Imbalanced free radicals and antioxidant defense systems in schizophrenia:A comparative study

Objective: To examine changes of blood oxidative-antiovidative level in schizophrenic patients and its relationship with clinical symptoms. Methods: Forty-six Chinese patients met DSM-IV (Diagnostic and Statistical Manual of Mental Disor- ders-IV) criteria for schizophrenia and fifty age- and sex-matched healthy controls were enrolled in the present study. Baseline psychiatric symptom severity was assessed with brief psychiatric rating scale, positive and negative syndrome scale on the blood draw day. Fresh blood samples were collected to measure levels of nitric oxide and lipid peroxide in plasma as well as activities of superoxide dismutase, catalase and glutathione peroxidase in red blood cells by spectrophotometric assays simultaneously. Results: Comparison of the biochemical parameters indicated that the level of nitric oxide and lipid peroxide increased in patient group, which represented a positive correlation with positive scale scores; while the activities of three critical enzymes decreased and showed a negative linear correlation. Conclusion: This study showed that there are dysregulation of free radical metabolism and poor activities of the antioxidant defense systems in schizophrenic patients. Excess free radicals formation may play a critical role in the etiology of schizophrenia. Using antioxidants might be an effective therapeutic approach to partially alleviate or prevent the symptoms of schizophrenia.

Interplay between nitric oxide and VIP in CCK-8-induced phasic contractile activity in the rabbit sphincter of Oddi

AIM: The sphincter of Oddi (SO) plays an important role in delivery of bile into the duodenum. To establish whether vasoactive intestinal polypeptide (VIP) and nitric oxide (NO) were involved in phasic contractile activity of the rabbit SO stimulated by cholecystokinin-octapeptide (CCK-8). METHODS: Isolated SO muscle rings were cleaned of fat and mounted horizontally on two small L-shaped hooks one of which was connected to a force transducer for the measurement of isometric tension.The experiments were carried out in a thermostatically controlled (37±0.2℃) organ bath (5 mL) containing Krebs solution.The organ fluid was gassed with 95% O2 and 50 mL/L CO2 to keep the pH at 7.40±0.05. Contractile responses to CCK-8 (1 μmol/L) were evaluated in the presence and absence of NG-nitro-L-arginine (LNNA), an inhibitor of NO synthase (100 μmol/L), and (p-chloro-D-Phe6-Leu17)-VIP (VlPa, 30 μmol/L), a VIP receptor antagonist. RESULTS: CCK-8 stimulated the phasic activity of the SO. NO synthase inhibition increased the frequency and amplitude of contractions with a slight increase in developed tension. Pre-incubation with VlPa also attenuated this CCK-8 effect. The combined application of LNNA and VlPa abolished the phasic activity of the muscle rings with a marked increase in tension in response to CCK-8. CONCLUSION: VIP and NO together contribute to an increase in phasic activity of SO.

Changes of nitric oxide and endothelin, thromboxane A2 and prostaglandin in cirrhotic patients undergoing liver transplantation

AIM： To investigate the perioperative changes of nitric oxide （NO） and endothelin （ET）, thromboxane A2 （TXA2） and prostaglandin （PGI2） during liver transplantation in end-stage liver disease patients. METHODS： Twenty-seven patients with end-stage cirrhosis undergoing liver transplantation were enrolled in this prospective study. Blood samples were obtained from superior vena at five different surgical stages. Plasma concentrations of nitrate and nitrite were determined to reflect plasma NO levels. Plasma levels of ET-1, 6-keto-PGF1 alpha and thromboxane B2 （TXB2）, the latter two being stable metabolites of PGI2 and TXA2 respectively, were measured.RESULTS： The NO level decreased significantly after vascular cross-clamping and increased significantly at 30 rain after reperfusion. While the ET levels at 30 rain after clamping and after reperfusion were significantly elevated. The ratio of NO/ET decreased significantly at 30 rain after vascular cross-clamping and at the end of surgery. The PGI2 level and the TXA2 during liver transplantation were significantly higher than the baseline level, but the ratio of TXA2/PGI2 decreased significantly at 30 rain after clamping. CONCLUSION： NO/ET and TXA2/PGI2 change during liver transplantation. Although the precise mechanism remains unknown, they may play a role in the pathobiology of a variety of liver transplant-relevant processes.

