Changes of L-arginine,NOS/NO pathway in adventitia of rats with sepsis

AIM: In this study, we aimed to explore the alteration and pathophysiological significance of the L-arginine (L-Arg)/NOS/NO pathway in the adventitia of rats with sepsis. METHODS: Sepsis was induced by cecal ligation and puncture (CLP). Rat cardiac function was determined. NO generation, NOS activity and L-Arg transport were measured. The iNOS mRNA levels was determined by using RT-PCR. RESULTS: Cecal ligation and puncture induced severe sepsis with severe low glucose, high lacticemia and cardiac function inhibition. The iNOS activity was increased by 2.8-fold compared with controls (P<0.01) and the iNOS mRNA level was elevated-6-fold (P<0.01). The NO level in plasma and incubation media (incubation for 40 min) in the sepsis group was increased by 144% and 273% (both P<0.01), respectively. CONCLUSION: The results demonstrated that the L-Arg,NOS/NO pathway was activated in vascular adventitia of rats with sepsis shock. The aortic adventitia L-Arg/NOS/NO pathway might play an important role in the pathogenesis of sepsis and septic shock.     

Behavior changes of learning and memory related to the levels of NO and nNOS in brain of rats with acute alcoholism

AIM: In order to investigate the molecular mechanism of alcoholism acting on learning and memory, the dysfunction of learning and memory function was observed and the content of nitric oxide (NO) and neuronal nitric oxide synthase (nNOS) were determined in rats with acute alcoholism.METHODS: The mature male Sprague-Dawley rats were randomly divided into two groups. The experimental group animals were intraperitoneally administered with ethanol. The control group animals were injected with saline in the same way. The tests of learning and memory were performed at Y-maze after 6 h. Then brains were removed and the content of NO in brain tissue and nNOS expression in hippocampus CA1, corpus striatum were determined, respectively.RESULTS: (1) The training times to reach qualifying standards of Y-maze in experimental group (34.33±13.04) were higher than those in control group (27.50±8.79, P<0.05). (2) The content of NO in experimental group (23.09±9.60) in hippocampus CA1 was significantly increased (P<0.01) compared with that in control group (8.46±5.67). The content of NO in experimental group (19.46±8.25) in corpus striatum was also higher than that in control group (8.22±4.46, P<0.01). (3) The levels of nNOS expression in experimental group (34.33±13.04) in hippocampus CA1 increased significantly (P<0.05) compared with that in control group (27.50±8.79). nNOS positive neurons in experimental group (18.22±7.47) in corpus striatum were also higher than those in control group (10.15±4.24, P<0.05).CONCLUSION: These findings suggest that the mechanism of ethanol neurotoxicity may be partly involved in the signal pathway of NOS and NO in the brain.     

Influence of transection of the cervical sympathetic trunk on content of NO and expression of NOS in placenta of rats with pregnancy-induced hypertension syndrome

AIM:To observe the influence of transection of the cervical sympathetic track (TCST) on the content of NO and the expression of eNOS mRNA and iNOS mRNA in placenta of the rats with pregnancy-induced hypertension syndrome (PIH).METHODS: Pregnant Wistar rats were randomly divided into 5 groups: control group (C): saline was injected subcutaneously from 14th day to 20th day of gestation;PIH group 1 (H1) and group 2 (H2): L-NAME was respectively injected with 125 mg/kg and 62.5 mg/kg,respectively,then the other procedures were the same as group C;Operation group (O): TCST was operated on 14th day of the gestation,then the other procedures were the same as group H1;sham operation group (S): the cervical sympathetic trunk was only separated and exposed on 14th day of the gestation,then the other procedures were the same as group H1.RESULTS: (1) Except the base value of the BP and protein in urine of the pregnant rats,all the parameters observed in group H1 and H2 were higher than those in group C significantly (P<0.01),and in group H2 were lower than those in group B1 markedly (P<0.01).(2) In comparison with those in group C,the size and body weigh of fetus in group H1,H2 decreased markedly (P<0.01).The above indexes in group H1 were lower than those in group H2 markedly (P<0.01,P<0.05).The changes of the rate of embryo absorption and fetal death,and deformity rate of the fetal rats were contrary to the above indexes.(3) The content of NO and the expression of eNOS mRNA and iNOS mRNA in placenta in group H1 and H2 were lower than those in group C markedly (P<0.01).Those in group H1 were lower than those in group H2 obviously (P<0.01,P<0.05).Those in group O were higher than those in group H1 markedly (P<0.01).CONCLUSION: TCST protects pregnant rats against PIH,and it was related to the mRNA expression of eNOS and iNOS and the content of NO in placenta tissue.     

