Formaldehyde induces the bone marrow toxicity in mice by regulating the expression of Prx3 protein.

Formaldehyde (FA) is a ubiquitous toxic organic compound, and it has been regarded as a leukemogen. However, the mechanisms by which FA induces bone marrow toxicity remain unclear. The present study was aimed to examine the bone marrow toxicity caused by FA and the mechanism involving the expression changes of peroxiredoxin3 (Prx3) in this process. The mice were divided into four groups with 6 mice per group. Animals in the control group were exposed to ambient air and those in the FA groups to different concentrations of FA (20, 40, 80 mg/m(3)) for 15 days in the separate inhalation chambers, 2 h a day. At the end of the 15-day experimental period, all mice were killed. Bone marrow cells were obtained. The level of hydrogen peroxide (H2O2), the apoptosis rate, and the activities and protein expression levels of caspase-3 and caspase-9 were determined by biochemical assay, flow cytometry and immunohistochemistry, respectively; DNA damage and Prx3 expression levels were measured by single cell gel eletrophoresis immunohistochemistry and Western blotting, respectively. The results showed that the H2O2 level and cell apoptosis rate were significantly increased in FA groups relative to the control group. Caspase-3 and caspase-9 activities and their protein expression levels were markedly increased as well. Additionally, FA also increased the rate of DNA damage and the expression level of Prx3 compared with control group. Our study suggested that a certain concentration of FA causes the bone marrow toxicity by regulating the expression of Prx3.

[Low-dose radiation induces endoplasmic reticulum stress and activates PERK-CHOP signaling pathway in mouse testicular cells].

OBJECTIVE: To explore the correlation of low-dose radiation with endoplasmic reticulum stress and the activation of the PERK-CHOP signaling pathway in mouse testicular cells. METHODS: Healthy Kunming mice were randomly assigned to time-effect (0, 3, 6, 12 and 24 h of irradiation at 75 mGy) and dose-effect (12 h of irradiation at 0, 50, 75, 100 and 200 mGy) groups. The contents of H202 and MDA were measured by colorimetry with the agent kits, the expressions of GRP78, PERK and CHOP mRNA detected by quantitative RT-PCR, and the levels of GRP7B, PERK, phosphorylated PERK (pho-PERK) and CHOP proteins determined by Western blotting and image analysis. RESULTS: After whole-body irradiation of the mice with 75 mGy, the content of H2 02 in the testis tissue was increased with time prolongation, while that of MDA decreased slightly at 3 and 6 h and then increased with the lengthening of time, both increased significantly at 12 and 24 h as compared with those at 0 h (P < 0. 05, P < 0. 01). Apart from reduced levels of GRP78 mRNA at 3 and 24 h and GRP78 protein at 6 h after irradiation, significant increases were found in the mRNA expressions of GRP78 at 12 h, PERK at 3,6, 12 and 24 hand CHOP at 12 and 24 h (P < 0.05, P < 0.01), as well as in the protein levels of GRP78 at 12 and 24 h, pho-PERK at 3, 12 and 24 h and CHOP at 3, 6, 12 and 24 h in comparison with those at 0 h (P < 0. 05, P < 0. 01). No obvious regularity was observed in the change of the PERK protein expression. After 12 h of whole-body irradiation, the content of H202 was increased at 50, 75 and 100 mGy, but decreased slightly at 200 mGy, while that of MDA was increased with dose increasing, with significant increases in the content of H2 02 at 75 and 100 mCy and in that of MDA at 75, 100 and 200 mGy as compared with the 0 mGy group. Apart from the reduced levels of GRP78 mRNA at 50 and 200 mCy, significant increases were found in the mRNA expressions of PERK at 75, 100 and 200 mGy and CHOP at 50, 75, 100 and 200 (P c 0. 05, P < 0.01) as well as in the protein levels of GRP78 at 100 and 200 mGy, pho-PERK at 50, 100 and 200 mGy and CHOP at 50, 75, 100 and 200 mCy as compared with those at 0 mGy (P < 0. 05, P < 0. 01). There were differences in the changes of different protein expressions, but no obvious regularity was seen in the change of the PERK protein expression. CONCLUSION: Low-dose radiation can induce endoplasmic reticulum stress in mouse testicular cells, and activate the PERK-CHOP signaling pathway.