Glutamine prevents oxidative stress in a model of portal hypertension

To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL). METHODSMale Wistar rats were housed in a controlled environment and were allowed access to food and water ad libitum. Twenty-four male Wistar rats were divided into four experimental groups: (1) control group (SO) - rats underwent exploratory laparotomy; (2) control + glutamine group (SO + G) - rats were subjected to laparotomy and were treated intraperitoneally with glutamine; (3) portal hypertension group (PPVL) - rats were subjected to PPVL; and (4) PPVL + glutamine group (PPVL + G) - rats were treated intraperitoneally with glutamine for seven days. Local injuries were determined by evaluating intestinal segments for oxidative stress using lipid peroxidation and the activities of glutathione peroxidase (GPx), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) after PPVL. RESULTSLipid peroxidation of the membrane was increased in the animals subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL procedure showed levels of lipid peroxidation similar to those of the control groups (P > 0.05). The activity of the antioxidant enzyme GTx was decreased in the gut of animals subjected to PH compared with that in the control group of animals not subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL showed similar GTx activity to both the control groups not subjected to PH (P > 0.05). At least 10 random, non-overlapping images of each histological slide with 200 × magnification (44 pixel = 1 μm) were captured. The sum means of all areas, of each group were calculated. The mean areas of eNOS staining for both of the control groups were similar. The PPVL group showed the largest area of staining for eNOS. The PPVL + G group had the second highest amount of staining, but the mean value was much lower than that of the PPVL group (P < 0.01). For iNOS, the control (SO) and control + G (SO + G) groups showed similar areas of staining. The PPVL group contained the largest area of iNOS staining, followed by the PPVL + G group; however, this area was significantly smaller than that of the group that underwent PH without glutamine (P < 0.01). CONCLUSIONTreatment with glutamine prevents gut mucosal injury after PH in rats.

Polypeptide from Chlamys farreri inhibits UVB-induced apoptosis of HaCaT cells via iNOS/NO and HSP90

Polypeptide from Chlamys farreri(PCF) is a novel marine bioactive product that was isolated from the gonochoric Chinese scallop Chlamys farreri,and was found to be an effective antioxidant in our recent studies.In this study,we investigated the effect of PCF on ultraviolet B(UVB)-induced apoptosis of HaCaT cells and the intracellular signaling pathways involved.Pretreatment with the inducible nitric oxide synthase(iNOS) inhibitor S-methylisothiourea sulfate inhibited UVB-induced apoptosis,indicating that iNOS and NO play important roles in apoptosis.On the other hand,the inhibition of UVB-induced apoptosis in the immortalized keratinocyte(HaCaT) cells by PCF was estimated using a DNA ladder.PCF treatment inhibited UVB-induced iNOS activation,as determined by RT-PCR,NO production,as determined by ESR,and up-regulated heat shock protein(HSP) 90 activation,as determined by Western blotting.Our results indicate that iNOS and NO are involved in UVB-induced apoptosis of HaCaT cells and the protective effect of PCF against UVB irradiation is exerted by suppressing the expression of iNOS,followed by inhibition of NO release and enhanced activation of HSP90.

Hepatotropic growth factors protect hepatocytes during inflammation by upregulation of antioxidative systems

AIM:To investigate effects of hepatotropic growth factors on radical production in rat hepatocytes during sepsis.METHODS:Rat hepatocytes,isolated by collagenase perfusion,were incubated with a lipopolysaccharide(LPS)-containing cytokine mixture of interleukin-1β,tumor necrosis factor-α and interferon-γ to simulate sepsis and either co-incubated or pre-incubated with hepatotropic growth factors,e.g.hepatocyte growth factor,epidermal growth factor and/or transforming growth factor-α.Cells were analyzed for glutathione levels.Culture supernatants were assayed for produc-tion of reactive oxygen intermediates(ROIs) as well as NO2-,NO3-and S-nitrosothiols.To determine cellular damage,release of aspartate aminotransferase(AST) into the culture medium was analyzed.Activation of nuclear factor(NF)-κB was measured by electrophoretic mobility shift assay.RESULTS:Rat hepatocytes treated with the LPS-containing cytokine mixture showed a significant increase in ROI and nitrogen oxide intermediate formation.AST leakage was not significantly increased in cells treated with the LPS-containing cytokine mixture,independent of growth-factor co-stimulation.However,pretreatment with growth factors significantly reduced AST leakage and ROI formation while increasing cellular glutathione.Application of growth factors did not result in increased NF-κB activation.Pretreatment with growth factors further increased formation of NO2-,NO3-and S-nitrosothiols in hepatocytes stimulated with LPS-containing cytokine mixture.Thus,we propose that,together with an increase in glutathione increased NO2-,NO3-formation might shift their metabolism towards non-toxic products.CONCLUSION:Our data suggest that hepatotropic growth factors positively influence sepsis-induced hepatocellular injury by reducing cytotoxic ROI formation via induction of the cellular protective antioxidative systems.

