In vitro study on role of Hsp70 expression in DNA damage of human embryonic lung cells exposed to Benzoapyrene / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown.</p><p><b>METHODS</b>We assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay).</p><p><b>RESULTS</b>Exposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent +-increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 micromol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells.</p><p><b>CONCLUSION</b>These data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.</p>

Effects of mitogen activated protein kinase signal transduction pathways on heat shock protein 70 gene expression in endothelial cells exposed to benzo(a)pryene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of mitogen activated protein kinase (MAPK) signal transduction pathways on heat shock protein 70 (HSP70) gene expression in endothelial cells exposed to benzo(a)pryene (BaP).</p><p><b>METHODS</b>Porcine aortic endothelial cells were pre-treated or by PD98059 (10 micro mol/L) or SB203580 (20 micro mol/L) for 1 hour, then treated with different concentrations of BaP (0, 0.1, 0.5, 1.0, 5.0 and 10.0 micro mol/L) for 24 hours respectively;Expression levels of three phosphorylated MAPKs [extracellular signal regulated protein kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38] and HSP70 were determined by Western-blot.</p><p><b>RESULTS</b>The three phosphorylated MAPKs expressional levels especially p-ERK1 had different extents of changes with dose-response relationship under BaP exposure. BaP inhibited the expression of HSP70, which significantly decreased in medium and high dose group (>or= 1.0 micro mol/L) but did not decrease in control group (P < 0.05). Although the inhibitor of ERK (PD98059) could partly weaken the inhibited effects of BaP on HSP70 expression, HSP70 expression levels of endothelial cells pre-treated with PD98059 were still significantly lower than that of control cells (P < 0.05).</p><p><b>CONCLUSION</b>ERK1 pathway might play some roles in HSP70 gene expression in endothelial cells exposed to BaP, and other unknown signal pathways might also have some effects on this process.</p>

Immunohistochemical method for the detecting expression of transforming growth factor-beta1 in lung tissues of silica-treated mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the protein expression of transforming growth factor-beta(1) (TGF-beta(1)) in lung tissues of silica-treated mice.</p><p><b>METHODS</b>The experimental mice were divided into control and silica groups. 0.2 g/kg body weight of silica was injected intratracheally in mice of silica group. Samples of lung tissue were collected 1, 3, 5, 7, 14 and 28 d after injection. The immunohistochemical method was used to analyze the protein expression of TGF-beta(1).</p><p><b>RESULTS</b>In control mice, the expression of TGF-beta(1) in lung tissue was slightly positive while it was markedly increased in silica-treated mice. The expression was significantly elevated from the 7th day to 14th day. The expression in alveolar macrophages reached the peak on the 5th day [(93.4% +/- 2.8%) vs (42.2% +/- 12.0%), P < 0.01].</p><p><b>CONCLUSION</b>TGF-beta(1) may play an important role in early development of silicosis.</p>

RT-PCR method for detecting the expression of transforming growth factor-beta1 gene in lung tissues of silica-treated mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the gene expression of transforming growth factor-beta(1) (TGF-beta(1)) in lung tissues of silica-treated mice.</p><p><b>METHODS</b>The experimental mice were divided into control and silica group. 0.2 g/kg body weight of silica was injected intratracheally in silica group. Samples of lung tissue were collected 1, 3, 5, 7, 14 and 28 d after injection. RT-PCR method was used to analyze the gene expression of TGF-beta(1) in lung tissue of silica-treated mice.</p><p><b>RESULTS</b>The expression of TGF-beta(1) gene in lung tissue elevated from the 3rd day (1.20 +/- 0.15) and the peak value was on the 7th day (1.74 +/- 0.19). Then the expression decreased from the 14th to 28th day. But there was still higher than control until the 28th day.</p><p><b>CONCLUSION</b>TGF-beta(1) may play an important role in silica-induced pulmonary fibrosis.</p>

The expression of cytochrome P450 1A1 of endothelial cells induced by benzo(a)pyrene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effect of benzo(a)pyrene (BaP) on the expression and the activities of cytochrome P450 1A1 (CYP1A1) of porcine aortic endothelial cells.</p><p><b>METHODS</b>Porcine aortic endothelial cells were cultured in vitro, and treated with different concentrations of BaP (0, 0.5, 1.0, 5.0, 10.0 micro mol/L) for 24 hours, CYP1A1 expression was determined by Western blot and immunohistochemistry. At the same time, the ethoxyresorufin-o-deethylase (EROD) activities were measured by spectrofluorometer.</p><p><b>RESULTS</b>By Western blot, the expression of CYP1A1 of control cells was not found, but the expression of CYP1A1 of cells treated with BaP was found; By immunohistochemistry, only part of endothelial cells treated with BaP had positive expression of CYP1A1. The peak activities of EROD induced by BaP was at the concentration of 0.5 - 1.0 micro mol/L.</p><p><b>CONCLUSION</b>BaP could induce part of endothelial cells to synthesize CYP1A1. BaP of 0.5 - 1.0 micro mol/L could induce peak activities of EROD.</p>