The Effect of Hyperbaric Oxygenation on the Circulation of Urea in Rats Following Experimental Partial Hepatectomy

Material and methods. The studies were performed on 75 white mature rats (females) weighing 180—220g. Partial hepatectomy was performed by resection of a part of the left lobe of the liver (15—20% of the organ weight). Hyperbaric oxygenation (HBO) was performed three times (3 ata, 50 min). The first, second and third sessions were performed 4—8 hours, 24 hours and 48 hours after the surgery, respectively. The urea level was determined in the tissues of visceral organs, as well as in arterial blood (aorta), portal blood, blood from renal and hepatic veins, bile from common bile duct, and in urine on the 1st, 4th and 11th days of posthyperoxic period (days 3, 7 and 14 post-surgery).

Results. Activation of the urea incretion from the operated liver to the bloodstream under hyperoxic conditions was accompanied by increased urea concentration in the arterial blood and excretion from the body with urine that was facilitated by the elimination of a stimulating effect of PHE on the reabsorption of urea in the kidneys by the HBO procedure. At the same time, the production of urea in the renal tissue was activated and further released to the circulation through the renal vein. Stimulation of the liver and intestinal urea circulation by HBO was accompanied by the preservation of the stimulating effect of PHE on its accumulation in duodenum and colon tissues. In the thyroid gland, spleen, heart, and lungs of operated rats, HBO activated the transition of the «arterial» urea from the free form to the bound one. Termination of HBO normalized the urea concentration in the arterial blood by the 11th day of the posthyperoxic period whereas urea continued to be accumulated the heart, spleen, lungs, and intestine. A preserved increased release of urea from the operated liver into the bloodstream after HBO was accompanied by partial retention in the hepatocytes of urea delivered via bloodstreem through the portal vein. On the 11th day after HBO, the repeated hyperoxic activation of the liver and intestinal urea circulation occured, as well as HBO-restored stimulation of its production in the kidneys resulted in urea release into the renal vein and excretion with urea.

Conclusion. HBO provides a correcting effect on alteration of circulating urea caused by PHE.

1. Leonov A.N. Hyperoxia. Adaptation. Sanogenesis. Voronezh: VGMA; 2006: 190. ISBN 5-91132-003-7. [In Russ.]

2. Savilov P.N. Effect of hyperbaric oxygenation on glutamine metabolism in damaged and intact lobes of the operated liver. Biomeditsinskaya Khimiya. 2004; 50 (2): 164-171. PMID: 15179823. [In Russ.]

3. Savilov P.N. Effect of hyperbaric oxygenation on metabolism of glutamine in the liver. Biomeditsinskaya Khimiya. 2014; 60 (3): 364-371. DOI: 10.18097/pbmc20146003364. PMID: 25019399. [In Russ.]

4. Kamyshnikov V.S. Pocket reference book of the medical doctor on laboratory diagnostics. 8-th ed. Moscow: MEDpress-inform; 2014: 400. ISBN 978-5-00030-142-5. [In Russ.]

5. Savilov P.N. Ammonia-neutralizing function of hepatocytes after experimental liver resection. Patologicheskaya Fiziologiya i Eksperimentalnaya Terapiya. 2002; 4: 11-13. PMID: 12638422. [In Russ.]

6. Savilov P.N. Urea formation in the after operational liver. Biomeditsinskaya Khimiya. 2016; 62 (1): 79-81. DOI: 10.18097/PBMC20166201079. PMID: 26973192. [In Russ.]

7. Savilov P.N., Aleinikova T.L. The kinetics of urea in the body after liver resection in the experiment. Obshchaya Reanimatologiya = General Reanimatology. 2016; 12 (5): 23-31. DOI: 10.15360/1813-9779-2016-5-23-31. [In Russ., In Engl.]

8. Savilov P.N., Leonov A.N., Yakovlev V.N. Role of hyperbaric oxygenation in the mechanism of ammonium detoxication in resection of the liver in the presence of chronic hepatitis. Anesteziologiya i Reanimatologiya. 1994; 6: 31-34. PMID: 7733476. [In Russ.]

9. Savilov P.N., Molchanov D.V., Yakovlev V.N. Impact of hyperbaric oxygenation on body glutamine kinetics in hepatic failure. Obshchaya Reanimatologiya = General Reanimatology. 2012; 8 (2): 20-27. DOI: 10.15360/1813-0779-2012-2-20. [In Russ., In Engl.]

10. Richterrich D. Clinical chemistry. N.Y.: Academia Press; 1962: 256.

11. Glanz S. Medico-biological statistics. Moscow: Praktika; 1998: 459. ISBN 5-89816-009-4. [In Russ.]

12. Efuni S.N. (ed.). Guidelines for hyperbaric oxygenation. Moscow: Meditsina Publishers; 1986: 415. [In Russ.]

13. Vladimirov Yu.A., Proskurina E.V. Lectures on medical biophysics. Moscow: Akademkniga; 2007: 432. ISBN 978-5-211-05328-1. [In Russ.]

14. Krichevskaya A.A., Lukash A.I., Bronovitskaya Z.G. Biochemical mechanisms of oxygen intoxication. Rostov-on-Don: RGU; 1980: 116. [In Russ.]

15. Krichevskaya A.A., Lukash A.I., Vnukov V.V., Dudkin S.I. Iron-containing plasma proteins and proteolytic activity in blood serum for hyperbaric oxygenation and urea protective action. Biologicheskie Nauki. 1986; 9: 30–36. [In Russ.]

16. Molchanov D.V., Savilov P.N. Renal mechanisms elimination of ammonia liver resections (experimental study). Rossiisky Vestnik Detskoi Khirurgii, Anesteziologii i Reanimatologii. 2013; 3 (3): 64-68. [In Russ.]

17. Savilov P.N., Molchanov D.V. Impact of hyperbaric oxygenation on renalammonia excretion during experimental liver resection. Obshchaya Reanimatologiya= General Reanimatology. 2015; 11 (2): 56-63. DOI: 10.15360/18139779201525663. [In Russ., In Engl.]

18. Chernysheva M.D., Malygin A.M., Fel V.Ya. Induction of arginase activity in the splenocytes of C3HA mice undergoing partial hepatectomy. Tsitologiya. 1985; 27 (2): 209 - 212. PMID: 3992661. [In Russ.]

19. Mansurova I.D., Kaletina L.G. Enzymogram of serum and distribution ofenzymes in hepatocyte structures. In: Blyuger A.F. (ed.). Success in hepatology.Issue #3. Riga: Zvaigzne; 1971: 80-94. [In Russ.]