ABSTRACT
<p><b>OBJECTIVE</b>To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.</p><p><b>METHODS</b>DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone (ranged from 10 micromol/L to 120 micromol/L) for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis (SCGE)] were performed respectively to detect the toxicity of hydroquinone.</p><p><b>RESULTS</b>MTT assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups.</p><p><b>CONCLUSIONS</b>Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.</p>
Subject(s)
Humans , Bronchi , Cell Biology , Cells, Cultured , Comet Assay , Cytotoxins , Toxicity , DNA Damage , DNA Polymerase beta , Physiology , Epithelial Cells , Cell Biology , Hydroquinones , Toxicity , RNA InterferenceABSTRACT
<p><b>OBJECTIVE</b>To study hPARP1 genetic polymorphism in southern Chinese Han and Miao populations.</p><p><b>METHODS</b>Blood samples from 187 and 210 southern healthy Han and Miao populations were collected. The mutations of exons 12,13,16 and 17 of hPARP1 gene were investigated by PCR-single-strand conformation polymorphism(SSCP).</p><p><b>RESULTS</b>Fragments of 253 bp,313 bp,175 bp,362 bp within exons 12,13,16 and 17 respectively of hPARP1 gene were amplified by multiple PCR. An SSCP variant in exons 12,13,16 and 17 of PARP1 gene in 187 healthy Han and 210 healthy Miao individuals was identified. Seven single-base substitutions compared with the sequence of PARP1 gene were identified: a T to C transition in exon 12 (Phe548Ser), a G to T transition in exon 13 (Ala683Ser), a G to T transition in exon 16 (Asp798Tyr), and a A to G transition in exon 17 (His808Arg).</p><p><b>CONCLUSION</b>There were polymorphism sites in exons 12,13,16,17 of hPARP1 gene in southern Chinese Han and Miao populations; these results may be useful for the establishment of PARP1 genotyping, and these newly described PARP1 alleles would be advantageous indicators for population studies.</p>
Subject(s)
Adult , Female , Humans , Male , Alleles , China , Exons , Genetics , Gene Frequency , Genotype , Poly (ADP-Ribose) Polymerase-1 , Poly(ADP-ribose) Polymerases , Genetics , Polymerase Chain Reaction , Polymorphism, Single Nucleotide , Genetics , Polymorphism, Single-Stranded ConformationalABSTRACT
<p><b>OBJECTIVE</b>To investigate whether or not adaptive response of hPARP-1 protein normal and deficient cells is induced by low dose of hydroquinone (HQ), and to analyze the relationship between the adaptive response and micronuclei formation, and cell cycle alteration in human embryo lung fibroblasts (HLF), so as to elucidate the mechanism of adaptive response.</p><p><b>METHODS</b>HLF, HLFC and HLFP cells pretreated with low concentration were retreated by high concentration of HQ. Cellular viability, the rate of micronuclei and abnormal nuclei, cell cycle and DNA strand break were determined.</p><p><b>RESULTS</b>The tolerance to 80.0 micromol/L concentration of HQ was enhanced when HLF, HLFC and HLFP cells were pretreated with HQ from 0.001 - 0.050 micromol/L. There were varying degrees of micronuclei and abnormal nuclei in three cells pretreated with low concentration of HQ and then retreated with high concentration of HQ; the cell numbers of G1, G2, S phase in cell cycle were obviously different. When compared with only high attack dose, the micronuclei rate and abnormal nuclei rate of HLF, HLFC and HLFP decreased by pretreatment with HQ at high concentration (P < 0.05), meanwhile increased by pretreatment with HQ at low concentration (P < 0.05). HLF, HLFC and HLFP showed blockage in G2 phase when pretreated with HQ at 0 approximately 0.05 micromol/L, but HLFP showed blockage in G1 phase, and in S phase at 1.0 and 2.0 micromol/L.</p><p><b>CONCLUSION</b>The level of adaptive response of hPARP-1 protein deficient cells was lower than normal cell, suggesting that hPARP-1 protein may play an important role in the adaptive response of cells, which may be related with the regulation of cell cycle.</p>