Expression of nitric oxide synthase and its clinical significance in hepatic cellular carcinoma

AIM: To investigate the expression of nitric oxide synthase (NOS) and its clinical significance in hepatic cellular carcinoma (HCC). METHODS: The NOS1, NOS2 and NOS3 of 51 cases of HCC and 46 cases of liver tissue beside carcinoma (LTBC) were detected by immunohistochemistry. RESULTS: The expressive rates of NOS1, NOS2 and NOS3 in LTBC were significantly higher than those in HCC (P<0.01). The expressive rates of NOS1 in the recurrent group was significantly higher than that in the non-recurrent group (P<0.01). The expressive rate of NOS2 in the group without carcinoma embolus was significantly higher than that in the group with carcinoma embolus (P<0.05). The expressive rate of NOS3 in the recurrent group was significantly higher than that in the non-recurrent group (P<0.01). CONCLUSION: The expression of NOS1, NOS2 and NOS3 are closely related with the biological behaviors of HCC.     

Effect of selenium compounds on ROS and NO production and NOS activity in human umbilical cord mesenchymal stem cells

AIM: To investigate the effects of selenium (Se) compounds on the generation of nitric oxide (NO) and reactive oxygen species (ROS), and the activity of nitric oxide synthase (NOS) in umbilical cord mesenchymal stem cells (MSCs). METHODS: MSCs were cultured in the medium of DMEM/F12 containing 10% FBS and exposed to the compounds of selenium , selenocysteine (Se-Cys) or nano-selenium (Nano-Se) at concentrations of 0.1 μmol/L to 0.5 μmol/L. The concentration of NO and the activity of NOS in treated MSCs were detected by the method of nitrate reductase assay. The fluorescent intensity of ROS was determined by DCFH-DA probe. RESULTS: The production of NO was (18.13±6.80) μmol/L in the control MSCs,(20.93±5.68) μmol/L in the MSCs treated with Se(Ⅳ) at concentration of 0.1 μmol/L and (16.73±5.03) μmol/L in the MSCs treated with Se(Ⅳ) at concentration of 0.5 μmol/L for 24 h. The production of NO was (17.20±9.11) μmol/L (P<0.05) in the MSCs treated with Se(IV) at concentration of 0.1 μmol/L and (9.98±4.35) μmol/L (P<0.01) in the MSCs treated with Se(IV) at concentration of 0.5 μmol/L for 48 h, which was significantly lower than that in the control MSCs . No inhibitory effect of Nano-Se and Se-Cys on the production of NO in MSCs was observed. Compared with the control MSCs, Se(Ⅳ) at concentrations of 0.1 μmol/L and 0.5 μmol/L significantly inhibited the generation of ROS and the activity of NOS in MSCs at 24 h and 48 h. CONCLUSION: Se(Ⅳ) inhibits NO/ROS production and NOS activity in a dose-dependent manner in MSCs.     

