ABSTRACT
Objective To investigate the effect of transforming growth factorβreceptor typeⅠ(TGFBRⅠ) on adipocyte differentiation by using a small interference RNA (siRNA). Methods The siRNA targeting TGFBRⅠwas synthesized as experimental group, and negative control siRNA was used as control group. The efficiency of TGFBRⅠdepletion and the expression levels of adipocyte-specific transcription factors CCAAT enhancer binding protein α (C/EBPα),peroxisome proliferator-activated receptor gamma (PPARγ) and adipocyte marker gene fatty acid binding protein 4 (FABP4) were detected by quantitative real-time PCR. After treating with adipocyte differentiation agents for 5 days, the cells were stained with oil red O, and the staining of adipocyte was observed and photographed by laser confocal microscope. In addition, with isopropanol extracted oil red O, optical density values of oil red O were measured at a wavelength of 520, and which were compared between groups. Results After transfection of TGFBRⅠ siRNA, gene expression levels of TGFBRⅠwere significantly reduced in ST2 cells, the number of differentiated adipocytes was significantly increased, and the mRNA levels of adipocyte specific transcription factor C/EBPαand PPARγand adipocyte marker gene FABP4 were enhanced compared with those of control group. After treating with adipocyte differentiation agents for 5 days,the number of lipid droplets of cells with transfection of TGFBRⅠsiRNA was increased than that of cells with transfection of control siRNA. The value of optical density was higher in cells with transfection of TGFBRⅠsiRNA than that of control siRNA group. Conclusion TGFBRⅠsiRNA can effectively facilitate adipocyte formation, which suggests that TGFBRⅠis an important regulator of adipogenic differentiation from progenitor cells.
ABSTRACT
Trans-cranial magnetic stimulation (TMS) is the process that excitable human brain tissue is activated with the electric field induced from a changing magnetic field. Magnetic focusing characteristic is one of the most important technical considerations of coil design in TMS. In this paper, a half solenoid coil was proposed to be used in TMS and the magnitude profile of the induced electric fields in different depth was studied based on the induced electric field theory of magnetic stimulating coil. The magnitude profile of the induced electric fields produced by half solenoid coils was compared with that of butterfly-shaped coils. The result shows that half solenoid coils retain the good focusing characteristics of the main lobe of the butterfly-shaped coils. At the same time side effect of the side lobes on notargeted tissue is mitigated, which would otherwise lead to undesirable stimulation. Hence magnetic focusing is optimized, which is expected to give a more accurate delivery of the focal point for more effective stimulation.