Effects of ursolic acid on activation of NOX2/ROS/NLRP3 inflammasome in liver fibrosis rats / 基础医学与临床

Objective To investigate the effect of ursolic acid(UA) on NOX2/ROS/NLRP3 inflammasome activation in carbon tetrachloride(CCl4)-induced liver fibrosis SD rat,and to observe the improvement of collagen deposition in liver tissues. Methods All rats were randomly divided into 3 group:control group,CCl4model group,UA treatment group. Liver fibrosis model SD rats was established by the CCl4-induced method and half of them was used as UA treatment group. Serum ALT was detected by ALT detection kit.The liver pathology and collagen deposition were ob-served by HE and Sirius-red staining. The mRNA expression of Nox2,Nlrp3,Caspase1,IL-1β in liver tissues was detected by RT-qPCR. The protein expression of NOX2,NLRP3,caspase-1 and IL-1β in liver tissues was detected by Western blot and immunohistochemistry and the ROS generation in liver tissues was detected by DCFH-DA fluores-cence probe. Results Compared with control group,in the CCl4model group,the serum ALT was much higher (P<0.05);the Ishak's fibrosis score and collagen deposition was significantly increased(P<0.05) and mRNA of Nox2, Nlrp3,Caspase1,IL-1β was increased.In addition,both the NOX2,NLRP3,caspase-1 p10 and IL-1β protein expres-sion and ROS level (P<0.05) of CCl4model group were significant increased.Compared with CCl4model group,in the UA treatment group Ishak's fibrosis score,collagen deposition and ALT decreased.Both mRNA expression of the Nox2, Nlrp3,Caspase1,IL-1β and protein expression of NOX2,NLRP3,caspase-1 p10 and IL-1β as well as ROS were signif-icant decreased,but the caspase-1 p45 protein level has no difference among all these groups (P>0.05). Conclusions Ursolic acid attenuates the liver injury and reduces the collagen deposition,which may relate to its inhibitory effects on NOX2/ROS/NLRP3 inflammasome activation to reduce IL-1β releasing.

Prevalence of Helicobacter pylori cagA, vacA, and iceA genotypes in children with gastroduodenal diseases / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of cagA, vacA, and iceA genotypes in the isolated strains of Helicobacter pylori (H.pylori) from children with gastroduodenal diseases in Jiangxi, China, as well as the association between cagA, vacA, and iceA genotypes and the type of gastroduodenal diseases.</p><p><b>METHODS</b>The samples of gastric antral mucosa were collected from 316 children with gastroduodenal diseases in Jiangxi, and a total of 107 strains of H.pylori were isolated. The genomic DNA of these strains was extracted, and PCR was used to determine the ureA, cagA, vacA, and iceA genotypes.</p><p><b>RESULTS</b>Of all the 107 isolated strains of H.pylori, the detection rates of ureA and cagA genes were 100% (107/107) and 94.4% (101/107) respectively. The overall detection rate of vacA gene was 100% (107/107), and the detection rates of vacAs1a, vacAs1c, vacAm1, and vacAm2 genes were 74.8% (80/107), 25.2% (27/107), 29.9% (32/107), and 69.2% (74/107) respectively, with both vacAm1 and vacAm2 genes detected in 0.9% (1/107) of all H.pylori strains. In the chimera of vacA gene, the detection rates of vacAs1a/m1, vacAs1a/m2, vacAs1c/m1, and vacAs1c/m2 genes were 26.2% (28/107), 51.4% (55/107), 3.7% (4/107), and 17.8% (19/107) respectively (P<0.001). The detection rates of iceA1 and iceA2 genes were 79.4% (85/107) and 9.3% (10/107), respectively (P<0.001), and both iceA1 and iceA2 genes were detected in 7.5% (8/107) of all strains. The detection rates of the genotypes of H.pylori showed no significant differences between the peptic ulcer, chronic gastritis, and duodenal bulbar inflammation groups (P>0.05).</p><p><b>CONCLUSIONS</b>The dominant genotypes of H.pylori are cagA, vacAs1a/m2, and iceA1, and there are mixed infections with H.pylori strains of different genotypes in children with gastroduodenal disease from Jiangxi, China. The genotypes of H.pylori are not associated with the type of gastroduodenal disease.</p>