EFFECT OF ACUPUNCTURE OF "ZUSANLI" AND "WEISHU" ACUPOINTS ON EXPERIMENTAL GASTRIC ULCER

Objective: To observe the therapeutic effect of electroacupuncture (EA) of "Zusanli"(ST 36) and "Weishu"(BL 21)on the experimental gastric ulcer in Xu period of a day for analyzing the best opportunity of acupuncture treatment of gastric ulcer. Methods:49 Wistar rats were randomly divided into ① control group, ② ST 36 Xu group, ③ BL 21 Xu group, ④ ST 36 Chen group, ⑤ BL 21 Chen group, ⑥ ST 36 IT group, and ⑦ BL 21 IT group, with 7 rats in each group. Rat gastric ulcer model was established using intra gastric administration of glacial acetic acid. Gastric mucosal thickness,mucosal muscular defect width,superficial mucosal mucus index (MI),intramucosal MI ,Total MI,plasma 6 keto PGF1α ,serum NO and gastric tissue CGRP concentrations were used as the indexes. The EA treatment was conducted once daily at Xu period (7-9 o’clock in the evening), Chen period (8-10 o’clock in the morning) and irregular time (IT) with 6 days being a therapeutic course, two courses altogether. Results:After EA treatment,①the regenerated mucosal thickness values of the aforementioned 6 EA groups, particularly ST 36 Xu group and BL 21 Xu group, were all apparently higher than that of control group (P<0.05-0.01), while the mucosal muscle layer defect width values of different EA groups, particularly ST 36 Xu group and BL 21 Xu group, were strikingly lower than that of control group (P<0.05-0.01); ②the 3 MI of the 6 EA groups, particularly those of ST 36 Xu group were all significantly higher than those of control group (P<0.05-0.01); ③plasma 6 keto PGF1α contents of the 6 EA groups, particularly those of ST 36 Xu and BL 21 Xu groups, were all significantly higher than that of control group (P<0.05-0.01); ④serum NO and gastric tissue CGRP concentrations of the 6 EA groups, particularly those of ST 36 Xu and BL 21 Xu groups and CGRP concentration of ST 36 Chen group, were all significantly higher than those of control group (P<0.05-0.01);and ⑤there were positive correlation between superficial MI or total MI and NO level (r=0.858, 0.987, P<0.05,and 0.01),and between the superficial mucus index and CGRP concentration (r=0.9051, t=4.68, P<0.01), suggesting that the increase of the secretion function of the regenerated mucosal mucus is related to acupuncture induced increase of release of both NO and CGRP.Conclusion:The therapeutic effect of EA of ST 36 and BL 21 in Xu period is better in the treatment of gastric ulcer,and that of EA of ST 36 is the best.

Midgut immune responses induced by bacterial infection in the silkworm, Bombyx mori

Insect gut epithelial cells produce reactive oxygen species （ROS） and antimicrobial peptides （AMPs） to protect hosts from pathogenic microorganisms. In this study, we evaluate the pathogenicity of Pseudomonas aeruginosa and Bacillus bombysepticus in the silkworm, Bombyx mori. Survival curves show that B. bombysepticus is deadly when larval silkworms are infected orally. Bacterial infection caused intestinal hydrogen peroxide （H202） and nitric oxide （NO） levels to increase significantly by 8 and 16 h post-infection （hpi）, respectively. Real-time quantitative polymerase chain reaction （qPCR） analysis shows that the transcription levels of dual oxidase （Duox） and catalase （CAT） are highly up-regulated by P. aeruginosa infection at 8 hpi. P. aeruginosa infection induced nitric oxide synthase 2 （NOS2） expression at 16 hpi, which contributes to the generation of NO. mRNA levels of AMP genes, specifically Glovorin 2 and Glovorin 3, which obviously increase during the eady infection stage. These results indicate that invading bacteria ele.vate intestinal ROS and NO levels and induce AMP gene transcription, which contributes to intestinal immune defense.