The article deals with the question of determining the level of biochemical markers of blood (glycoproteins, chondroitinsulfates, total cholesterol, β-lipoproteins and glycosaminoglycan fractions) in rats for various variants of coagulation of the epidural vessels during surgical interventions on the lumbar spine. Material and methods. Experiment was carried out on 15 white laboratory male rats, aged 6 months with body weight of 250±30 g. All animals were given laminectomy at the lumbar level; the epidural bleeding was modeled by damaging the net of epidural vessels with an injection needle. In the 1st group (10 rats), we performed the electrocoagulation of the vessels of the epidural space in the lumbar spine (Martin diathermic coagulant, minimal mode of bipolar coagulation), in the 2nd experimental group (10 rats) we carried out the coagulation of the vessels of the epidural space using radio frequency coagulation (radiofrequency generator – Elliquence Surgi-Max, mode – bipolar / coag). Results and discussion. The control group of animals consisted of intact rats (n=5). The biochemical parameters of blood serum were changed to a greater extent in the group of rats of the 1st group, which carried out electrocoagulation of blood vessels in the epidural space. The average index of glycoprotein content was elevated in the 1st group for 30 days by 17.3 %, and by 7.9 % for 45 days compared with the indicator in intact animals. After 45 days of study, the content of glycoproteins was significantly higher in the 1st group than in the 2nd group. Indicators of chondroitin sulfates did not differ from the indicator in intact animals in both groups of animals and among themselves in all terms of observation, which is apparently due to the absence of damage to cartilage and bone tissue during the experiment. The content of total cholesterol and β-lipoproteins also had no significant difference in animal groups among themselves and compared to intact animals. The concentration of general GAG in serum did not differ among animal groups; however, a redistribution of their fractional composition with an increase in the III fraction was established. It was found out that in the 1st group of animals at days 30 and 45, the GAG fraction III was increased by 46.2 % and 19.20%, respectively, compared with intact animals. This, obviously, is due to damage to the vessels of the epidural space during electrocoagulation, because in the third fraction GAG contains predominantly heparan sulfate – a component of the vascular walls. In the 2nd group animals, the content of the III fraction (heparan sulfate) was not elevated compared to the indicator in intact animals, at 45 days it was significantly different from that in the 1st group and did not exceed the values in the intact group of animals. The content of hydroxyproline in the blood of the 1st group rats was higher than that of the 2nd group rats. The level of hydroxyproline in blood of the 1st group rats for 30 days was by 80.6 %, and for 45 days it increased twofold; in the 2nd group for 30 days it was by 43.7 %, for 45 days it increased by 35.2 % compared with the indicator in intact animals. Conclusion. This dynamics of the content of hydroxyproline, apparently, is due to a greater intensity of catabolism of collagen in the 1st group of animals, where vascular electrocoagulation was performed and, as a consequence, the development of epidural fibrosis. In the 2nd group where radiofrequency coagulation was used, the level of catabolism of collagen structures of the intervertebral discs was significantly lower, which was reflected in a lower level of hydroxyproline in the blood.
Keywords: rats, biochemical markers, lumbar spine, laser coagulation, radiofrequency ablation, epidural space, blood vessels
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