Possible role of DNA polymerase beta in protecting human bronchial epithelial cells against cytotoxicity of hydroquinone / 生物医学与环境科学（英文）

<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>

The therapeutic effects of low frequency ultrasound enhanced thrombolysis on acute cerebral infarction in rats / 中华物理医学与康复杂志

Objective To observe the therapeutic effects of low frequency ultrasound enhanced thrombolysis (LFUET) on acute cerebral infarction (ACI) in rats.Methods The ACI animal models were established by injec- ting auto-thrombus into the rats' left middle cerebral arteries.They were then treated with urokinase,and received transcranial LFUET treatment at the same time.Nervous system functioning was assessed using NSS,and infarct vol- umes (IVs) were measured through tetrazolium chloride (TTC) staining.Results The NSS scores in the large- dose urokinase group (LDU group),the ultrasound plus small-dose urokinase group (USMU group) and in the in- farct group (Ⅰgroup) at 24 h after treatment were significantly lower than those before treatment.IVs in the two treat- ment groups are lower than those in theⅠgroup,but there was no significant difference between the LDU group and USMU group volumes.Conclusion LFUET can accelerate the recovery of nervous system function in rats after ACI,minimize IVs,and reduce the required dosage of urokinase.