Comparison of iNOS mRNA expression in colorectal carcinoma cell strains with different proliferation protentials

AIM: To evaluate the expression of iNOS mRNA in different invasion ability colon carcinoma cell strains. METHODS: MTT was used to detect the growth and reproduction of colon cancer cell strain CW-2 and LS174T. RT-PCR and Northern blot were used to detect expression of iNOS mRNA in colon cancer. RESULTS: MTT growth curve displayed that colon cancer cell strain LS174T grew and reproduced faster than cell strain CW-2. RT-PCR showed that iNOS mRNA expressed strongly in CW-2 cell strain, while iNOS mRNA expressed weakly in LS174T cell strain. Northern blot detected that iNOS mRNA expressed obviously in CW-2 cell strain, but cell strain LS174T have no obvious iNOS mRNA expression. All-trans retinoic acid (ATRA) had no obvious effect on iNOS mRNA expression in CW-2 cell strain of colon cancer. CONCLUSIONS: ATRA has no obvious effect on iNOS mRNA expression. iNOS has a dual effect on tumor growth. In low-metastatic colon carcinoma CW-2, iNOS may exert it's anti-tumor influence by cytotoxicity or inducing cell apoptosis. In high-metastatic colon cancer LS174T, iNOS produced low concentration of NO, which may be an important signal-transduction molecule for increasing blood supply and angiogenesis, which improve the growth, invasion and metastasis of tumor.     

Effect of inactivated SARS coronavirus vaccine on mouse organs

AIM: To study the pathological change in mouse organs immunitied by inactivated SARS-CoV vaccine. METHODS: Inactivated SARS-CoV vaccine was injected into BALB/c and C57BL/6 mice. Anti-SARS antibody was analyzed by ELISA. After 8 weeks, the immunitied mice were killed and those organs were analyzed by pathological methods. RESULTS: Anti-SARS antibody in mice was positive after 8 days. Only minimal injury was observed in a few lungs and livers, but the other organs were not. CONCLUSIONS: Inactivated SARS-CoV vaccine induced mice to create antibody, whereas they did not cause severe injury. This result will be valuable for vaccine into clinical research.     

Septic shock down-regulates L -arginine /NOS /NO pathway of platelet and aortic intima in rats

AIM: To investigate alteration and cross link of the aortic and platelet endogenous L -arginine/NOS/NO pathway induced by septic shock.METHODS: The septic shock model was made in rats by caecal ligation and puncture. NO^-₂/NO^-₃ production released from aortic and platelet was measured with Greiss assay. NOS activity and L-arginine transport activity were detected by isotope tracer method. RESULTS: Both in early and late stage of septic shock, NO^-₂/NO^-₃ production, NOS activity, and the L-arginine transport from the aorta intima and platelets were obviously decreased, while those of the aorta media and adventitia were obviously increased (P<0.01), but high-affinity L-arginine transport activity from the aorta intima and platelets was increased in early stage of septic shock (P>0.05 and P<0.05), as compared with the sham group, respectively. The inhibitory effects of NO^-₂/NO^-₃, NOS activity and the L-arginine transport showed a positive correlation between platelet and aortic intima (P<0.01). CONCLUSION: Septic shock down-regulates endogenous L-arginine/NOS/NO pathway in aortic intima and platelet, up-regulates L-arginine/NOS/NO pathway of aortic media and adventitia. Detection of the alteration of endogenous L-arginine/NOS/NO pathway in platelet might act as an indirect method to assess the endothelial dysfunction involving the pathogensis of septic shock.     

Nitric oxide production,NOS activity and expression in pulmonary arterioles of rats with chronic hypoxic hepercapnic pulmonary hypertension

AIM: To clarify the role of nitric oxide (NO) system in development of chronic hypoxic hypercapnic pulmonary hepertension. METHODS: Male Sprague-Dawley rats were randomly divided into control group and hypoxic hypercapnic group. NO content of plasma was determined, constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) were examined using the technique of immunohistochemistry, expression of cNOS mRNA and iNOS mRNA of arteriole were detected by in situ hybridization. RESULTS: Plasma NO concentration, cNOS activity and cNOS mRNA expression in arteriole of chronic hypoxic hypecapnic group were significantly lower than that of control group (P<0.01); activity of iNOS and expression of iNOS mRNA in arteriole showed significantly higher compared with control. CONCLUSION: The disturbance of NO production and NOS expression in arteriole are involved in hypoxic hypercapnic pulmonary hepertension.     

