ABSTRACT
Reactive oxygen species (ROS) produced as a part of cellular metabolism can interact with biological macromolecules such as DNA, proteins and lipids and interfere with their normal functions, leading to the loss of cellular viability. ROS have been implicated in many pathophysiological conditions including cancer. In the present study, the damage caused by ROS and the effect of radiation in head and neck squamous cell carcinoma (HNSCC) patients were assessed in the erythrocytes by analyzing the superoxide dismutase (SOD) and catalase (CAT) activities, and levels of total thiols (T-SH) and malondialdehyde (MDA, a marker for lipid peroxidation). Blood samples were collected before the start of treatment and after the completion of radiotherapy. Both SOD and CAT activities were decreased in untreated patients, but elevated in patients after treatment. The T-SH levels were also depleted in untreated HNSCC patients, but elevated non-significantly after radiation therapy (p>0.05). The levels of MDA showed a significant increase in both untreated patients and after radiation therapy when compared with normal subjects (p<0.05). Thus, the present study indicated that the free radical-mediated damage was aggravated in untreated HNSCC patients, but the levels of antioxidants returned to baseline or nearly so after the treatment with radiation therapy.
Subject(s)
Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/radiotherapy , Free Radicals/metabolism , Head and Neck Neoplasms/metabolism , Head and Neck Neoplasms/radiotherapy , Oxidative Stress/radiation effects , Radiation Injuries/metabolism , Carcinoma, Squamous Cell/enzymology , Case-Control Studies , Catalase/metabolism , Head and Neck Neoplasms/enzymology , Humans , Male , Malondialdehyde/metabolism , Middle Aged , Sulfhydryl Compounds/metabolism , Superoxide Dismutase/metabolismABSTRACT
Oxidative stress, a consequence of an imbalance between the formation and inactivation of reactive oxygen species, may be involved in the pathogenesis of many diseases including cancer. To evaluate the magnitude of oxidative stress, a study on the plasma levels of superoxide dismutase, total thiols, ascorbic acid and malondialdehyde (MDA) has been done in head and neck squamous cell carcinoma patients before the start of any oncological treatment and compared with healthy controls. The specific activity of superoxide dismutase in cancer patients is decreased significantly when compared to the control (p < 0.05). The total thiol and ascorbic acid levels are significantly reduced (p < 0.005) whereas MDA levels are significantly increased in the patients (p < 0.00005). Our findings show that the oxidative stress is elevated in cancer patients as evidenced by elevated levels of lipid peroxidation products and depletion of enzymatic and non-enzymatic antioxidants.
