04586nas a2200433 a 4500 20260818095220.0 050929s2005 th uu|m rtt 0| a1eng d .b11971757 AIT Thesis no.EV-05-31 Gotovdorj, Tuvshinjargal Effects of cadmium on DNA damage and expression of repair gene Pathum Thani, Thailand : Asian Institute of Technology, 2005 64 leaves Thesis ; no. EV-05-31 Thesis (M.Sc.) - Asian Institute of Technology, 2005 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Inter-University Program on Environmental Toxicology, Technology and Management Cadmium is a highly toxic heavy metal; however it has been used worldwide. It has been classified a human carcinogen by IARC. Cadmium is genotoxic substance due to it can cause damage to DNA and chromosome. In this study, the effects of cadmium treatment on DNA damage and repair were studied in the human lymphocytes. The dose-response relationship between cadmium treatment and DNA strand breaks was studied in the human lymphocytes treated with 5, 10, 25, 50 and 100M cadmium. Using comet assay, the effects of cadmium treatment at various concentrations caused a significant induction of DNA strand breaks in a dose-dependent manner up to 50M and slightly increased further at 100M in the human lymphocytes. A The time-course of cadmium treatment on an induction of DNA strand breaks was carried out in lymphocytes treated with cadmium for 2, 4 and 24 hours. The effects of cadmium on the DNA strand breaks were also observed in the timedependent manner in the human lymphocytes. The induction of DNA strand breaks indicated a percentage of increase from control was highest at 4 hours following cadmium treatment at all test concentrations, and then dramatically decreased towards 24 hours of treatment. Cadmium treatment at 50M for 4 hours was then selected as the optimum dose and time of cadmium on the DNA damage. The effect of cadmium treatment on the oxidized base DNA damage was studied in human lymphocytes treated at 50M cadmium for 4 hours by comet assay with formamidopyrimidine-DNA-glycosylase (Fpg). The results showed that cadmium significant increased the Fpg-sensitive sites in the human lymphocytes by 1.4-fold (P<0.05), compared to control. Cadmium can cause oxidized base DNA damage. The alterations of repair gene (hOGG1) and metallothionein (MT) gene expression were studied in human lymphocytes treated with 50M cadmium for 4 hours by Reverse-Transcriptase and Polymerase Chain Reaction (RT-PCR). Cadmium induced MT mRNA expression by 1.62-fold (P<0.01) from control. In contrast, cadmium treatment resulted in decrease in the levels of hOGG1 by 1.67-fold (P<0.01), compared to control. In conclusion, the present study demonstrated that cadmium significantly increased DNA strand breaks in human lymphocytes in a dose and time-dependent. In addition, a significant increase in oxidized base damage indicated as Fpg-sensitive base was in accordance with the reduction of repair gene (hOGG1) in human lymphocytes treated with cadmium. Therefore, cadmium can cause genotoxic to human lymphocytes possibly by induction of oxidative DNA damage and of DNA repair inhibition. DNA damage DNA repair Cadmium Panida Navasumrit, Chairperson Preeda Pakpian, Examination Committee Piyajit Watcharasit, Examination committee Her Majesty The Queen of Thailand Asian Institute of Technology. Thesis ; no. EV-05-31 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B09401 .b11971757 mnait u 240329 0 050929 m a u 0 mnait mnait mnarc 20 40 Barcode : 30050004612114 CREATED : 2004-02-05 RECORD # : i1246126x LPATRON : 1017138 LCHKIN : 2004-09-12 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 1 TOT RENEW : 3 Barcode : 30050120737357 CREATED : 2004-02-05 RECORD # : i12461271 LPATRON : 1019610 LCHKIN : 2007-11-22 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 2 TOT RENEW : 2 Barcode : 30050160050505 CREATED : 2016-05-25 RECORD # : i12991533 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 35038 35038 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-05-31 30050004612114 2026-08-18 09:52:21 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-05-31 30050120737357 2026-08-18 09:52:21 2 2026-08-18 20 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.EV-05-31 30050160050505 2026-08-18 09:52:21 2026-08-18 40