Nitric oxide synthase inhibitor attenuates intestinal damage induced by zinc deficiency in rats

A nitric oxide synthase (NOS) inhibitor, NG-nitro-L -arginine methyl ester (L-NAME), was given to zinc-deficient (ZD) rats to determine whether it prevents the intestinal damage usually observed under these conditions. Weanling male rats were given free access to a ZD diet (2 mg zinc/kg), whereas control rats including pair-fed (PF) and ad libitum consumption (AL) groups were given a zinc-supplemented (50.8 mg zinc/kg) diet for 4 wk. Half of the ZD rats received L-NAME (0.3 g/L in drinking water) for 3 wk starting at the wk 2 of the deficient period. Plasma zinc concentration in ZD rats was significantly lower (P < 0.05) than that of AL and PF rats. Administration of L-NAME did not alter this concentration. Intestinal zinc concentration did not differ among groups. However, metallothionein-1 (MT-1) mRNA level was significantly lower in the intestine of ZD rats than in AL or PF rats. Treatment of ZD rats with L-NAME did not affect this level. Intestinal microvascular permeability evaluated by Evans blue showed significantly higher extravasation in ZD rats than in AL rats, whereas L-NAME administration inhibited the extravasation. Expression of inducible NOS mRNA was observed in intestine of ZD but not of AL or PF rats, and there was no significant difference between ZD rats, regardless of L-NAME treatment. The activity ratio of inducible NOS to total NOS in ZD rats not receiving L-NAME was significantly higher than that in AL rats or ZD rats treated with L-NAME (P < 0.05). The number of apoptotic-positive and goblet cells in intestinal villi was significantly higher in ZD rats compared with AL or PF rats. L-NAME administration in ZD rats reversed this effect. These results indicate that inhibition of NOS ameliorates zinc deficiency-induced intestinal damage in rats.     

Nitric oxide synthase inhibitors reduced lipid peroxidation in N-nitrosodiethylamine-treated rats

Studies were carried out to examine the anti-oxidative activity of nitric oxide synthase (NOS) inhibitors including L-N omega-nitro-L-arginine methyl ester (L-NAME) and spermidine in rats pretreated per os with N-nitrosodiethylamine (NDEA) (0.1 mg/kg b.w.) daily for 30 days. Both L-NAME and/or sapermidine were gavaged to animals in a daily dosage of 10 mg/kg body weight, however, the polyamine was applied for the first 21 days only, and further L-NAME was employed for 3 days (day 22, 23 and 24). Saline treated rats were served as control. The results of this experiment showed that NDEA increased TBARS in the liver and small intestine of rats, and the agent did not have any effect(s) in spleen and kidney, respectively. Pretreatment of animals with spermidine and/or L-NAME significantly (p < 0.05) lowered lipid peroxidation in NDEA-treated rats. The finding described here elucidate that both L-NAME and spermidine play an important anti-oxidative role in NDEA-mediated lipid peroxidation and/or pro-oxidant shift(s) in rats.     

一氧化氮与矽肺早期炎性损伤

综述了一氧化氮 (NO)参与矽肺损伤的细胞和分子机制。大量资料表明 ,NO与矽肺的形成有关。作为一种自由基 ,NO不仅损伤肺组织 ,而且与超氧阴离子结合 ,形成毒性更强的过氧亚硝酸阴离子 ,它通过不同机制在肺内产生广泛的细胞毒性。NO的产生需要细胞因子的存在。NF κB在诱导型一氧化氮合酶基因表达过程中的作用尤其重要。有关NO在NF κB激活过程中的作用 ,目前文献报道存在分歧     

一氧化氮和一氧化氮合酶对雄性生殖系统的作用

一氧化氮(NO)是一种兼有第二信使、神经递质和效应分子等多种生理功能的生物信号分子,在生物体内发挥着十分重要的生理作用。NO的产生离不开一氧化氮合酶(NOS),NOS广泛分布于男性生殖系统的各个器官,对生殖的调节作用具有双重性。本文就NO和NOS对雄性生殖系统的作用作一简要概述。     

Nitric oxide synthase in diabetic rat testicular tissue and the effects of pentoxifylline therapy