Dynamic changes of the concentration of nitric oxide in ischemic myocardium and its mechanism

AIM: The study was undertaken to explore the dynamic changes of the concentration of nitric oxide(NO) in ischemic myocardium and its mechanism.METHODS: In vivo myocardial ischemia of mice and in vitro perfused isolated heart of rat were used in the experiment. The effects of severity and time of ischemia on NO production, NOS activity and mRNA were examined, respectively. RESULTS: There was a considerable difference (P<0.01) in the concentration of NO between ischemia group [(9.12±1.40) μmol/L] and control group [(20.16±1.67) μmol/L] after Pit(30 U/kg) administration, and the concentration of NO of ischemic group significantly decreased [(9.17±1.33) μmol/L] compared with control group [(19.90±1.95) μmol/L] after 30 minutes of ischemia. Also, the concentration of NO after Pit(20 U/L) administration in K-H and 15 min of ischemia was (15.41±2.00) μmol/L and (15.09±2.00) μmol/L respectively in vitro, significantly lower than control group [(23.83±2.33) μmol/L and (23.63±2.52) μmol/L]. In addition, compared with control group, the number of NOS positive cells, NOS activity as well as mRNA expression in atrial muscle and ventricular muscle of ischemic group were markedly reduced, respectively. CONCLUSION: Myocardial ischemia could reduced the NO level in myocardium, down-regulation of NOS mRNA could be the possible mechanism.     

Renoprotective effects of sesamin on renal hypertensive and hyperlipidemic rats

AIM: To investigate the effects of sesamin on progression of renal injury in renal hypertensive and hyperlipidemic rats (RHHR). METHODS: RHHR was induced by 2K1C and high lipid baitvessel. After 7 weeks of intragastric administration with sesamin, the contents of serum creatinine (Scr), blood urea nitrogen (BUN), 24 h urinary protein excretion (UPE) were measured. In addition, the activity of total antioxidative capacity (T-AOC), superoxide dismutase (SOD), the concentrations of malondialdehyde (MDA), hydrogen peroxide (H2O2), and the nitric oxide synthase (NOS) and nitric oxide (NO) levels in renal homogenate were measured. RESULTS: Compared with the model group, seasamin (in 100 mg·kg-1 and 33 mg·kg-1 groups) evidently decreased the contents of Scr, BUN, UP and the concentration of MDA, iNOS, H2O2 in renal tissure. It also improved the levels of NO, cNOS and activity of SOD, T-AOC in renal tissure. CONCLUSION: Sesamin ameliorates hypertensive and hyperlipidemic-induced renal injury, probably by enhancing antioxidative activity, scavenging hydroxyl radical and restraining iNOS level.     

Alterations of nitric oxide synthase in cardiac sarcoplasmic reticulum from rats with myocardial calcification

AIM: To study alterations of nitric oxide synthase (NOS) in cardiac sarcoplasmic reticulum from rats with myocardial calcification, and to explore the mechanism of inhibition of SR function in the rats with myocardial calcification. METHODS: Compared with control, myocardial calcium content in the 6 weeks increased by 408%（Ｐ＜0.01）, the NO production, NOS activity and NOS protein expression in the SR with myocardial calcification increased versus control（Ｐ＜0.01）.Myocardial calcium content was not alterations significantly, but the NOS/NO pathway in the SR was up-regulated slightly in the 2 weeks. RESULTS: Compared with control, myocardial calcium content in the 6 weeks increased by 408%(P＜0.01), the NO production, NOS activity and NOS protein expression in the SR with myocardial calcification increased versus control(P＜0.01).Myocardial calcium content was not alterations significantly, but the NOS/NO pathway in the SR was up-regulated slightly in the 2 weeks. CONCLUSION: The up-regulated NOS/NO system in the SR with myocardial calcification is the important mechanism of function inhibition of the SR.     

