【Abstract】ObjectiveTo investigate the protective effect of melatonin on renal injury induced by bile duct ligation in rats. MethodsSixtyfour rats were randomly divided into four experimental groups (n=16 rats per group): the control group (CN), sham operative group (SO), bile duct ligation group (BDL) and bile duct ligation melatonin treatment group (BDL+Mel). Obstructive jaundice was induced by common bile duct ligation. Plasma level of nitric oxide (NO), total bilirubin (TB), direct bilirubin (DB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen (BUN) and creatinine (Cr) were measured 4 d and 8 d after operation. NO and inducible nitric oxide synthase (iNOS) in renal tissue were detected at the same time point, too. Histopathological changes of kidneys were examined by HE staining. ResultsIn BDL group, the plasma levels of NO, TB, DB, ALT, AST, BUN and Cr were higher than those of SO group (P＜0.01）, and the level of NO and activities of iNOS in renal tissue were significantly increased (P＜0.01）. However, in BDL+Mel group, the plasma levels of NO, ALT, AST, BUN and Cr were lower than those of the BDL group (P＜0.01）, and the level of NO and activities of iNOS in renal tissue were significantly suppressed (P＜0.01）; histopathological changes of kidneys were improved.ConclusionAugmentation of iNOS activities and increasing of NO production in local tissue contributed to renal injury induced by bile duct ligation, and the mode of melatonin’s protective actions, at least in part, relates to interference with no pathways.
Objective To study the expression of inducible nitric oxide synthase (iNOS)，endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) in human gastric cancer and their relationship with tumor angiogenesis and to investigate the interaction of NOS and VEGF in gastric cancer. Methods The expression and distribution of VEGF, iNOS and eNOS in 34 gastric cancer specimens were detected with immunohistochemistry. Microvessel density (MVD) was counted with FⅧRAg immune specific staining. Results The expression rates of iNOS, eNOS and VEGF in 34 gastric cancers were 73.5%, 82.4% and 91.2% respectively. The expression of VEGF had a significant positive relation with iNOS, but not with eNOS. The MVDs of VEGF or iNOS positive gastric cancers were obviously higher than those of VEGF or iNOS negative gastric cancers. There was no significant difference between the MVDs of eNOS positive gastric cancers and eNOS negative ones. Conclusion MVD increases with increase of expression of VEGF and iNOS in gastric cancer. It is indicated that VEGF and iNOS can promote gastric cancer angiogenesis. VEGF and iNOS have a significant positive correlation, which suggests that in human gastric cancer, iNOS plays an important role in the production and action of VEGF.
【Abstract】Objective To study the effects of nitric oxide (NO) on the growth and metastasis of tumor.Methods The literatures of recent years were reviewed.Results NO had double effects on the growth and metastasis of tumor. NO promoted the growth and metastasis by regulating the expression of tumor proliferation gene and inducing tumor angiogenesis. On the other hand, NO had antitumor effects by interfering with the metabolism of tumor cells, inducing the damage of DNA, forming high toxic free radical, inducing apoptosis of tumor cells and mediating the antitumor action of endothelial cells and macrophages.Conclusion Selective blockage or induction of synthesis of NO may be a new way for tumor therapy.
ObjectiveTo study the change and significance of the serum nitric oxide (NO) level in patient with obstructive jaundice complicated with renal dysfunction. MethodsThe level of NO, BUN, Cr in serum and the activity of NOS in 25 patients with obstructive jaundice and renal dysfunction and 26 healthy adults was studied.ResultsThe patients’ serum NO level and the activity of NOS were significantly lower than those in the control group(P＜0.01)，whereas the serum BUN and Cr levels were significantly higher than those in control group(P＜0.01). The linear correlation analysis showed that the serum NO had a negative correlation between serum BUN and Cr level (P＜0.01). ConclusionThe patients with obstructive jaundice and renal dysfunction may lead to the decrease of serum NO level. NO may have some protective effects to the renal function during obstructive jaundice.
ObjectiveTo study the effects of aminoguanidine (AG), a selective inhibitor of inducible nitric oxide synthase (iNOS) on the pathological changes of liver tissues and ultrastructural changes of liver cells in rodent model of endotoxic shock. MethodsTwentyfour male Wistar rats were randomly divided into normal control group，lipopolysaccharide (LPS) control group and AG treatment group, each group had 8 rats. Rats were challenged by E.coli LPS to set up the model of endotoxic shock, AG group were treated by aminoguanidine. The pathological and ultrastructural changes of liver tissues and plasma NO contents of three groups were observed and compared. ResultsLight microscopy revealed that many tiny abscesses scattered in liver tissue in LPS group, accompanied by necrosis of liver cells and neutrophils infiltration, while liver injuries of AG group were much slighter than that in LPS group. Electron microscopy revealed that there were dissolved plaques in hepatocyte nuclears, swelling of mitochondria, decreasing in number of mitochondrial ridges, while AG play a protective role to nuclears and mitochondria of hepatocytes. The plasma NO levels of LPS control group were higher than that of normal control group, and plasma NO levels decreased significantly after AG treatment, but still higher than that of normal control group. Conclusion Aminoguanidine selectively inhibits iNOS activity and prevents the overproduction of NO induced by iNOS, thus attenuates the damages of liver structure induced by NO. This method has potential value in clinical application, which deserves more deep research.