Diabetes is known to be associated with erectile dysfunction, retrograde ejaculation, level of testicular hormone, and a decrease in semen quality, respectively. In this project, we aimed to investigate at the molecular level, the effects of NOS on testes pathology in diabetes and examine the effects of pentoxifylline on healing. A total of 50 Wistar albino male rats were divided into five groups: Group I control; Group II only diabetes; Group III and IV diabetes?+?pentoxifylline; Group V only pentoxifylline. Group III rats received 50?mg/kg/day pentoxifylline during two months. In comparison, Group IV rats received saline in the first month followed by 50?mg/kg/day of pentoxifylline for the following month. NOS expression in testicular tissue was assessed using qRT-PCR, western blot, and immunohistochemistry. The mean seminiferous tubule diameter, Johnsen's testicular biopsy score, and serum testosterone levels decreased compared to controls. In contrast, the number of apoptotic cells, the levels of nNOS, iNOS and eNOS mRNA, and protein increased when compared to the control. Upon pentoxifylline therapy NOS decreased suggesting that it contributes to this damage and treatment with pentoxifylline may be effective in reversing this damage.     

Enzyme activities in the epidermis of zinc-deficient rats.

Fifteen enzymes participating in epidermal energy metabolism in zinc-deficient and -supplemented rats were assayed utilizing fluorometric microchemical techniques. In the zinc-deficient group, the activities of six enzymes catalyzing glycolysis decreased by 30 to 50% of the control; the most dramatic decreases were found in phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase. Zinc deficiency caused a 31% decrease in the activity of glucose-6-phosphate dehydrogenase, a 63% decrease in fumarate hydratase, a 46% decrease in glutamate dehydrogenase, and a 30 to 40% decrease in aminotransferases.     

NOS在子宫内膜异位症患者在位内膜和异位内膜中的表达

目的:探讨一氧化氮合酶(NOS)在子宫内膜异位症患者在位内膜和异位内膜中的表达。方法:采用逆转录聚合酶链式反应(RT-PCR)方法对20例正常子宫内膜和30例子宫内膜异位症患者在位和异位内膜进行内皮型NOS(eNOS)和诱导型NOS(iNOS)表达的半定量检测。结果:eNOS在子宫内膜的增生期和分泌期均有表达,增生期在位内膜为2.47±0.38,异位内膜为2.53±0.51,对照组为1.73±0.50,分泌期在位内膜为3.37±0.41,异位内膜为3.43±0.44,对照组为3.16±0.55,增生期eNOS的表达均高于对照组(P=0.01),分泌期eNOS的表达无统计学意义(P=0.064)。iNOS只在子宫内膜的分泌期有微量表达,在位内膜为1.17±0.22,异位内膜为1.33±0.28,对照组为0.86±0.24,分泌期iNOS的表达与对照组相比有统计学意义(P=0.016)。在位内膜和异位内膜中eNOS和iNOS的表达在月经各周期相比较均无统汁学意义(P值分别为0.25、0.106、0.073)。结论:NOS在子宫内膜异位症患者子宫内膜上的高表达可能与其发病机制存在一定的关系。     

Prouroguanylin overproduction and localization in the intestine of zinc-deficient rats

Identification of the upregulation of preprouroguanylin mRNA in the rat small intestine during zinc deficiency provides a potential mechanistic link between production of the intestinal hormone uroguanylin and the diarrhea that may accompany zinc deficiency. In the current study, in situ hybridization demonstrated that the number of preprouroguanylin mRNA-expressing cells was significantly higher in zinc-deficient rats than in zinc-adequate rats. Immunohistochemical studies, with a uroguanylin peptide affinity-purified antibody, demonstrated that immunoreactivity was localized to the tips of villi of the duodenum and jejunum in zinc-adequate rats. However, positive cells were scattered throughout the villus of zinc-deficient rats. A subset of cells, perhaps enterochromaffin cells, exhibited the predominant staining, whereas no specific staining was found in goblet cells or lymphocytes of the lamina propria. Western blotting demonstrated that the expression of prouroguanylin in both duodenum and jejunum was elevated by dietary zinc depletion. These results show that dietary zinc deficiency upregulates prouroguanylin in intestinal cells, which is consistent with a role for uroguanylin in the etiology of diarrhea observed in human zinc deficiency.     

