Pioglitazone ameliorates nonalcoholic steatohepatitis by down-regulating hepatic nuclear factor-kappa B and cyclooxygenases-2 expression in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pioglitazone is effective in nonalcoholic steatohepatitis (NASH), but the mechanisms of action are not completely understood. This study was designed to investigate the effects of pioglitazone on hepatic nuclear factor-kappa B (NF-κB) and cyclooxygenases-2 (COX-2) expression in NASH rats.</p><p><b>METHODS</b>Thirty Sprague-Dawley male rats were randomly assigned to a control group (n = 10), NASH group (n = 10), and pioglitazone treatment group (n = 10). Liver tissues were processed for histology by hematoxylin & eosin and Masson stained. Serum alanine aminotransferase (ALT), cholesterol, triglyceride, fasting blood glucose (FBG), fasting insulin (FINS) levels and biochemical parameters of antioxidant enzyme activities, tumor necrosis factor alpha (TNF-α), prostaglandin E(2) (PGE(2)) levels in serum and liver were measured. The mRNA and protein expression of peroxisome proliferator-activated receptor gamma (PPARγ), NF-κB and COX-2 were determined by real-time polymerase chain reaction, Western blotting and immunohistochemistry. One-way analysis of variance (ANOVA) and Wilcoxon's signed-rank test was used for the statistical analysis.</p><p><b>RESULTS</b>There were severe steatosis, moderate inflammatory cellular infiltration and fibrosis in NASH rats. After pioglitazone treatment, steatosis, inflammation and fibrosis were significantly improved compared with the NASH group (χ(2) = 20.40, P < 0.001; χ(2) = 20.17, P < 0.001; χ(2) = 13.98, P = 0.002). Serum ALT, cholesterol, triglyceride, FBG, FINS levels were significantly elevated in the NASH group (P < 0.05). In the NASH group, total anti-oxidation competence (T-AOC), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) levels in serum and liver were conspicuous disordered than those parameters in the control group. Meanwhile, TNF-α and PGE(2) levels in serum and liver were significantly increased compared with the control group. Immunohistochemistry showed NF-κB and COX-2 expression in liver was significantly elevated. However, PPAR? level was decreased in the NASH group. Real-time PCR and Western blotting revealed mRNA and protein expression of COX-2 were increased in the NASH group compared with the control group (0.57 ± 0.08 vs. 2.83 ± 0.24; 0.38 ± 0.03 vs. 1.00 ± 0.03, P < 0.001 and P = 0.004, respectively). After pioglitazone intervention, all of those parameters markedly improved (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>Down-regulating hepatic NF-κB and COX-2 expression, at least in part, is one of the possible therapeutic mechanisms of pioglitazone in NASH rats.</p>

Role of integrin α4β7 in the pathogenesis of ulcerative colitis in rats / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the role of integrin α4β7 in the development of ulcerative colitis (UC) in rats.</p><p><b>METHODS</b>Sixty Sprague-Dawley rats were randomly divided into the control group (acetone enema), the model group (2,4-dinitrochlorobenzene, DNCB enema), and the α4 intervention group. Colonic mucosa of different groups was observed and compared in terms of pathology and cytokine changes(IL-2 and IL-6) using ELISA. Semi-quantitative RT-PCR was used to detect the colon α4β7 expression. Integrin α4β7(+) lymphocytes in the portal vein of rats were determined by flow cytometry.</p><p><b>RESULTS</b>The expression of α4 mRNA was 0.68±0.24 in the model group and 0.58±0.37 in the intervention group, and the expression of β7 mRNA was 0.84±0.37 in the model group and 0.65±0.30 in the intervention group, which were all significantly higher as compared to those in the control group(0.15±0.13 for α4 and 0.24±0.62 for β7, P<0.01). The proportions of integrin α4β7 positive lymphocytes in the portal vein in the model group and intervention group were significantly higher than that in the control group [(76.7±8.2)% and (68.2±7.6)% vs. (14.7±6.7)%, P<0.01]. The expression of IL-2 and IL-6 and the result of macroscopic and microscopic scores in the intervention group were lower than those in the model group(P<0.05).</p><p><b>CONCLUSIONS</b>High expression of α4β7 may play an important role in experimental colon mucosa inflammation in rats with ulcerative colitis. The blockade of integrin α4β7 may be a potential target to reduce colonic mucosa inflammation.</p>