Objective To study the changes of endothelin (ET) and nitric oxide (NO) in the local site of vein transfer with delayed breaking pedicle and the relation with vasospasm and vein transfer in rabbits. MethodsThe ET concentration of blood was determined with the radioimmunoassay method. The plasma NO-2,NO-3 levels in the local site of vein transfer with delayed breaking pedicle, which reflected NO levels indirectly, were detected with Ultravioletvisible (UvVIS ) spectrophotometer. ResultsThe endothelin concentration of blood was increased significantly at 2, 4 hour after the operation (P＜0.01), and at 8 hour after the operation (P＜0.05). The plasma NO level was significantly decreased at 2, 4 hour after the operation (P＜0.01). But at 24 hour after the operation, the plasma NO level was increased significantly (P＜0.05). Conclusion The recovery of ET concentration of blood and the increase of plasma NO at 24 hour after the operation are the cause of the reduced incidence of vascular crisis of vein transfer with delayed breaking pedicle, and the very time point is the optimum moment for pedicle breaking.
Objective To investigate the effect of nitric oxide (NO) on the renal function in acute biliary infection. Methods 35 Wistar rats were divided randomly into acute biliary infection group (AC), group of AC with Larginine(L), group of L-NAME(N), group of simple biliary obstruction(O) and a sham-operated group(SO), and serum NO、 BUN、 Cr and NOS were determined and pathologic changes of liver and kidney were observed. Results NO and NOS were significantly higher in L group than in any other groups (P＜0.05), BUN and Cr were significantly lower than in AC and N groups (P＜0.05), but showed no significance compared with O group (P＞0.05). The pathology of kidney in L group showed a less severe change than that in AC group; NO and NOS in N group were lower than those in other groups. BUN and Cr were higher than those in other groups (P＜0.05). Conclusion NO has a protection for renal function in acute biliary infected rats the mechanism being related to its dilative effect on renal vessels and increased renal blood perfusion.
ObjectiveTo explore the effect of endotoxin on insulin secretion from islet βcell of rat pancreas.MethodsAfter the model of endotoxemia was established in rats with intraperitoneal injection of LPS (2 mg/kg),the changes of insulin level in the serum and pancreas were dynamically determined, the expression of inducible nitric oxide synthase (iNOS) by situ hybridization and DNA damage in islet cells were also observed, the effect of sodium nitroprusside (exogenous NO) on synthesis and secretion of insulin from isolated islet βcell of normal rat pancreas under high glucose stimulation was also evaluated.ResultsThe level of glucose and insulin in plasma were significantly increased at 12th and 6th h, respectively and kept on 3 d after injection of LPS,but the insulin level in pancreas was not remarkably altered.The expression of iNOS and DNA damaged significantly enhanced at 6 d after endotoxemia. The high glucosestimulated insulin synthesis and secretion were bly inhibited by exogenous NO.ConclusionThese findings suggest that LPS be stimulate the expression of iNOS and NO product,which inhibites synthesis and secretion of insulin in islet βcells,but it stimulates insulin secretion by another mechanism,and results in dysfunction and destruction of the rat pancreas.
ObjectiveTo understand the effect of nitric oxide (NO) on the formation of hyperdynamic circulatory syndrome (HCS) and the influence of level of NO on HCS. MethodsAfter establishment of stable HCS in partial portal vein ligated rats,the quantity of NO in blood of portal vein and the activity of nitric oxide synthase (NOS) in liver were determined by pre and post injection of inhabitor of NOS (NGmethylLarginine) and hemodynamics was supervised simultaneously.ResultsThe quantity of NO was paralleled with the activity of NOS and was elevated markedly by 24 hours after operation and reached the top by 48 hours after surgery. These sequential changes were coincided with the dilation of general vascularture. There was a close relation between this changes and the formation of HCS.The quantity of NO and the activity of NOS were decreased significantly to the level of the control group after injection of NGmethylLarginine (LNMMA). LNMMA inhabited the activity of NOS and blocked the production of NO. HCS ameliorated obviously. ConclusionNO plays an important role in initiating the dilation of general vascularture and plays a critical role in the formation of HCS. HCS will be ameliorated obviously or be blocked completely by eliminating the effect of NO and the portal pressure will decreased significantly or recover to normal range.
The aim of this study is to assess ischemia/reperfusion injury in carbon tetrachloride induced cirrhotic liver as compared to normal liver in the rats. Results showed that in cirrhotic liver, instead of diminishing the hepatic vein nitric oxide level increased significantly after ischemia from 8.04 μmol/L to 11.52 μmol/L and remained high till 5 hrs after reperfusion. The hepatic adenosine triphosphate (ATP) contents decreased as that seen in normal rat but did not restore to normal till the end of 5 hrs after reperfusion. Based on these findings, it is postulated that in cirrhotic liver, ischemia/reperfusion injury is aggrvated as evidenced by of nitric oxide, and extended diminishing in ATP.