Applications of a novel assay to investigate variation in DNA repair in human populations.

The aim was to develop and optimise an assay for assessing DNA repair in human lymphocytes and to use this assay in population studies. DNA repair has not been studied extensively in human populations due to the difficulty of finding a suitable assay for its measurement. This thesis describes the development and optimisation of the in vitro DNA repair assay. Cultured CHO K1 cells, used as a substrate, were damaged oxidatively under controlled conditions. A human lymphocyte extract was incubated with the cultured cells and the first stage of DNA repair-incision was carried out, producing increased strand breaks over time. These breaks were measured over 10 min and an arbitrary unit of DNA repair was given as the difference in number of strand breaks over this time. This assay was used firstly to analyse effects of increasing antioxidant capacity, on DNA repair, by giving daily supplements of kiwifruits to volunteers. Results showed repair rates significantly increased after consumption (up to 70 %), accompanied by a decrease in H2O2-induced DNA strand breakage (up to 26 %) and a highly significant decrease (23-33 %) in endogenous oxidative DNA damage. The in vitro DNA repair assay was also employed to assess effects of age on DNA damage and repair, showing a significant increase (34 %) in repair rate with age that had not been reported previously, accompanied by a decrease in strand break damage after 70 yr of age. DNA repair and damage was also assessed in volunteers occupationally exposed to asbestos or mineral fibres. Repair rate was significantly higher in all workers and control subjects of the asbestos factory compared to the mineral fibre factories and a reduced repair rate was highlighted in workers exposed to rockwool fibres compared to controls. This novel assay seems reliable and reproducible, and its use has extended the understanding of DNA damage and repair.

Grantor dc:publisher.institution

Robert Gordon University

Year dc:date.issued

2006

Author dc:creator

• Humphreys, Vikki Leanne

Advisor dc:contributor.advisor

• B. Ratcliffe, A. Collins and S. Duthie

• DNA repair
• Human lymphocytes
• CHO K1 cells
• DNA strand breaks
• Antioxidant capacity
• Asbestos workers
• Mineral fibre workers

Language dc:language

en

Identifier

oai:rgu-repository.worktribe.com:2807417
https://doi.org/10.48526/rgu-wt-2807417

OAI identifier oai:identifier

oai:rgu-repository.worktribe.com:2807417