ABSTRACT
Objective@#To investigate the distribution and drug resistance situation of staphylococcus aureus (SA) and methicillin-resistant staphylococcus aureus (MRSA) from the classroom environments in primary schools of Guangzhou.@*Methods@#The air and the surfaces of door handles, desks, chairs, light switches and floor were sampled in the classrooms of 8 primary schools selected through stratified clustering method in Guangzhou from May to June, 2016. SA and MRSA were isolated and identified, and drug sensitivity tests were conducted.@*Results@#A total of 760 samples were collected, the detection rate of SA and MRSA were 8.8% and 4.2%, respectively. There were statistically significant differences in the detection rate of staphylococcus aureus among different sampling sites(P<0.01).Detection of SA and MRSA on the floor,light’s witches and surface of deskes was both above 6.0%. The multiple drug resistance rate of MRSA was up to 100.0%, and the main resistance mode was Penicillin-Erythromycin-Rifampin-Tetracycline-Teicolanin.@*Conclusion@#MRSA can be detected in air, door handles, desk surface, chair surface, light switch and floor of primary schools. Relevant administration departments should pay attention to the environments health of Guangzhou primary schools.
ABSTRACT
@#【Objective】To investigate the function of LRP6 and canonical Wnt/β-catenin signaling pathway in Doxorubicin-induced cardiomyopathy.【Methods】To establish the model of Dox cardiomyopathy in vitro and in vivo，H9C2 cells were treated with Dox（1 μmol/L）for 12 h and twelve SD rats were divided into two groups equally，and intraperitoneally injected with normal saline and Dox respectively. The changes of protein and mRNA levels were detected by western blot and qPCR. Cardiomyocytes were transfected with siRNA to knockdown LRP6. Mitochondrial membrane potential，nuclear condensation and matrix swelling were determined by Rhodamine 123 ，Hoechst and Mitotracker staining respectively. The apoptosis rate of cells was measured by flow cytometric analysis. 【Results】 The model of Dox cardiomyopathy was successfully established in vitro and in vivo. Dox downregulated the mRNA and protein levels of LRP6. Knockdown of LRP6 aggravated the cell apoptosis and mitochondrial damage induced by Dox. Both Dox and silencing LRP6 induced the downregulation of β - catenin ，and activation of β - catenin reversed the cardiomyocytes apoptosis caused by Dox. 【Conclusions】 Dox downregulated the expression of LRP6 and inhibited canonical Wnt/β- catenin signaling pathway，thus causing cardiomyocytes apoptosis and mitochondrial dysfunction.
ABSTRACT
The aim of this study was to investigate the effect of Wnt5a on the vincristine (VCR) resistance in human ovarian carcinoma SKOV3 cells and its possible mechanism. The drug-resistant SKOV3/VCR cells were established by stepwise exposure to VCR, and then the SKOV3/VCR cells were stably transfected with specific shRNA interference plasmid vector targeting for Wnt5a. The mRNA expression level of Wnt5a was measured by RT-PCR. CCK-8 assay was used to detect the cell viability of SKOV3/VCR cells. The apoptosis was analyzed by flow cytometry. The protein expression levels of Wnt5a, MDR1, Survivin, β-catenin, Akt, p-Akt(S473), GSK3β and p-GSK3β(Ser9) were detected by Western blot. The result showed that SKOV3/VCR cells had significantly higher protein expression levels of Wnt5a, MDR1, Survivin and β-catenin, phosphorylation levels of Akt and GSK3β, and mRNA expression level of Wnt5a, compared with SKOV3 cells (P < 0.05). WNT5A gene silencing significantly increased the sensitivity of SKOV3/VCR cells to VCR, the IC of VCR being decreased from 38.412 to 9.283 mg/L (P < 0.05), synergistically enhanced VCR-induced apoptosis of SKOV3/VCR cells (P < 0.05), down-regulated the protein expression levels of MDR1, β-catenin and Survivin (P < 0.05), and inhibited phosphorylation of Akt and GSK3β (P < 0.05). Meanwhile, LY294002 (PI3K inhibitor) decreased the protein expression levels of MDR1, β-catenin and Survivin, as well as the phosphorylation levels of Akt and GSK3β in SKOV3/VCR cells (P < 0.05). These results suggest that WNT5A gene silencing reverses VCR resistance in SKOV3/VCR cells possibly through blocking the PI3K/Akt/GSK3β/β-catenin signaling pathway, and thus down-regulating the protein expression levels of MDR1 and Survivin.