Markers of oxidative and antioxidative activity in female dogs with mammary gland tumour with and without additional vitamin E supplementation

Renata Stavinohová,Ivana Borkovcová,Antonín Lojek,Jana Lorenzová,Michal Crha,Jakub Pfeifr,Ivana Papežíková,Markéta Mrázová

doi:10.2754/avb201281030275

Abstract

The present study determined markers of oxidative and antioxidative activity in dog females affected with mammary gland tumour compared to healthy ones. The effect of additional vitamin E supplementation on oxidative and antioxidative status was evaluated as well. The study included 29 female dogs divided into 4 groups (groups 1 and 2 included females with a mammary gland tumour; groups 3 and 4 included healthy female dogs). Additional vitamin supplement containing α-tocopherol was given to the females of groups 1 and 4. Dogs from groups 1 and 2 were anaesthetized before surgery (ovariohysterectomy and mastectomy); anaesthesia was used also in group 3, but without performeing surgery. The content of vitamin E (free α-tocopherol), marker of antioxidative status, was measured in blood serum by liquid chromatography. The concentration of thiobarbituric acid reactive substances, marker of oxidative status, in serum and concentrations of protein and non-protein thiol groups, markers of oxidative and antioxidative status, in blood serum and in red blood cells were measured colorimetrically. In females with a mammary gland tumour from group 2, concentration of thiobarbituric acid reactive substances was significantly higher than 14 days after surgery and compared to healthy ones as well. In females with a mammary gland tumour from group 2, concentration of protein thiol groups in serum was significantly lower and concentration of non-protein thiol groups in serum was significantly higher than in healthy controls. The values of protein thiols in erythrocytes in females with mammary gland tumour from group 1 were significantly higher before supplementation with vitamin E. The present study revealed that females with a mammary gland tumour were more burdened with oxidative stress compared to healthy dogs. The removal of the mammary gland tumour led to improvement of oxidative and antioxidative status. This is the first report focusing on the effect of additional α-tocopherol supplementation on reducing oxidative stress by increasing antioxidative activity in females affected with mammary gland tumour; however, we did not prove it.

Highlights

The present study revealed that females with a mammary gland tumour were more burdened with oxidative stress compared to healthy dogs
There was no significant difference in the concentrations of free α-tocopherol among the individual groups
Concentration of thiobarbituric acid substances in serum was higher in females of group 2 with mammary gland tumour (MGT) without vitamin E 10 days before the surgery than 14 days after the surgery

Summary

Introduction

Effects of vitamin E were studied in humans and in laboratory animals (Brigelius et al 2002; Shen et al 2009). Shen et al (2009) evaluated that vitamin E improved oxidative stress status and the metabolism of glucose and lipids. There are other studies evaluating the effect of vitamin E supplemented to healthy dogs and dogs before and after exercises (Scott et al 2001; Tran et al 2007). The aim of our study was to determine markers of oxidative and antioxidative activity in dog females affected with a mammary gland tumour compared to healthy ones. The effect of additional vitamin E supplementation on oxidative and antioxidative status was evaluated as well. We hypothesized that additional supplementation of vitamin E would reduce oxidative stress by increasing antioxidative activity in females affected with a mammary gland tumour

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Conclusion