OBJECTIVETo 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.

METHODSDNA 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.

RESULTSMTT 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.

CONCLUSIONSHydroquinone 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.

Bronchi ; cytology ; drug effects ; Cells, Cultured ; Comet Assay ; Cytotoxins ; toxicity ; DNA Damage ; DNA Polymerase beta ; antagonists & inhibitors ; physiology ; Epithelial Cells ; cytology ; drug effects ; Humans ; Hydroquinones ; toxicity ; RNA Interference

Vibrio vulnificus cytolysin (VVC) has been implicated as one of the important virulence determinants of V. vulnificus that causes serious septicemia and wound infection. An attempt was made to investigate that VVC could act as a ligand which stimulates intracellular signaling systems. Cholesterol dose-dependently blocked VVC hemolytic activity through oli-gomerization of cytolysin. Among cholesterol derivatives including 7-dehydrocholesterol, cholesteryl esters, deoxycholate, and cholestane tested, only 7-dehydrocholesterol induced oligomerization as well as inactivation of VVC. These results show that oligomerization of VVC is completely dependent on three-dimensional structure of cholesterol where specific interaction of cholesterol at oligomerization sites of VVC is very selective. These findings support the idea that cholesterol which constitute many of cellular plasma membrane could be a receptor of VVC on plasma membrane of target cells.
Animals ; Bacterial Toxins/antagonists & inhibitors/chemistry/metabolism ; Cholesterol/chemistry/*pharmacology ; Cytotoxins/antagonists & inhibitors/*chemistry/*metabolism ; Dehydrocholesterols/chemistry/pharmacology ; Dose-Response Relationship, Drug ; Erythrocytes/drug effects ; Hemolysis/drug effects ; Mice ; Molecular Structure ; Signal Transduction ; Substrate Specificity ; Vibrio/*chemistry

OBJECTIVETo study the effect of anticolchicine cytotoxicity of Dan Gua-Fang, a Chinesea Chinese), a Chinese herbal compound prescription on endothelial cells of vein (ECV304) cultivated in mediums of different glucose concentrations as well as the proliferation of those cells in the same conditions, in order to reveal the value of Dan Gua-Fang in preventing and treating endothelial damage caused by hyperglycemia in diabetes mellitus.

METHODSThe research was designed as three stages. The growing state and morphological changes were observed when ECV304 were cultivated in the culture mediums, which have different glucose concentrations with or without Dan Gua-Fang and at the same time with or without colchicine.

RESULTS(1) Dan Gua-Fang at all concentrations reduced the floating cell population of ECV304 cultivated in hyperglycemia mediums. (2) Dan Gua-Fang at all concentrations and hyperglycemia both had a function of promoting "pseudopod-like" structure formation in cultivated ECV304, but the function was not superimposed in mediums containing both hyperglycemia and Dan Gua-Fang. (3) Colchicine reduced and even vanished the "pseudopod-like" structure of the endotheliocyte apparently cultivated in mediums of hyperglycemia or with Dan Gua-Fang. The "pseudopod-like" structure of the endotheliocyte emerged quickly in Dan Gua-Fang groups after colchicine was removed, but it was not the case in hyperglycemia only without Dan Gua-Fang groups. (4) Dan Gua-Fang reduced the mortality of cells cultivated in mediums containing colchicine. The cell revived to its normal state fast after colchicine was removed.

CONCLUSIONDan Gua-Fang has the functions of promoting the formation of cytoskeleton and fighting against colchicine cytotoxicity.

Cell Culture Techniques ; Cell Line ; Cell Shape ; drug effects ; Colchicine ; adverse effects ; antagonists & inhibitors ; Culture Media ; adverse effects ; pharmacology ; Cytoprotection ; drug effects ; Cytotoxins ; adverse effects ; antagonists & inhibitors ; Drug Antagonism ; Drug Combinations ; Drug Evaluation, Preclinical ; Drug Synergism ; Drugs, Chinese Herbal ; adverse effects ; pharmacology ; Endothelial Cells ; drug effects ; physiology ; Glucose ; pharmacology ; Humans ; Umbilical Veins ; cytology ; drug effects ; Up-Regulation