Oxidative stress and antioxidant in canine cutaneous mast cell tumors

Abstract

Oxidative stress can result from either the excessive production of reactive oxygen species (ROS) or an
impaired antioxidant system, or both. It causes damage to lipids, proteins and DNA. Therefore, oxidative stress may
be involved in carcinogenesis, and is associated with many types of cancer in dogs. The objective of this study was to
compare the levels of malondialdehyde, protein hydroperoxides, glutathione, retinol and alpha-tocopherol between
dogs with mast cell tumors and clinically healthy controls. Blood samples were obtained from eighteen clinically
healthy dogs and fourteen dogs with spontaneous mast cell tumors. Malondialdehyde and protein hydroperoxides
levels were measured by the thiobarbituric acid reactive substance assay, and the ferric-xylenol orange assay,
respectively. Glutathione level was determined using spectrophotometric assay. Retinol and alpha-tocopherol levels
were measured using the high performance liquid chromatographic method. Dogs with mast cell tumors had
significantly higher levels of malondialdehyde (P<0.01) and protein hydroperoxides (P<0.05) compared with the
clinically healthy controls. When considering antioxidants, dogs with mast cell tumors had significantly lower levels of
glutathione (P<0.01), retinol (P<0.05) and alpha-tocopherol (P<0.01) compared with the clinically healthy controls. Mast
cell tumors in dogs are associated with oxidative stress and antioxidant status. Further studies on oxidative stress and
antioxidant activity in dogs should be conducted to guide and plan the complementary treatment of canine cancer.