Aldosterone antagonist inhibits fibrosis-induced NOX4 protein expression in hepatic cells and tissues of rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the inhibitory potential of aldosterone antagonist on NOX4 protein expression in hepatic fibrosis by using a rat model of carbon tetrachloride (CCl4)-induced hepatotoxicity.</p><p><b>METHODS</b>Twenty-four male Wistar rats were randomly divided into three equal groups: fibrosis model group (receiving three subcutaneous injections per week of 2.5 ml/kg 40% CCl4); spironolactone (Sp)-treated fibrosis model group (receiving CCl4 regimen plus three injections per day of 20 mg/kg Sp in olive oil); negative-treatment fibrosis model group (receiving CCl4 regimen plus three injections per day of olive oil alone). Unmanipulated rats (receiving no CCl4 and no supplemental treatments) served as normal controls. After 4 weeks, liver histology was carried out to assess cytotoxicity (by hematoxylin-eosin staining), fibrosis (by Masson staining and METAVIR scoring), and NOX4 protein expression (by immunohistochemistry). In addition, in vitro analyses of immortalized rat hepatic stellate cells, HSC-T6, were performed to evaluate dose-response (10-9, 10-7 and 10-5 mol/L) and time-response (6, 12 and 24 h) of aldosterone agonist (Ald) and an aldosterone antagonist, eplerenone (EPLE). Effects on NOX4 protein expression were evaluated by western blotting.</p><p><b>RESULTS</b>The fibrosis model group showed significantly more fibrosis than the normal control group (16.060 +/- 0.300 vs. 2.471 +/- 0.160, P = 0.000]; however, the Sp-treated fibrosis model group showed significantly less CCl4-induced fibrosis (5.761 +/- 0.152 vs. model: 16.060 +/- 0.300, P = 0.000). The fibrosis model group also showed significantly higher NOX4 protein expression in liver tissues than the normal control group (7.231 +/- 0.211 vs. 1.350 +/- 0.252, P = 0.000), and the Sp-treated fibrosis model tissues showed significantly less CCl4-induced up-regulated NOX4 protein expression (4.270 +/- 0.242 vs. model: 7.231 +/- 0.211, P = 0.000]. Ald induced up-regulated NOX4 protein expression in HSC-T6 cells in dose- and concentration-dependent manners, with the peak expression being induced by the 10-5 mol/L concentration and 24 h exposure. The Ald-treated cells expressed significantly more NOX4 protein than the untreated control cells (0.710 +/- 0.011 vs. 0.316 +/- 0.015, P = 0.000]. and the EPLE-treated cells showed significantly less Ald-induced up-regulated NOX4 expression (0.615 +/- 0.014 vs. 0.710 +/- 0.011, P = 0.000].</p><p><b>CONCLUSION</b>Aldosterone antagonists inhibit the fibrosis-induced NOX4 protein expression in rat hepatic cells.</p>

Inhibitory effect of angiotensin (1-7) on hepatic sinusoid angiogenesis in bile duct ligation-induced hepatic fibrosis of rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the inhibitory effect of angiotensin (1-7) on hepatic sinusoid angiogenesis using a rat model of hepatic fibrosis.</p><p><b>METHODS</b>Eighteen male Wistar rats were randomly divided into three equal groups for sham operation (untreated/uninduced control group), bile duct ligation (BDL) (untreated model group), or BDL with angiotensin (1-7) treatment (treated model group). Histological analysis was used to assess the liver fibrosis score, by hematoxylin-eosin staining, and the level of fibrosis, by Masson's trichrome staining. Immunohistochemistry, western blotting, and immunofluorescence were used to assess the expression of the angiogenesis markers vWF, VEGFA, and CD31.</p><p><b>RESULTS</b>Compared with the untreated/uninduced control group, the untreated BDL model group showed remarkably higher fibrosis score, area of the type I collagen expression, and expression levels of vWF, VEGFA, and CD31. However, the angiotensin (1-7)-treatment protected against the BLD-related changes, as evidenced by decreased robustness and down-regulation of the corresponding indicators. Moreover, the expression level of VEGFA was highly correlated to the expression level of vWF (r = 0.956, P = 0.000).</p><p><b>CONCLUSION</b>BDL-induced hepatic fibrosis is accompanied by significant increases in angiogenesis-related factors, but angiotensin (1-7) treatment may inhibit hepatic sinusoid angiogenesis during the liver fibrosis process.</p>

Angiotensin (1-7) inhibits angiotensin II-stimulated expression of connective tissue growth factor mRNA in hepatic stellate cells / 中华肝脏病杂志

To explore the angiotensin peptide [Ang (1-7)]-mediated inhibition of Ang II in human hepatic stellate cells (HSCs) and determine the involvement of the ACE2-Ang (1-7)-Mas axis. The human HSC line, LX2, was used in all experiments, and divided into control (unstimulated) and Ang II-stimulated (10-6 mol/L) groups. The Ang II-stimulated cells were further divided among several pre-treatment (prior to Ang II) groups: ROCK-inhibited (Y27632 blocking agent, 10-6 mol/L); irbesartan-inhibited (AT-1 receptor antagonist, 10-6 mol/L); and Mas receptor-inhibited (A779 Mas receptor antagonist, 10-6 mol/L). To explore the potential inhibitory effects of various Ang family members, the Ang II-stimulated and pre-treated LX2 cells were exposed to Ang (1-7) (10-6 mol/L) for 24 h. Western blot, reverse transcription-polymerase chain reaction (RT-PCR), and QuantiGene assay were used to assess changes in protein and mRNA expression levels of RhoA, ROCK, and connective tissue growth factor (CTGF). Compared with the control group, Ang II-stimulated cells showed significantly increased levels of RhoA protein (0.337+/-0.074 vs. 0.870+/-0.093), ROCK2 mRNA (0.747+/-0.061 vs. 0.368+/-0.023), and CTGF mRNA (0.262+/-0.007 vs. 0.578+/-0.028) (all, P less than 0.01). Pre-treatment with irbesartan or Y27632 eliminated these responses. Ang (1-7) inhibited the Ang II-stimulated up-regulation of RhoA, ROCK, and CTGF. Ang (1-7) can inhibit the Ang II-stimulated up-regulation of RhoA, ROCK and CTGF in hepatic stellate cells, indicating that the ACE2-Ang (1-7)-Mas axis, an important branch of the renin-Ang-aldosterone system is involved in the occurrence and development of liver fibrosis.