Diurnal rhythmicity of thiobarbituric acid reactive substances and antioxidants in experimental mammary carcinogenesis.

AIM

Circadian rhythms of reactive oxygen species and antioxidants have been the subject of considerable interest in recent years due to their crucial role in the development of malignant tumors. Our aim was to analyze the circadian pattern of lipid peroxidation by-products (TBARS) and antioxidants status in 7,12-dimethylbenz(a)anthracene (DMBA) induced rat mammary carcinogenesis.

METHODS

Mammary tumors were developed in Wistar rats, blood samples were collected at a regular interval of 4 h throughout the 24 h period and TBARS content and antioxidant enzymes activities (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)) were estimated by colorimetric methods. The Cosinorwin computer software program was used to analyze the characteristics of biochemical rhythms.

RESULTS

In mammary carcinogenesis, the acrophase of thiobarbituric acid reactive substances and antioxidant enzymes (SOD, CAT, GPx) in blood were found to be delayed, whilst mesor values for TBARS level - increased, and values for SOD, CAT, GPx activities - decreased. Significant r-values indicate the disruption of lipid peroxidation-antioxidants rhythms in mammary carcinogenesis.

CONCLUSION

The present investigation suggests that the circadian pattern of blood lipid peroxidation and antioxidants in rats with mammary carcinoma are markedly desynchronized as compared to normal rats.