[Research advance in allelopathy effect and mechanism of terrestrial plants in inhibition of Microcystis aeruginosa.] / é™†ç”Ÿæ¤ç‰©åŒ–æ„ŸæŠ‘åˆ¶é“œç»¿å¾®å›Šè—»ä½œç”¨æ•ˆåº”åŠæœºåˆ¶ç ”ç©¶è¿›å±•.

The inhibition of algae reproduction and control of harmful algal bloom are the primary challenges in the ecological restoration of eutrophicated water. It is urgent to inhibit algae over-reproduction in green and effective ways, one of which is the use of plant allelopathic effect. How-ever, few study focused on allelochemicals of terrestrial plants. Here, we introduced inhibition of Microcystis aeruginosa over-reproduction by allelochemicals from three categories of terrestrial plants, including herbaceous plants (Compositae/Papaveraceae, Liliaceae, Graminaceae), woody plants, and Chinese medicine plants. The classification, separation and identification of alleloche-micals from terrestrial plants that could be used for the inhibition of M. aeruginosa were summarized. Finally, the allelopathic mechanism to inhibit M. aeruginosa was discussed in detail to support the development of algistat. We also proposed some suggestions for the further development of algistat.

Effect of endothelial progenitor cells derived from human umbilical cord blood on oxygen-induced retinopathy in mice by intravitreal transplantation.

AIM: To investigate the effect of endothelial progenitor cells (EPCs) labeled by carboxy fluorescein diacetate succinimidyl ester (CFSE) on murine oxygen-induced retinopathy (OIR) by intravitreal transplantation. METHODS: After isolated from human umbilical cord blood mononuclear cells, EPCs were cultivated and then labeled with CFSE in vitro. C57BL/6J mice were placed to 75% hyperoxia chamber from P7 to P12 to establish OIR model. At P12, OIR mice were intravitreally injected with 1 µL suspension contained 2×105 EPCs (EPCs group) or isometric phosphate buffered saline (PBS group). The contralateral eye of each mice received no injection (OIR group). Evans blue angiography and frozen section were examined to track the labeled cells in OIR group at P15 and P19. Using retina paraffin sections and adenosinediphos phatase staining at P12 and P19, the effect of EPCs on OIR mice was evaluated quantitatively and qualitatively. RESULTS: The retinas from EPCs group with less non-perfusion area and fewer peripheral tufts were observed at P19, comparing with that from PBS or OIR group. The retinopathy in EPCs group receded earlier with less non-ganglion cells and neovascular nuclei, together with relatively regular distribution. The counts of the neovascular nuclei at P19 were reduced by 44% or 45%, compared with those of OIR group or PBS group respectively. Three days after EPCs injection, a large number of EPCs appeared in the vitreous cavity and adhered to the retinal surface. While at one week, the cells gathered between the internal plexiform layer and the inner limiting membrane, and some EPCs appeared in retinal vessels. CONCLUSION: EPCs transplantation can participate in the reparative procedure of the neovascularization in OIR.

Inhaled formaldehyde induces bone marrow toxicity via oxidative stress in exposed mice.

Formaldehyde (FA) is an economically important chemical, and has been found to cause various types of toxic damage to the body. Formaldehyde-induced toxic damage involves reactive oxygen species (ROS) that trigger subsequent toxic effects and inflammatory responses, which may increase risk of cancer. Therefore, in the present study, we aimed to investigate the possible toxic mechanism in bone marrow caused by formaldehyde. In accordance with the principle of randomization, the mice were divided into four groups of 6 mice per group. One group was exposed to ambient air and the other three groups were exposed to different concentrations of formaldehyde (20, 40, 80 mg/m3) for 15 days in the respective inhalation chambers, 2h a day. At the end of the 15-day experimental period, all mice were killed. Bone marrow cells were obtained. Some of those were used for the determination of blood cell numbers, bone marrow karyote numbers, CFU-F, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content; others were used for the determination of mitochondrial membrane potential (MMP), cell cycle and Bcl-2, Bax, CytC protein expression. WBC and PLT numbers in median and high dose groups were obvious reduced, but there was no change on RBC numbers. There was also reduced numbers of bone marrow karyotes and CFU-F in the high dose group. SOD activity was decreased, but MDA content was increased. MMP and Bcl-2 expression were decreased with increasing formaldehyde concentration, while expression of Bax and Cyt C was increased. We also observed change in cell cycling, and found that there was S phase arrest in the high dose group. Our study suggested that a certain concentration of formaldehyde could have toxic effects on the hematopoietic system, with oxidative stress as a critical effect.