The role and mechanism of NADPH oxidase in leptin-induced reactive oxygen species production in hepatic stellate cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate whether or not NADPH oxidase (NOX) participates in leptin-induced reactive oxygen species (ROS) production in hepatic stellate cells (HSC) and to explore the possible mechanism.</p><p><b>METHODS</b>HSC-T6 cells (rat hepatic stellate cells line) were divided into nine groups: Group1: leptin (100 ng/ml) treated; Group2-6: leptin treated together with inhibitors that block different ROS-producing systems: diphenylene-iodonium (DPI) (20 micromol/L), Rotenone (20 micromol/L), Metyrapone (250 micromol/L), Allopurinol (100 micromol/L) and Indomethacin(100 micromol/L); Group7: leptin treated together with Janus kinase (JAK) inhibitor AG490 50 micromol/L; Group8: normal control group (treated DMEM with 0.1% DMSO); Group9: negative control group (untreated). Intracellular ROS levels were measured with dichlorodihydrofluorescein diacetate (DCFH-DA) dye assay by Fluorescence microscope and/or flow cytometry. NOX activity was analyzed by using spectrophotometer to calculate the absorbance of NADPH. The mRNA levels of Rac1 and p22Phox were evaluated by RT-PCR.</p><p><b>RESULTS</b>(1) Leptin increased significantly the ROS production as compared to normal control group (92.91+/-4.19 vs.27.56+/-6.27, P<0.01) in HSC-T6 cells. Both the NADPH oxidase inhibitor DPI and AG490 (50 micromol/L) blocked the ROS production, inhibitors of other ROS producing systems had no significant effect on ROS production induced by lepin (P is more than 0.05). (2) Leptin treated HSC-T6 cells for 1 hour up-regulated the NOX activity significantly compared with that in normal control group [(1.90+/-0.22) pmol.min(-1).mg(-1) vs. (0.76+/-0.06) pmol.min(-1).mg(-1), P<0.05]. Furthermore, the NOX activity increased after being treated with leptin for 12 hours and 24 hours than being treated for 1 hour. Leptin-induced up-regulation of NOX activity was inhibited by pretreatment with DPI or AG490. (3) The RT-PCR results indicated that mRNA expressions of Rac1 and p22Phox in HSC-T6 cells with 12 hours of leptin stimulation increased significantly as compared with normal control group (0.41+/-0.13 vs 0.14+/-0.08, 0.45+/-0.12 vs 0.20+/-0.08, all P<0.05), while the DPI and AG490 had no effect on the mRNA expressions of Rac1 and p22Phox.</p><p><b>CONCLUSION</b>NOX is the main cellular source of the reactive oxygen species (ROS) generated by HSCs in response to leptin stimulation. The mechanism is probably that leptin can directly activate NOX through JAK signal transduction and hence induce the expression of NOX subunit to promote the activity of NOX which generates considerable ROS in HSC.</p>

Effect of ursolic acid on proliferation and apoptosis of hepatic stellate cells in vitro / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the effect of ursolic acid on proliferation and apoptosis of hepatic stellate cells (HSC) in vitro and explore the mechanisms of apoptosis of HSC induced by ursolic acid by studying the expressions of apoptosis-regulating proteins Bcl-2, Bax and Caspase 3 in HSC.</p><p><b>METHODS</b>Hepatic stellate cells HSC-T6 and hepatocytes L02 were incubated with different concentrations of ursolic acid (25, 50, 75, 100, 125 and 150 micromol/L) for 24 h, 48 h and 72 h. The effect of ursolic acid on the cell proliferation was studied by methyl thiazolyl tetrazolium (MTT) colorimetric assay. The rate of HSC-T6 apoptosis was identified by flow cytometry (FCM) and the morphological change of apoptosis was observed with light microscopy. The expressions of apoptosis-regulating protein Bcl-2, Bax and Caspase 3 in HSC-T6 after apoptosis induced by ursolic acid were examined by immunocytochemical staining assay.</p><p><b>RESULTS</b>MTT analysis indicated administration of 25-150 micromol/L ursolic acid incubated with HSC-T6 for 24 h, 48 h and 72 h significantly inhibited HSC-T6 proliferation in a dose-dependent and time-dependent manner compared with the control group. Promotive effect of ursolic acid on proliferation of hepatocyte L02 was observed in the 25, 50, 75 micromol/L concentration groups. Ursolic acid inhibited L02 proliferation when its concentration was higher than 100 micromol/L and for 72 hours or longer. HE stained histological slides demonstrated morphologic changes of HSC-T6, including karyorrhexis and cytoplasm vacuolization, when they were treated with ursolic acid at 75 micromol/L concentrations for 48 h. FCM showed the apoptosis ratios of HSC-T6 were 10.30%+/-3.85%, 21.87%+/-4.46% and 31.33%+/-6.18% after treating HSC-T6 with ursolic acid at concentrations of 25, 50 and 75 micromol/L for 48 h. They were significantly higher than that of the control group 2.93%+/-1.60%. Immunocytochemistry also indicated the expressions of Bax and caspase 3 protein in HSC-T6 cells were up-regulated in a dose-dependent manner, but expressions of Bcl-2 protein were not significantly different from that of the blank control group (P more than 0.05).</p><p><b>CONCLUSIONS</b>Ursolic acid could significantly inhibit HSC proliferation and induce apoptosis in a dose-dependent and time-dependent manner. Ursolic acid in low concentration promotes proliferation of L02 cells, but in high concentrations (more than 100 micromol/L) it inhibits the growth of hepatocytes. Expressions of Bax and Caspase 3 in apoptotic HSC were increased; expressions of Bcl-2 protein were not significantly different from that of the control group, while Bcl-2/Bax ratio was reduced. Our results suggest that HSC-T6 cell apoptosis induced by ursolic acid occurs through mechanisms involving mitochondrial pathways and Bcl-2 family proteins.</p>