The influence of the peptide complex of pig kidneys on the free radical oxidation by experimental urolithiasis

The research objective was to study the influence of the peptide complex of pig kidneys on the free radical oxidation by experimental urolithiasis. The experiments were carried out on 35 outbred Wistar male rats weighing 200–250 g, divided into three groups: comparison group (11 intact rats); control group (12 rats), in which the animals received 1 % ethylene glycol solution during the period of 6 weeks; treatment group (12 rats), in which the animals received the injection of peptide complex of tissue material of pig kidneys in a dose of 15 mg. The peptide complex was received by means of acetic extraction from freeze-dehydrated homogenate of pig kidneys. After six weeks of the experiment the animals were euthanized according to the current ethical standards in order to study the activity of the free-radical oxidation (FRO) process in the kidneys, and also to carry the morphological research of the kidneys of the experimental animals. The activity of FRO process was calculated on the basis of the sum-total of the oxidant and antioxidant statuses. For this purpose the concentration of thiobarbituric reactive fatty acids oxidation products (TBRP), general pro-oxidant activity and the activity of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPO) were estimated. The morphological research of the rat kidneys was conducted using light-optical microscopy. As a result of modeling of urolithiasis the concentration of TBRP increased by 4.0 times in relation to healthy rats and the activity of GPO decreases by 1.9 times (for both – p < 0.0001). In the treatment group the concentration of TBRP decreased by 2 times in comparison with the control group (p < 0.001) and the activity of GPO increased by 246 % (p < 0.001). According to the results of morphometry the average area of the stones forming in the kidneys after the carried treatment decreased by 12.1 times: from 11.5 ± 1.7 mkm² in the control group to 0.95 ± 0.05 mkm² in the treatment group (p < 0.001). Therefore, the three-week intake of peptide complex of pig kidneys significantly weakens the oxidative stress in the kidney tissue of rats by experimental urolithiasis, which is accompanied by considerable size reduction of kidney stones.