Heme oxygenase-1 prevents non-alcoholic steatohepatitis through suppressing hepatocyte apoptosis in mice

<p>Abstract</p> <p>Objective</p> <p>Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, has been reported to have potential antioxidant properties. However, the role of HO-1 on hepatocyte apoptosis remains unclear. We aim to elucidate the effects of HO-1 on oxidative stress related hepatocellular apoptosis in nutritional steatohepatitis in mice.</p> <p>Methods</p> <p>C57BL/6J mice were fed with methionine-choline deficient (MCD) diet for four weeks to induce hepatic steatohepatitis. HO-1 chemical inducer (hemin), HO-1 chemical inhibitor zinc protoporphyrin IX (ZnPP-IX) and/or adenovirus carrying HO-1 gene (Ad-HO-1) were administered to mice, respectively. Hepatocyte apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, the mRNA and protein expression of apoptosis related genes were assayed by quantitative real-time PCR and Western blot.</p> <p>Results</p> <p>Hepatocyte signs of oxidative related apoptotic injury were presented in mice fed with MCD diet for 4 weeks. Induction of HO-1 by hemin or Ad-HO-1 significantly attenuated the severity of liver histology, which was associated with decreased hepatic lipid peroxidation content, reduced number of apoptotic cells by TUNEL staining, down-regulated expression of pro-apoptosis related genes including Fas/FasL, Bax, caspase-3 and caspase-9, reduced expression of cytochrome p4502E1 (CYP2E1), inhibited cytochrome c (Cyt-c) release, and up-regulated expression of anti-apoptosis gene Bcl-2. Whereas, inhibition of HO-1 by ZnPP-IX caused oxidative stress related hepatic injury, which concomitant with increased number of TUNEL positive cells and up-regulated expression of pro-apoptosis related genes.</p> <p>Conclusions</p> <p>The present study provided evidences for the protective role of HO-1 in preventing nutritional steatohepatitis through suppressing hepatocyte apoptosis in mice.</p

Combination of Raman tweezers and quantitative differential interference contrast microscopy for measurement of dynamics and heterogeneity during the germination of individual bacterial spores

Raman tweezers and quantitative differential interference contrast (DIC) microscopy are combined to monitor the dynamic germination of individual bacterial spores of Bacillus species, as well as the heterogeneity in this process. The DIC bias phase is set properly such that the brightness of DIC images of individual spores is proportional to the dipicolinic acid (DPA) level of the spores, and an algorithm is developed to retrieve the phase image of an individual spore from its DIC image. We find that during germination, the rapid drop in both the intensity of the original DIC image and the intensity of the reconstructed phase image precisely corresponds to the release of all DPA from that spore. The summed pixel intensity of the DIC image of individual spores adhered on a microscope coverslip is not sensitive to the drift of the slide in both horizontal and vertical directions, which facilitates observation of the germination of thousands of individual spores for long periods of time. A motorized stage and synchronized image acquisition system is further developed to effectively expand the field of view of the DIC imaging. This quantitative DIC technique is used to track the germination of hundreds or thousands of individual spores simultaneously

Analyzing quantum jumps of one and two atoms strongly coupled to an optical cavity

We induce quantum jumps between the hyperfine ground states of one and two Cesium atoms, strongly coupled to the mode of a high-finesse optical resonator, and analyze the resulting random telegraph signals. We identify experimental parameters to deduce the atomic spin state nondestructively from the stream of photons transmitted through the cavity, achieving a compromise between a good signal-to-noise ratio and minimal measurement-induced perturbations. In order to extract optimum information about the spin dynamics from the photon count signal, a Bayesian update formalism is employed, which yields time-dependent probabilities for the atoms to be in either hyperfine state. We discuss the effect of super-Poissonian photon number distributions caused by atomic motion.Comment: 12 pages, 13 figure