Impacto da suplementação de vitamina C sobre níveis de peroxidação lipídica e glutationa reduzida em tecido hepático de camundongos com imunossupressão induzida por ciclofosfamida

Objective: To investigate the effects of vitamin C supplementation on the levels of lipid peroxidation and reduced glutathione in the liver tissue of mice immunosuppressed with cyclophosphamide. Methods: Thirty-two 45-day-old female Swiss mice were divided into four groups of eight animals each as follows: control (distilled water); vitamin C (50 mg/kg); cyclophosphamide (100 + 150 mg/kg); and treatment (vitamin C 50 mg/kg + cyclophosphamide 100 +150 mg/kg). The substances were provided intraperitoneally for six days, and on the seventh day, the mice were euthanized. The biochemical analyses of lipid peroxidation (quantification of thiobarbituric acid-reactive substances) and reduced glutathione (estimate of non-protein thiols) were performed on liver tissue. Results: Cyclophosphamide increased the levels of lipid peroxidation (p<0.0001). Significant changes were not found in the groups treated with vitamin C. Cyclophosphamide alone did not affect the levels of reduced glutathione. Compared with the control group, vitamin C reduced the levels of reduced glutathione in animals that received or not cyclophosphamide. Vitamin C interacted with cyclophosphamide, that is, the chemotherapeutic agent further decreased the lower levels of reduced glutathione secondary to vitamin C intake. Conclusion: Cyclophosphamide, in the study dosage and duration, was capable of inducing oxidative damage, verified by increased lipid peroxidation. A vitamin C dosage of 50mg/kg of body weight did not protect against the oxidative damage caused by the chemotherapeutic agent.