Zinc bioavailability is improved by the micronised dispersion of zinc oxide with the addition of L-histidine in zinc-deficient rats

Zinc fortification of milk or soft drinks is usually used to combat zinc deficiencies in developing countries. Water-soluble zinc compounds, such as zinc sulfate or zinc citrate, are better absorbed but have an unacceptable taste. A micronised, dispersible zinc oxide (MDZnO), which does not have such a problem concerning taste, had higher solubility compared to ZnO (zinc oxide) in an artificial gastric solution. MDZnO was tested for its bioavailability using zinc-deficient Wistar rats. Prior to the experiment, rats were fed zinc-deficient diet for 3 wk and were orally administered control (distilled water) or zinc solutions (ZnO, ZnO+L-histidine (His), MDZnO, MDZnO+His, 1 mg zinc/kg or 3.2 mg His/kg body weight). Compared to ZnO, MDZnO showed a lag in peak time and a lengthy period of continued high plasma zinc concentration after the single oral administration of zinc compounds. Addition of His to MDZnO elevated serum zinc concentration. Serum zinc concentration (area under the curve) in rats administered MDZnO with His was significantly higher than in rats administered distilled water (p<0.05). Liver zinc level was significantly higher in rats administered MDZnO with His compared with control rats (p<0.05), although the level was not affected by the administration with ZnO alone, ZnO+His, or MDZnO alone. In conclusion, the solubility of ZnO was elevated by the micronised dispersion tecnique and an in vivo study using zinc-deficient rats confirmed that its bioavailability was significantly improved compared to ZnO and the coadministration of His additively enhanced the bioavailability of MDZnO.     

Nitric oxide synthase inhibition delays low-frequency stimulation-induced satellite cell activation in rat fast-twitch muscle

This study examined the effect of nitric oxide synthase (NOS) inhibition via N(ω)-nitro-l-arginine methyl ester (l-NAME) administration on low-frequency stimulation-induced satellite cell (SC) activation in rat skeletal muscle. l-NAME only delayed stimulation-induced increases in SC activity. Also, stimulation-induced increases in hepatocyte growth factor (HGF) mRNA and protein expression were only abrogated at the mRNA level in l-NAME-treated animals. Therefore, early stimulation-induced SC activation appears to be NOS-dependent, while continued activation may involve NOS-independent HGF translational control mechanisms.     

甲醛对大鼠肺组织一氧化氮和一氧化氮合酶的影响

选择Wistar大鼠40只,随机分为4组:甲醛低剂量组(2.5mg/m3)、中剂量组(5mg/m3)、高剂量组(10mg/m3)、对照组,每组10只。除对照组外,其余3组每日吸入甲醛1次,每次4h,连续9周。测定染毒组大鼠肺组织中NO含量及NOS活性降低,与对照组比较差异有显著性(P<0.05或P<0.01)。说明甲醛可能对大鼠肺组织NOS表达有抑制作用。     

Short-term effect of the HMG-CoA reductase inhibitor rosuvastatin on erythrocyte nitric oxide synthase activity

Prevention and treatment of cardiovascular disorders by HMG-CoA reductase inhibitors (or statins), beyond their lipid-lowering properties, have been demonstrated including activation of the endothelial nitric oxide synthase (eNOS). Beside endothelial cells, red blood cells (RBCs) possess NOS and produce nitric oxide (NO), which contributes to RBC deformability. The present study tested the capacity of statins to activate NOS in RBCs and subsequently to modulate RBC deformability in vitro. Blood samples of healthy young volunteers were incubated with or without rosuvastatin. Afterwards RBC-NOS activity and RBC deformability were determined. Rosuvastatin incubation significantly increased NOS phosphorylation, NOS dependent NO-formation, and RBC deformability. The NOS inhibitor NG- monomethyl-L-arginine reversed the stimulatory effect of rosuvastatin on RBC-NOS activity. This NO dependent effect of rosuvastatin might have an important influence on microcirculation and may offer new perspectives for the therapeutic use of statins.     

Intestinal cellular proliferation and protein synthesis in zinc-deficient rats

Immature male Wistar rats were given a low-zinc semi-synthetic diet (2 mg Zn/kg) for 28 d. Control groups received a similar diet supplemented with 58 mg Zn/kg either ad lib. or in amounts matched to the consumption of the Zn-deficient group. Rates of growth, food consumption and small intestinal length were significantly reduced in the Zn-depleted rats. Zn deficiency in the rat was associated with a reduction in the ratio, crypt: villus and a lower rate of crypt cell division in the jejunum. This resulted in a substantial decrease in the net influx of new cells into the villi of the Zn-deficient animals compared with controls. The fractional rates of protein synthesis in jejunal mucosa were measured by a technique based on the determination of L-[4-3H]phenylalanine incorporation. There was no evidence of a decline in the protein synthetic rate in total mucosa from Zn-deficient rats. It is suggested that a reduction in cell influx into the villi may be responsible for the morphological and functional changes observed in the small intestine of rats fed on a low-Zn diet.