Role of secondary lymphoid tissue chemokine in the pathogenesis of rat ulcerative colitis / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the effect of secondary lymphoid tissue chemokine (SLC) on experimental colon lesions in rats with ulcerative colitis.</p><p><b>METHODS</b>Sixty Sprague-Dawley rats were randomly divided into control group, model group and SLC intervention group. Colonic mucosal lesions of different groups were observed with HE staining for inflammation and lymphocyte homing situation. Cytokine IL-2 and IL-6 levels were measured by ABC-ELISA. Semi-quantitative RT-PCR was used to examine the colonic SLC expression.</p><p><b>RESULTS</b>Intestinal inflammation score and colonic cytokine levels were significantly different among three groups (P<0.05, P<0.01). Abnormal lymphocyte homing phenomenon under colonic mucosa was found in the model group and the intervention group. SLC mRNA expression of the model and intervention groups increased significantly compared with the control group (0.846+/-0.047, 0.768+/-0.135 vs 0.312+/-0.112, P<0.01). However, there was no significant difference between model group and intervention group.</p><p><b>CONCLUSIONS</b>SLC may play an important role in experimental colonic mucosal inflammation in rats with ulcerative colitis. Blockade of SLC may be one of effective ways in reducing colonic mucosal inflammation.</p>

Expression of vascular endothelial growth factors (VEGF)-A, -C and -D and their prognostic significance and relationship with angio- and lymphangiogenesis in gastric cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expressions of vascular endothelial growth factors (VEGF)-A, -C and -D and their prognostic significance and relation to angio- and lymphangiogenesis in gastric cancer.</p><p><b>METHODS</b>The expression of VEGF-A, -C and -D in 123 primary gastric cancers was detected by immunohistochemical staining. The lymphatic vessel density (LVD) and microvessel density (MVD) were assessed after immunohistochemical double-staining with D2-40 and CD34, respectively. The correlation between the expression of those VEGF factors and clinicopathological parameters were analyzed by univariate method. The overall survival was evaluated by Kaplan-Meier method and log-rank test. Multivariate analysis was carried out using Cox proportion hazard model.</p><p><b>RESULTS</b>The positive expression rate of VEGF-A, -C and -D in primary gastric cancer samples were 64.2%, 65.9% and 41.5%, respectively. High expression of VEGF-A, or -C or -D, or any two of them was correlated with high LVD (P < 0.05). High expression of both VEGF-A and -C was associated with high MVD, lymph node metastasis, LVI and MVI (P < 0.05). Both VEGF-C and -D high expression was correlated with LVI and lymph node metastasis (P < 0.05). The patients with high expression of these factors had a statistically shorter overall survival (P < 0.05). The patients with both VEGF-A and -C expression had the shortest survival (56 months). Multivariate analysis showed that VEGF-A high expression, MVD, lymph node metastasis and depth of tumor invasion were independent survival predictors (P = 0.033, 0.002, 0.019 and P < 0.001, respectively).</p><p><b>CONCLUSION</b>High expression of both VEGF-A and -C imply high potential of lymphangiogenesis, metastasis and poorer survival in gastric cancer patients. High expression of VEGF-C and -D may induce lymphangiogenesis and promote lymph node metastasis, but only VEGF-A is an independent predictor of survival.</p>

