Quantitative assessment of DNA damage directly in lens epithelial cells from senile cataract patients

PURPOSE Most of the studies regarding DNA damage in lens epithelial cells (LECs) of cataract patients have been done on lymphocyte or human LECs cultures. Studies of DNA damage directly in LECs of cataract patients are scanty and, to our knowledge, neither photographic evidence nor has a quantitative assessment of DNA damage have been put forward. In our study, we assessed and quantified DNA damage directly in the LECs of senile cataract patients, right after cataract surgery. METHODS LECs were taken from different morphologic types of senile cataract patients after surgery and DNA damage was immediately assessed by comet assay. Quantitative assessment of DNA damage was conducted using CometScore ™ software. RESULTS There were no prominent comets in most of the LECs of the control subjects, but comets were found in cataractous LECs. DNA fragments in the tail of the comet gave smearing (not banded), which was indicative of chemical damage (i.e., not site specific). DNA damage in the LECs of cataract patients was highly significant (p<0.001). DNA damage in cortical cataracts was significant (p<0.01) when compared to that of nuclear or posterior subcapsular cataracts, but the DNA damage between nuclear and posterior subcapsular cataracts was not significant. Furthermore, we found disrupted nuclear membranes in some of the nuclei in LECs of patients, but not in the control subjects. CONCLUSIONS In senile cataract patients, LECs DNA was randomly damaged and this type of damage was possible by reactive oxygen species (ROS). The damage was found maximally in the cortical type of cataracts. Oxidative DNA damage of the LECs may be one of the etiology of senile cataractogenesis.