The 13th World Conference on Tobacco OR Health

Objective: The objective of the investigation is to make a comparative study of DNA repair systems in cell cultures of neuroblasts and fibroblasts, treated by synthetic analogue of carcinogen bez(á)piren. Polycyclic hydrocarbons (benz(á)pyren) are observed in the air due to the smoke and exhaust gases. They are dangerous for the whole population, especially for children and youth, and might be found in our food too. Revelation of peculiarities of DNA repair mechanisms is important for better understanding of genetic principles of carcinogenesis, aging, hereditary diseases, etc.

Methods: The molecular weight of DNA was determined by the method of sedimentation in alkaline gradient of sucrose.

Results: Postreplication repair (PRR) and replication “by pass” (RP) were investigated. It was shown that both cell lines were equal in their viability and there was no excision of carcinogen adducts. Mathematical analysis of experimental data indicated an exponential character of the PRR process. According to obtained results the mechanism of DNA RP differs principally from the mechanism of PRR and equal survivability of cells is achieved in different ways. We suppose that a long time (3 hours) after harmful impact, the genes in fibroblasts (but not in neuroblasts) are being activated which is necessary for free DNA synthesis “by pass”. We are living in more dangerous environment and we contribute to further contamination by our activities and life style The study of the above mechanisms and search for ways of making an influence on them is important for prevention of mutagenetic effects of environmental pollutants.