Antitumor effects of specific cyclooxygenase inhibitors combined with chemotherapeutic agents on gastric cancer cells in vitro / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effects of two specific cyclooxygenase inhibitors (SCI), rofecoxib and celecoxib, combined with chemotherapeutic drugs 5-Fu, DDP and VP-16 on gastric cancer cell line BGC-823, and to evaluate whether specific cyclooxygenase inhibitors can be used as a synergetic agent in chemotherapy.</p><p><b>METHODS</b>The gastric cancer cell line BGC-823 cells were incubated for 48 hours with rofecoxib and celecoxib, 5-Fu, DDP and VP-16 (concentration gradient of 5-Fu, DDP and VP-16:1 microg/ml, 10 microg/ml and 100 microg/ml), or in combination, respectively. MTT working solution was added to each culture and calculated the survival rates of gastric cancer cells. Median-effect principle and Professor Jin's evaluation methods were applied to detect the interaction between the specific cyclooxygenase inhibitors and chemotherapeutic agents.</p><p><b>RESULTS</b>The inhibition rates of gastric cancer cells were 42.63% +/- 1.26% and 50.67% +/- 2.35% by treatment with 0.1 micromol/L rofecoxib and 50 micromol/L celecoxib, respectively. The inhibition rates of gastric cancer cells by treatment with 5-Fu, DDP and VP-16 at different concentrations (1 microg/ml, 10 microg/ml and 100 microg/ml) were 39.75% +/- 3.14%, 49.96% +/- 2.08%, 87.93% +/- 3.66%; 48.28% +/- 2.08%, 59.46% +/- 1.69%, 88.23% +/- 4.81%; and 29.23% +/- 3.27%, 49.34% +/- 3.75%, 79.24% +/- 2.44%, respectively. However, the inhibition rates showed a synergetic role while combined the two SCI (0.1 micromol/L rofecoxib and 50 micromol/L celecoxib) with chemotherapeutic agent at different concentrations (P <0.05).</p><p><b>CONCLUSION</b>Both rofecoxib and celecoxib have an ability to suppress gastric cancer cells in vitro, and the synergetic role becomes evident when rofecoxib and celecoxib are combined with chemotherapeutic agents at different concentrations, which indicate that the two specific cyclooxygenase inhibitors may be used as a chemotherapeutic sensitizer.</p>

The role of peroxisome proliferators-activated receptor gamma (PPARgamma) during activation of hepatic stellate cells / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To observe the role of PPARgamma during the activation process of hepatic stellate cells (HSC).</p><p><b>METHODS</b>By morphology and RT-PCR, we study the changes of expression of PPARgamma in culture-activated HSC or in vivo activated HSC induced by dimethylnitrosamine (DMN).</p><p><b>RESULTS</b>In vitro, the expression level of PPARgamma in freshly isolated HSC (0.72+/-0.01) significantly reduced to 0.48+/-0.03 on the third day of culture (t = 19.8372, P<0.01), and reduced 70% on the seventh culture-day and could not be detected after the second passage. In vivo, HSC freshly isolated from normal control rats expressed PPARgamma (0.76+/-0.01). During the development of rat liver fibrosis induced by DMN, the expression level significantly reduced to 0.46+/-0.02 after the third injection of DMN (t = 29.5318, P<0.01), and reduced 66% on the end of first week and could not be detected on the end of second and third week.</p><p><b>CONCLUSION</b>The expression of PPARgamma might play an important role on the maintenance of resting-form of HSC, and the reduction of expression of PPARgamma might be an early event during the activation process of HSC.</p>

