Effect of the chelator BPCBG on the decorporation of uranium in vivo and uranium-induced damage of human renal tubular epithelial cells in vitro / 药学学报

This study is to assess the efficacy of BPCBG on the decorporation of uranium (VI) and protecting human renal proximal tubular epithelial cells (HK-2) against uranium-induced damage. BPCBG at different doses was injected intramuscularly to male SD rats immediately after a single intraperitoneal injection of UO2(CH3COO)2. Twenty-four hours later uranium contents in urine, kidneys and femurs were measured by ICP-MS. After HK-2 cells were exposed to UO2(CH3COO)2 immediately or for 24 h followed by BPCBG treatment at different doses for another 24 or 48 h, the uranium contents in HK-2 cells were measured by ICP-MS, the cell survival was assayed by cell counting kit-8 assay, formation of micronuclei was determined by the cytokinesis-block (CB) micronucleus assay and the production of intracellular reactive oxygen species (ROS) was detected by 2',7'-dichlorofluorescin diacetate (DCFH-DA) oxidation. DTPA-CaNa3 was used as control. It was found that BPCBG at dosages of 60, 120, and 600 micromol kg(-1) resulted in 37%-61% increase in 24 h-urinary uranium excretion, and significantly decreased the amount of uranium retention in kidney and bone to 41%-31% and 86%-42% of uranium-treated group, respectively. After HK-2 cells that had been pre-treated with UO2(CH3COO)2 for 24 h were treated with the chelators for another 24 h, 55%-60% of the intracellular uranium was removed by 10-250 micromol L(-1) of BPCBG. Treatment of uranium-treated HK-2 cells with BPCBG significantly enhanced the cell survival, decreased the formation of micronuclei and inhibited the production of intracellular ROS. Although DTPA-CaNa3 markedly reduced the uranium retention in kidney of rats and HK-2 cells, its efficacy of uranium removal from body was significantly lower than that of BPCBG and it could not protect uranium-induced cell damage. It can be concluded that BPCBG effectively decorporated the uranium from UO2(CH3COO)2-treated rats and HK-2 cells, which was better than DTPA-CaNa3. It could also scavenge the uranium-induced intracellular ROS and protect against the uranium-induced cell damage. BPCBG is worth further investigation.

Reversion of multidrug resistance (MDR) in human glioma cells by RNA interference (RNAi) / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore whether the constructed vector of short haprin in vivo can induce human glioma cell line BT325 to produce RNAi duplexes and reverse the expression of MDR1 gene.</p><p><b>METHODS</b>Three 62nt oligonucleotide fragments (shRNA) were constructed according to GenBank MDR1 sequence and were cloned to the retrovirus-delivered vectors. After transfected these vectors directly into the human malignant glioma BT325 cells by lipofectamine 2000 with enhanced green fluorescence protein (EGFP) co-transfecting, the MDR1 gene silence effects were detected by the changing level of mRNA and P-glycoprotein including real time PCR (RT-PCR), Northern blot and Western blot analysis. To assess the multidrug resistance against adriamycin (ADR) and VCR, cell proliferation assays were performed by cell counting kit-8.</p><p><b>RESULTS</b>The RNAi plasmid vectors were constructed successfully. RT-PCR showed MDR1 mRNA was significantly reduced (P < 0.05). Northern blot analysis showed that the gene silence became most intense at 48 hours after transfection. Western blot analysis demonstrated that P-gp expression was reduced at different time to 12.9%, 30.3% and 4.8%, respectively. The chemosensitivity assays indicated that the transfected cells showed an enhanced sensitivity to ADR and VCR. Based on the value of IC(50), BT325 cells had significantly increased sensitivity to the drugs.</p><p><b>CONCLUSION</b>The sequence specific RNAi can inhibit MDR1 mRNA and P-gp expression in the glioma cell line. It may reverse multidrug resistance phenotype, therefore, may provide promising therapeutic modalities in the treatment of human glioma.</p>

Effect of rat Schwann cell secretion on proliferation and differentiation of human neural stem cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the effect of rat Schwann cell secretion on the proliferation and differentiation of human embryonic neural stem cells (NSCs).</p><p><b>METHODS</b>The samples were divided into three groups. In Group One, NSCs were cultured in DMED/F12 in which Schwann cells had grown for one day. In Group Two, NSCs and Schwann cells were co-cultured. In Group Three, NSCs were cultured in DMEM/F12. The morphology of NSCs was checked and beta-tubulin, GalC, hoechst 33342 and GFAP labellings were detected.</p><p><b>RESULTS</b>In Group One, all neural spheres were attached to the bottom and differentiated. The majority of them were beta-tubulin positive while a few of cells were GFAP or GalC positive. In Group Two, neural spheres remained undifferentiated and their proliferation was inhibited in places where Schwann cells were robust. In places where there were few Schwann cells, NSCs performed in a similar manner as in Group One. In Group Three, the cell growth state deteriorated day after day. On the 7th day, most NSCs died.</p><p><b>CONCLUSION</b>The secretion of rat Schwann cells has a growth supportive and differentiation-inducing effect on human NSCs.</p>

Schwann cells transplantation promoted and the repair of brain stem injury in rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To explore the possibility of Schwann cells transplantation to promote the repair of injured brain stem reticular structure in rats.</p><p><b>METHODS</b>Schwann cells originated from sciatic nerves of 1 to 2-day-old rats were expanded and labelled by BrdU in vitro, transplanted into rat brain stem reticular structure that was pre-injured by electric needle stimulus. Immunohistochemistry and myelin-staining were used to investigate the expression of BrdU, GAP-43 and new myelination respectively.</p><p><b>RESULTS</b>BrdU positive cells could be identified for up to 8 months and their number increased by about 23%, which mainly migrated toward injured ipsilateral cortex. The GAP-43 expression reached its peak in 1 month after transplantation and was significantly higher than that in the control group. New myelination could be seen in destructed brain stem areas.</p><p><b>CONCLUSION</b>The transplantation of Schwann cells can promote the restoration of injured brain stem reticular structure.</p>