Glutathione peroxidase of blood of dogs and cats with mammary tumors

Abstract

For timely diagnostics and successful treatment of mammary tumors in human and animals a necessary search of compounds that can be the biomarkers of this disease is needed. The aim of our work was to measure the activity of glutathione peroxidase (GPx) in blood plasma and erythrocytes of dogs and cats with mammary tumors and healthy animals for establishment of intercommunication between enzyme's activity and tumors. For researches took away blood at three groups of animals: 1) four healthy females of dogs (Canis familiaris) – the German Shepherd dogs by age 3, 6, 7 and 7; 2) four females of dogs with mammary tumors – the Russian Spaniel dog by age 8, Boxer dog by age 9 and the German Shepherd crossbred dogs by age 11 and 12; 3) four females of cats (Felis catus) with mammary tumors – crossbred cats by age 6, 8 and 10 and the Persian crossbred cat by age 13. Activity of GPx was determined by decrease of reduced glutathione in a presence of hydrogen peroxide for time unit with a count on the gramme of protein in blood plasma, or haemoglobin in erythrocytes. In the sick dogs’ erythrocytes the activity of GPx presents 30.45 ± 3.08 mmol GSH/min×g haemoglobin and it is more than for the healthy animals of 27.84 ± 5.24 mmol GSH/min×g haemoglobin, these differences aren't statistically reliable however. This index is the highest for the sick German Shepherd crossbred dog aged 11 and presents 38.5 mmol GSH/min×g haemoglobin. In sick dogs’ activity of GPx in blood plasma is 7.45 ± 1.60 mmol GSH/min×g protein and it is statistically reliable less than the healthy animals of 12.77 ± 1.18 mmol GSH/min×g protein. This index is the lowest for the the 12 years old sick German Shepherd crossbred dog and it is 3.41 mmol GSH/min×g protein. In sick cats activity of GPx in erythrocytes is 41.57 ± 4.10 mmol GSH/min×g haemoglobin, and the greatest it is in the sick crossbred cat age 10 – 52.52 mmol GSH/min×g haemoglobin. The activity of the enzyme in blood plasma of sick cats is 11.58 ± 1.99 mmol GSH/min×g protein and this index is similar to the healthy dogs. Activity of GPx of the erythrocytes of dogs and blood plasma of cats with mammary tumors did not differ from healthy dogs. The activity of GPx of sick dogs only in blood plasma is less than in healthy ones. It can be the consequence of this “exhaustion” of the enzyme and its involving in the process of neutralizing of active forms of reactive oxygen species in those tissues of organism where oxidizing stress develops. Next to the study of expression on the future it is necessary to pay attention to the study of polymorphism of GPx.