Therapeutic effects of octreotide on hepatofibrosis-induced with carbon tetrachloride in rats / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To investigate the therapeutic effects and mechanism of octreotide on experimental hepatic fibrosis in rats.</p><p><b>METHODS</b>Hepatofibrotic rats models were established with carbon tetrachloride. All the experimental rats were divided into four groups: normal control group, pre-and post-treatment model group, and octreotide-treated group in which the rats were injected subcutaneously with octreotide at the dose of 50ng/100g, twice daily, for thirty days. Serum levels of hyaluronic acid (HA), laminin (LN) and pro-collagen type III peptide (PCIII) were detected by radioimmunoassay. Hepatic fibrosis scoring grade was assessed through Van-Gieson staining and observed under light microscope. Protein expression levels of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor beta1 (TGFbeta1) were determined with immunohistochemical staining method. Messenger RNA (mRNA) levels of collagen type I and PCIII were detected by reverse transcription polymerase chain reaction.</p><p><b>RESULTS</b>Serum levels of HA (ng/L), LN (microg/L) and PCIII (ng/L) in pre- and post-treatment model groups were higher than those in normal control group (121.8+/-9.5 and 110.3+/-13.4 vs. 33.1+/-3.7, 85.7+/-12.1 and 78.2+/-7.9 vs. 37.1+/-6.3, 35.9+/-3.5 and 33.7+/-2.6 vs. 15.6+/-2.8, respectively, t > or = 9.41, P<0.05), and there was no significant difference between the two model groups. Concentrations of HA (55.8ng/L+/-7.2ng/L), LN (43.1microg/L+/-3.4microg/L) and PCIII (27.8ng/L+/-3.4ng/L) decreased significantly in octreotide-treated group, compared with those in model groups (t >or=2.76, P<0.05). With histological analysis, fibrotic scoring grade in octreotide-treated group was obviously ameliorated, compared with that in model groups (chi2 > or = 3.97, P<0.05). Imaging analysis revealed that alpha-SMA and TGFbeta1 immunohistological staining areas were markedly shrinked in octreotide-treated group (t > or = 2.47, P < 0.05). In two model groups, PCIII and type I mRNA levels significantly up-regulated as compared with those in normal group (t > or = 9.27, P<0.001), and they were inhibited by octreotide markedly (t > or = 2.47, P<0.05).</p><p><b>CONCLUSIONS</b>Octreotide can inhibit hepatic stellate cells transforming into myofibroblasts, down-regulate TGFbeta1, collagen type I and PCIII transcriptions, so that it has therapeutic effects on experimental hepatic fibrosis.</p>

Effects of fibrogenetic growth factors on migration of hepatic stellate cells / 中华消化杂志

Objective To investigate the impact of alterations within the space of Disse micro- environment on the migration of hepatic stellate cells(HSC) during the process of liver fibrosis,and to ex plore the novel mechanism of liver fibrosis from the view of cell migration.Methods A modified in vitro Boyden chamber system to partially mimic in vivo microenvironment of Disse space of normal and liver fibrosis was employed.The effects of fibrogenetic growth factors on the migration of HSC in liver fibrosis were observed via cell migration and cell proliferation experiments.Results Enhanced platelet-derived growth factor(PDGF)-BB,transforming growth factor(TGF)-?1 and/or epithelial growth factor(EGF) in liver fibrosis resulted in an increase in migratory capacity of activated HSC.The enhanced migration of HSCs induced by PDGF-BB was partially associated with their increased proliferation,while,TGF-?1 or EGF-induced migration was proliferation independent.The elevation of basic fibroblast growth factor (bFGF) or vascular endothelial growth factor(VEGF)during liver fibrosis had no effect on the migration of HSCs.Conclusions The study provides valuable insights into the role of space of Disse microenvironment in regulating HSC migratory behavior.TGF-?1,PDGF-BB and EGF,which increased in liver fibrosis, could induce the migration of activated HSC.However,bFGF or VEGF has no such kind of effect,al- though they also increased during liver fibrosis.

Expression and effect of secondary lymphoid tissue chemokine in experimental ulcerative colitis in rats / 中华消化杂志

Objective To investigate the expression and effect of secondary lymphoid tissue chemokine(SLC)in experimental ulcerative colitis(UC)in rats.Methods Thirty Spague-Dawley rats were divided into control group and UC group.SLC expression in colon tissues was detected by RT-PCR and immunohistochemistry,respectively.Results The transcriptional level of SLC in UC tissues was significantly higher than that in the control group(0.846?0.07 vs 0.312?0.12,P＜0.01).The positive expression of SLC was concentrated mainly on submucosa,and the positive rate of SLC protein expression in UC group significantly higher than that in control group(P＜0.01).Conclusion SLC overexpression could contribute to the pathological processes in UC rats,thus SLC may be an ideal ther- apeutic target for UC.