Antioxidant Status and Biomarkers of Oxidative Stress in Dogs with Lymphoma

Abstract

Background: Oxidative stress might play a role in carcinogenesis, as well as impacting morbidity and mortality of veterinary cancer patients. The purpose of this study was to evaluate antioxidant concentrations and biomarkers of oxidative stress in dogs with newly diagnosed lymphoma before treatment and once in remission, with comparison with healthy controls.Hypothesis: Dogs with lymphoma have increased oxidant and reduced antioxidant concentrations compared with healthy controls, and that these abnormalities normalize once remission is achieved.Animals: Seventeen dogs with lymphoma and 10 healthy controls. Methods: Prospective, observational study. Measures of oxidative stress [malondialdehyde and total isoprostanes (isoP)] and antioxidants [a-tocopherol, g-tocopherol, oxygen radical absorbance capacity (ORAC), and glutathione peroxidase (GSHPx)] were assessed in dogs with newly diagnosed lymphoma before treatment compared with healthy control dogs. The same parameters were measured in the dogs with lymphoma on week 7 of the chemotherapy protocol when all dogs were in remission.Results: At baseline, dogs with lymphoma had significantly lower a-tocopherol (P o.001) and g-tocopherol (P 5 .003) but higher GSHPx (P 5 .05), ORAC (P 5 .001), and isoP (P o .001) compared with healthy controls. In the dogs with lymphoma, a-tocopherol concentrations were higher (P 5 .005) and ascorbic acid were lower (P 5 .04) after treatment.Conclusions and Clinical Importance: Results suggest that dogs with lymphoma have alterations in oxidant and antioxidant concentrations and that the status of some of these biomarkers normalize after remission. Further studies are warranted to determine whether antioxidant interventions to correct these are beneficial in the treatment of canine lymphoma.

Plasma Total Antioxidant Capacity and Activities of Blood Glutathione Peroxidase and Superoxide Dismutase Determined in Healthy Dogs by Using Commercially Available Kits

“…Many modifi cations of the coupled assay have been published, and they vary in substrate concentrations, type of peroxide, presence of chelators and inhibitors, pH, and temperature [15]. The results of our study are in general agreement with the results of studies carried out by Plevnik Kapun et al [26], Winter et al [43] and Stowe et al [44], but are not comparable to others [37,51,52]. In all these studies, the activity of GSH-Px was determined in whole blood using assays based on the method of Paglia and Valentine [9].…”

“…Interestingly, FRAP values determined in army service patrol dogs [41] were in good agreement with TAC values determined in our study. As expected, our TAC results were not in accordance with the TAC values determined in dogs with ORAC (Oxygen Radical Absorbance Capacity) [42,43] or TRAP (Total Radical-Trapping Antioxidant Parameter) [44,45] methods due to the great difference in methodological principals.…”

Oxidative stress in cancer-bearing dogs assessed by measuring serum malondialdehyde

“…These alterations may result in cell degeneration and death causing aging [3], and play a significant role in the pathogenesis of many diseases, such as cardiovascular diseases, neuropathies, inflammatory diseases, acquired immune deficiency syndrome (AIDS), diabetes mellitus, renal diseases, and mammalian cancers [4-14]. In dogs, oxidative stress has been associated with carcinogenesis [15]. Cancer in dogs is a major cause of death [16-18] and in Thailand there appears to be an increase in the incidence of dog cancers, as the number of cancer-bearing dogs diagnosed at the Veterinary Teaching Hospital, Khon Kaen University, Thailand between January 2008 and December 2011, increased by more than 50% (data from the annual reports of the hospital).…”

Lipid peroxidation in female dogs bearing mammary gland carcinomas

“…In dogs, studies are scarce and controversial. While Kumaraguruparan et al (2005) observed higher TBARS levels in bitches bearing mammary adenocarcinomas relative to healthy females, other studies involving dogs with lymphomas (Winter et al, 2009) and mammary neoplasms (Szczubial et al, 2004) did not show significant differences compared to control animals. One problematic feature in these oncological studies that try to link lipid peroxidation and carcinogenesis in dogs refers to the fact that they often include animals bearing heterogeneous tumors within the experimental  Recebido em 25 de janeiro de 2017 Aceito em 27 de março de 2017 *Autor para correspondência (corresponding author) E-mail: bondan@uol.com.br groups and these tumors are all grouped together even presenting different stages of progression.…”