Expression of Peroxiredoxins and Pulmonary Surfactant Protein A Induced by Silica in Rat Lung Tissue / 生物医学与环境科学（英文）

Silicosis is one of the most serious occupational diseases in China and dates back to centuries ago. In this study, we successfully established a rat model of silicosis by intratracheal silica injection for 28 days and determined hydroxyproline levels to evaluate collagen metabolism in lung homogenates. Oxidative stress status was evaluated by detecting catalase and glutathione peroxidase activities. Expression levels of peroxiredoxins (Prx I and Prx VI) were detected by Western blotting. Pulmonary surfactant protein A (SP-A) levels in rat serum and lung tissue were analyzed by ELISA, and SP-A and Prx expression levels in lung tissues were detected by immunohistochemistry. The results suggest that Prx proteins may be involved in pulmonary fibrosis induced by silica. Downregulation of SP-A expression caused due to silica is an important factor in the occurrence and development of silicosis.

The change of pulmonary surfactant protein of rat following silica exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the change of lung surfactant protein (SP) A,B,C,D of rats following silica dust exposure in order to provide the evidences for the early diagnosis indices or therapy of silicosis.</p><p><b>METHODS</b>60 male SD rats were randomly divided into silica group, and corresponding controls group. Rats in silica group were administrated 1 ml silica solution by intratracheal instillation at dose of 50 mg/ml. Rats in control group were administrated the same amount saline. At 3rd, 7th, 14th, 21st, 28th after silica exposure, serum and bronchoalveolar lavage fluid (BALF) samples were obtained. The concentration of SP-A, SP-B, SP-C, SP-D in serum and BALF were measured by using enzyme immunoassay (ELISA). Meanwhile the levels of total anti-oxidative activity (T-AOC) and hydroxyproline (HYP) in lung tissue were also detected. The pathology of lung tissue was conducted.</p><p><b>RESULTS</b>Compared with control group, SP-A concentration in BALF of silica exposed rat for 3, 14, 21, 28d was significant lower and SP-D concentration in BALF of silica exposed rat for all time points was also lower. The differences were significant (P < 0.05). Meanwhile SP-B level in 7, 14, 21, 28 d silica exposed rats BALF and SP-C level in 14, 21, 28 d silica exposed rats markedly decreased (P < 0.05). In addition compared with control group, SP-A, SP-B and SP-C concentration in serum of silica exposed rat were higher when SP-A for 14, 21, 28 d silica exposure, SP-B for 7, 14, 21 d silica exposure and Sp-C for 7, 14, 21, 28 d exposure. And all difference were significant (P < 0.05). As silica exposure time increased, SP-C concentration in serum showed an increase trend, which showed a time-response relationship (r = 0.618, P = 0.042). However, SP-D concentration in serum of rat for 7, 14, 21, 28d silica exposure were significant lower than that of control group (P < 0.005). And there was a decrease trend with time point exposure regarding of SP-D (r = -0.731, P = 0.016). The HYP content in lung tissue of experiment rats increased at 3rd, 7th, 14th, 21st and 28th day time point and The T-AOC activity in lung tissue decrease at, 7th, 14th, 21st and 28th day time point. The differences were significant (P < 0.05). There was a positive correlation (P = 0.803, P = 0.045) between SP-C in BALF and HYP of silica exposed rats and a negative correlation between SP-D in BALF and HYP (r = -0.867, P = 0.033). No significant correlation were seen between SP-A, SP-B BALF and HYP (y = 0.416, P = 0.28; r = 0.592, P = 0.071). SP-C concentration in BALF and serum all showed an increased trend and a positive correlation was seen (r = 0.539, P = 0.046). The same decrease trend was seen between SP-D in BALF and serum and correlation value was 0.870 (P = 0.034).</p><p><b>CONCLUSION</b>The silica exposure did cause the change of SP content both in BALF and serum. The SP-C and SP-D content in serum might be served as an early effective biomarker of silicosis.</p>

Regulatory effect of GDNF on the proliferation and differentiation of mammalian spermatogonial stem cells / 中华男科学杂志

The glial cell-derived neurotrophic factor (GDNF) is a member of the transforming growth factor beta (Tgf-beta) superfamily, which is produced by Sertoli cells and plays an important role in the proliferation and differentiation of spermatogonial stem cells (SSC). The addition of proper amount of GDNF to the culture media can promote SSC proliferation in vitro. Besides, GDNF regulates the self-renewal and differentiation of SSCs through various signaling pathways. This review focuses on the effects of GDNF on the proliferation and differentiation of mammalian SSCs and GDNF-mediated signaling pathways.

Dynamic analysis of Ca2+ level during bovine oocytes maturation and early embryonic development

Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca2+ and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca2+ was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca2+ was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca2+ was present throughout the blastomere. In PA embryos, Ca2+ was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca2+ in the SCNT embryos. However, Ca2+ was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca2+ showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca2+ location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

Relationship between urinary 1-hydroxypyrene level and peripheral blood lymphocyte chromosomal damage among coke oven workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the urinary 1-hydroxypyrene level and cytokinesis-block micronucleus in peripheral blood lymphocyte in coke oven workers.</p><p><b>METHODS</b>One hundred and fifty-eight workers from a coke plant and 158 referents without occupational PAHs exposure were recruited in this study. Urnary level of 1-hydroxypyrene was measured by alkaline hydrolysis combined with high performance liquid chromatography as an internal exposure dose, and the chromosomal damage of peripheral blood lymphocyte were evaluated with cytokinesis-block micronucleus (CBMN) method. Personal information including occupational history, age, sex, smoking and alcohol drinking, was collected by questionnaire.</p><p><b>RESULTS</b>The lymphocyte chromosomal damage level expressed as frequency of CBMN in coke oven workers was significantly higher than that of controls (3.32 ± 2.90 vs 0.57 ± 0.88, P < 0.01) after adjusting for sex, age, smoking and alcohol drinking, and correlation between urinary 1-hydroxypyrene concentrations and frequency of CBMN was found (Spearman Partial correlation coefficient = 0.28, P < 0.05) in coke oven workers. Three hundreds and sixteen subjects were divided into three groups by their urine 1-hydroxypyrene level (expressed as 0.11 ∼ 0.70, 0.71 ∼ 4.09 and 4.10 ∼ 24.74 µmol/mol Cr). After adjusting for age, sex, smoking and alcohol drinking by multiple nonparametric analysis of covariance, the frequency of CBMN in the groups of 0.71 ∼ 4.09 and 4.10 ∼ 24.74 µmol/mol C were 1.89 ± 2.37 and 3.29 ± 2.36, significantly higher than that in the group of 0 ∼ 0.70 µmol/mol Cr (0.56 ± 0.89).</p><p><b>CONCLUSIONS</b>Under present PAHs exposure levels, the Cytokinesis-block micronucleus test could detect PAHs-induced genotoxicity in coke oven workers.</p>