AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible i...AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible isoforms.The inducible isoforms (iNOS and COX-2) are of great interest as regulators of tumor angiogenesis,tumorigenesis and inflammatory processes.This study was to clarify their role in pancreatic adenocarcinomas. METHODS:We investigated the immunohistochemical iNOS and COX-2 expression in 40 pancreatic ductal adenocardnomas of different grade and stage.The results were compared with microvessel density and dinicopathological data. RESULTS:Twenty-one (52.5%) of the cases showed iNOS expression,15 (37.5%) of the cases were positive for COX-2. The immunoreaction was heterogeneously distributed within the tumors.Staining intensity was different between the tumors.No correlation between iNOS and COX-2 expression was seen.There was no relationship with microvessel density. However,iNOS positive tumors developed more often distant metastases and the more malignant tumors showed a higher COX-2 expression.There was no correlation with other clinicopathological data. CONCLUSION:Approximately half of the cases expressed iNOS and COX-2.These two enzymes do not seem to be the key step in angiogenesis or carcinogenesis of pancreatic adenocarcinomas.Due to a low prevalence of COX-2 expression,chemoprevention of pancreatic carcinomas by COX-2 inhibitors can only achieve a limited success.展开更多
AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis.METHODS: Healthy adult Sprague-Dawlay (SD) rats of bo...AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis.METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280±30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg.kg-1 and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28th day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E2(PGE2), nitric oxide (NO), as well as the iNOS and COX-2expression were also determined biochemically or immunohistochemically.RESULTS: CDMI increased to 2.87±0.64 and 3.12±1.12respectively in rats treated with acetic acid and TNBS enema,which was in accordance with the significantly elevated colonic NO and PGE2 contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg@kg-1, CDMI in both models of rat colitis was significantly decreased (P＜0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE2 content, as well as the down-regulated expression of colonic iNOS and COX-2.CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.展开更多
OBJECTIVE： Buckwheat has been considered as a potential source of nutraceutical components on the world market of probiotic foodstuffs. The purpose of this study was to evaluate the effects of tartary buckwheat （Fag...OBJECTIVE： Buckwheat has been considered as a potential source of nutraceutical components on the world market of probiotic foodstuffs. The purpose of this study was to evaluate the effects of tartary buckwheat （Fagopyrum tataricum） sprouts on oxidation and pro-inflammatory mediators. METHODS： The anti-oxidant effects of buckwheat extract （BWE） and rutin were evaluated by using 1,1-diphenyl-2-picrylhydrazyl （DPPH）-and nitric oxide （NO）-scavenging activities, serum peroxidation and chelating assays. Lipopolysaccharide （LPS）-stimulated RAW264.7 cells were used to evaluate anti-inflammatory activities of buckwheat and rutin. NO production in LPS- stimulated RAW264.7 cells was determined by using Griess reagent. The expressions of inducible nitric oxide synthase （iNOS）, cyclooxygenase-2 （COX-2）, nuclear factor-kappa B （NF-κB） p65 subunit in cytosolic and nuclear portions were determined by Western blot analysis. Also, the production of inflammatory cytokines interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） was determined by enzyme-linked immunosorbent assay. RESULTS： Inhibitory concentration 50 values for DPPH- and NO-scavenging activities of BWE were 24.97 and 72.54 μg/mL respectively. BWE inhibited serum oxidation and possessed chelating activity. Furthermore, BWE inhibited IL-6 and TNF-a production in LPS-stimulated RAW264.7 cells. Also, BWE inhibited iNOS and COX-2 expression and NF-KB p65 translocation. CONCLUSION： Buckwheat sprouts possessed strong antioxidant activity and inhibited production of pro-inflammatory mediators in the applied model systems. Thus, buckwheat can be suggested to be beneficial in inflammatory diseases by inhibiting the free radicals and inflammatory mediators.展开更多
文摘AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible isoforms.The inducible isoforms (iNOS and COX-2) are of great interest as regulators of tumor angiogenesis,tumorigenesis and inflammatory processes.This study was to clarify their role in pancreatic adenocarcinomas. METHODS:We investigated the immunohistochemical iNOS and COX-2 expression in 40 pancreatic ductal adenocardnomas of different grade and stage.The results were compared with microvessel density and dinicopathological data. RESULTS:Twenty-one (52.5%) of the cases showed iNOS expression,15 (37.5%) of the cases were positive for COX-2. The immunoreaction was heterogeneously distributed within the tumors.Staining intensity was different between the tumors.No correlation between iNOS and COX-2 expression was seen.There was no relationship with microvessel density. However,iNOS positive tumors developed more often distant metastases and the more malignant tumors showed a higher COX-2 expression.There was no correlation with other clinicopathological data. CONCLUSION:Approximately half of the cases expressed iNOS and COX-2.These two enzymes do not seem to be the key step in angiogenesis or carcinogenesis of pancreatic adenocarcinomas.Due to a low prevalence of COX-2 expression,chemoprevention of pancreatic carcinomas by COX-2 inhibitors can only achieve a limited success.
文摘AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis.METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280±30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg.kg-1 and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28th day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E2(PGE2), nitric oxide (NO), as well as the iNOS and COX-2expression were also determined biochemically or immunohistochemically.RESULTS: CDMI increased to 2.87±0.64 and 3.12±1.12respectively in rats treated with acetic acid and TNBS enema,which was in accordance with the significantly elevated colonic NO and PGE2 contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg@kg-1, CDMI in both models of rat colitis was significantly decreased (P＜0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE2 content, as well as the down-regulated expression of colonic iNOS and COX-2.CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.
文摘OBJECTIVE： Buckwheat has been considered as a potential source of nutraceutical components on the world market of probiotic foodstuffs. The purpose of this study was to evaluate the effects of tartary buckwheat （Fagopyrum tataricum） sprouts on oxidation and pro-inflammatory mediators. METHODS： The anti-oxidant effects of buckwheat extract （BWE） and rutin were evaluated by using 1,1-diphenyl-2-picrylhydrazyl （DPPH）-and nitric oxide （NO）-scavenging activities, serum peroxidation and chelating assays. Lipopolysaccharide （LPS）-stimulated RAW264.7 cells were used to evaluate anti-inflammatory activities of buckwheat and rutin. NO production in LPS- stimulated RAW264.7 cells was determined by using Griess reagent. The expressions of inducible nitric oxide synthase （iNOS）, cyclooxygenase-2 （COX-2）, nuclear factor-kappa B （NF-κB） p65 subunit in cytosolic and nuclear portions were determined by Western blot analysis. Also, the production of inflammatory cytokines interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） was determined by enzyme-linked immunosorbent assay. RESULTS： Inhibitory concentration 50 values for DPPH- and NO-scavenging activities of BWE were 24.97 and 72.54 μg/mL respectively. BWE inhibited serum oxidation and possessed chelating activity. Furthermore, BWE inhibited IL-6 and TNF-a production in LPS-stimulated RAW264.7 cells. Also, BWE inhibited iNOS and COX-2 expression and NF-KB p65 translocation. CONCLUSION： Buckwheat sprouts possessed strong antioxidant activity and inhibited production of pro-inflammatory mediators in the applied model systems. Thus, buckwheat can be suggested to be beneficial in inflammatory diseases by inhibiting the free radicals and inflammatory mediators.