Changes in L-arginine/nitric oxide pathway of the aorta in septic shock rats

AIM:To observe the change of nitric oxide (NO) generation system in the vascular adventitia, media and intima in septic shock rats.METHODS:The septic shock model was made in rats by caecal ligation and puncture. The intima, media and adventitia of the rat aorta were separated. NO production (NO₂^-), nitric oxide synthase(NOS) activity and L-arginine (L-Arg) transport were measured, separately. Inducible NOS (iNOS) distribution was detected by immunohistochemistry.RESULTS:Both in early and late stage of septic shock, NO₂^- from the intima was decreased by 66.1% and 78.9%(P<0.01), while NO₂^- from the media was increased by 1.1 and 2.2 folds(P＜0.01), and the adventitia 9.6 and 18.6-fold (P＜0.01), as compared with the sham group, respectively. The changes of NOS activity and the L-arginine transport in the intima, the media layer and the adventitia of the aorta in the septic shock rat paralleled with that of NO₂^- in these tissues. The results of iNOS immunohistochemistry showed that there were obviously positive staining in the media layer and adventitia, especially the adventitia of the rat aortas in septic shock, as compared with that in the sham control.CONCLUSIONS:During septic shock, NO production in the aortic intima was progressively suppressed. However, it was progressively increased in the aortic medial layer and adventitia, especially the adventitia with shock processes. These changes result from different changes of L-arginine transport, NOS activity and its expression in three layers of the aorta from the septic shock rat.     

Changes and clinical significance of serum protein factors in patients with polycystic ovary syndrome

AIM:To study the changes and clinical significance of serum protein factors in the patients with polycystic ovary syndrome (PCOS). METHODS:The relative expression levels of 174 ser protein factors in 5 PCOS patients and 5 control women were assayed simultaneously by Antibody Protein Array 2000,in which 2 factors were chosen to test and reconfirm the results by ELISA in 30 cases of PCOS patients and 30 cases of controls. RESULTS:Among 174 serum protein factors, the factors that elevated in PCOS patients were angiogenin, EGF, IGFBP-1, IGFBP-4, IL-7, MIP-1-delta, PARC, PDGF-BB, Acrp30, EGFR, ICAM-1, sTNF-RI, TIMP-2, TRAIL-R3, E-selectin, IL-1RII, IL-5Ra, LAP, L-selectin, M-CSFR, PDGF-AA, prolactin and VEGFR2, while the factors that decreased in PCOS patients were GRO, IL-8 and Siglec-5. Nine factors were increased 3 times more than the controls(IL-1R-II, prolactin, IL-7, IGFBP-1, IL-5Ra, IGFBP-4, VEGFR2, ICAM-1 and MIP-1-delta). PDGF-BB and Acrp30 were tested by ELISA in 60 samples and there were significant differences between the 2 groups. CONCLUSION: The changes of the protein factors in serum might play an important role in the pathogenesis of PCOS.     

