 kHz, voltage 1 V) of the cortical layer of the kidney was performed in the region of the middle part (Z ₂ ), lower (Z ₁ ) and upper (Z ₃ ) poles, for which electrodes from an inert metal were introduced into the tissue to a depth of 1 mm. Then calculated the average value (Z _cp ).

When measuring Z ₁ = 1.76 kOhm, Z ₂ = 1.48 kOhm, Z ₃ = 2.06 kOhm, then Z _cp = 1.77 kOhm, which is less than 2.26 kOhm, therefore, we can talk about the presence of acute renal insufficiency.

Further, the animal was decapitated, the kidneys were taken for histological examination. Microscopy revealed signs of acute renal failure: the presence of enlarged glomeruli, in which, against the background of dissociation of the capillary segments, there were small hemorrhages in the loop, swelling of the endothelium and mesangium, granular or vacuular transformation of the tubules with accumulation of protein casts in the expanded lumens, which confirmed the BIM data .

We performed experimental modeling of acute renal failure in 7 experimental animals (Wistar rats weighing 180-200 g) according to the method described above. All animals received BIM kidneys, the data are summarized in table 1.

In all rats, the average values of the impedance of the kidney were from 1.77 to 2.24 kΩ, i.e. less than 2.26 kΩ, and histological examination revealed signs of acute renal failure. The average group value of the impedance of the cortical layer of the kidney in animals with acute renal failure and intact animals, respectively, was 2.63 ± 0.097 kΩ and 2.06 ± 0.06 kΩ (p <0.001) (table 2).

Thus, the proposed method for the diagnosis of acute renal failure in the experiment is simple, objective, reliable, can be widely used in experimental medicine to study the nephroprotective properties of pharmacological preparations or to study the pathophysiological features of the process, and the method does not require animals to be taken out of the experiment.

Table 1 A method for the diagnosis of acute renal failure in the experiment Measurement number Impedance in the group of intact animals Z _cp (kOhm) (n = 9) Impedance in the group of animals with acute renal failure Z _cf (kOhm) (n = 7) one 2.73 1.77 2 2.63 2.19 3 3.07 2.16 four 2,35 2.24 5 2.42 2.11 6 2.76 1.97 7 3.03 2.15 8 2.26 9 2.41

table 2 Group of intact animals (M ± m) (n = 10) A group of animals with acute renal failure (M ± m) (n = 10) Group average impedance (kOhm) 2.63 ± 0.097 2.06 ± 0.06

Claims (1)

A method for diagnosing acute renal failure in an experiment by examining a kidney, characterized in that bioimpedanceometry (BIM) of the renal cortex is performed three times in the middle, upper and lower poles, and the average value (Z _cp ) is calculated, and if Z _{cp is} less than 2.26 kOhm , then talk about the presence of acute renal failure.