Role of renal cortex endothelin and NO in the development of proteinuria

AIM: To test the hypothesis that locally produced renal endothelin(ET) and nitric oxide(NO) play more important role in initiating proteinuria than circulating ET and NO. METHODS: (1) Rat nephrotic syndrome model was made by single injection of adriamycin, and the urinary protein excretion per 24 hours for every two days was measured. (2) Rat plasma and renal cortex were collected respectively 4 days, 8 days, 32 days and 56 days after the injection, and renal cortex homogenate was further prepared; ET of both plasma and renal cortex homogenate were determined by radioimmunoassay; NO of both plasma and renal homogenate were measured by the method of Griess. (3) The correlation between urinary protein and ET or NO concentration was analyzed respectively. RESULTS: (1) The urinary protein excretion of normal rat was 4-7 mg/d, that in nephrotic rat at the 4 time points was 5, 10, 241 and 201 mg/d, there was a significant increase of that at day 8, peaked at day 32, and less decrease at day 56. (2) The plasma ET in nephrotic rats of the 4 time points was 134, 150, 538 and 445 μg/L, respectively, which of day 8, day 32 and day 56 shown significant higher than that of normal control (126-129 μg/L). (3) The ET in renal cortex homogenate of nephrotic rat of the 4 time points was 364.6, 652.3, 1 526.8, 1 393.6 pg/g, all of that was much more higher than that of normal rat . (4) The plasma NO in nephrotic rat of the 4 time points was 40, 36, 8 and 11(μmol/L), there was considerable difference through day 8 to day 56 than control (42-46μmol/L, P＜0.05). (5) The NO in renal cortex homogenate of nephrotic rat was 80, 69, 8, 25 μmol/L that of normal rat was (114-124) μmol/L, there was significant difference between nephrotic rat and control from day 4 through day 56( P＜0.05). (6) The correlation coefficient of plasma ET and NO with separately urinary protein excretion shown statistic significance on only day 8 and day 56, while all of that of ET and NO in renal homogenate closely related with urinary protein from day 4 through to day 56. CONCLUSION: The ET and NO produced locally in renal play more important role in the development of proteinuria.     

Liver protection by Sini decoction in hemorrhagic shock and its mechanism relating to oxygen free radical and nitric oxide

AIM:The work was designed to explore protective effects of a traditional Chinese medicine-sini decoction (SD) on liver in hemorrhagic shock and its mechanism relating to oxygen free radical and nitric oxide.METHODS:Anesthetized Wistar rats were subjected to a hemorrhagic shock protocol for 60 min followed by intravenous injection with normal sodium chloride solution or SD solution. Superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) in liver were examined. The inducible nitric oxide synthase (iNOS) was determined immunohistochemically. RT-polymerase chain reaction (RT-PCR)was used to assay the mRNA, which were corresponding to eNOS (endothelial nitric oxide synthase) and iNOS.RESULTS:The activity of SOD decreased, while the concentration of MDA increased in liver during hemorrhagic shock. SD enhanced SOD activity and inhibited a increase in MDA level in liver (P＜0.01). The NO concentrations in liver in SD group increased at three hours after resuscitation (P<0.01). In addition, it was found that the expression of iNOS was upregulated in sodium chloride-treated group, while SD upregulated the expression of eNOS.CONCLUSION:SD reduces the liver injury caused by oxygen free radicals during hemorrhagic shock. The increasing NO concentration by SD is through upregulation of endothelial NOS expression.     

Protective effect of panaxadiols against brain injury induced by LPS through inhibiting NOS activity and p38 expression

AIM: To explore the protective effect of panaxadiols (PDS) on brain injury induced by endotoxin and its mechanism. METHODS: Rats were divided into control,LPS,LPS+dexamethasone (DEX) and LPS+PDS group, respectively. NOS activity, NO content and phosphorylated p38 expression in brain cortex were assayed 4 h after intravenous injection of LPS. RESULTS: NOS activity, NO content and phosphorylated p38 expression in brain cortex in LPS group were obviously higher than those in LPS group. NOS activity, NO content and phosphorylated p38 expression in brain cortex in LPS+DEX and LPS +PDS groups were obviously lower than those in LPS group. CONCLUSION: The protective effects of PDS against brain injury induced endotoxin may be related to decreasing NOS activity, NO content in the brain tissue, and this process is involved in p38MAPKs signal transduction.     

Analysis of pathogenic biology of SARS-associated coronavirus and its implication

Severe acute respiratory syndrome (SARS) is the first new epidemic of the twenty-first century. A novel coronavirus (SARS-CoV) has been identified as the causative agent of SARS. The genome of SARS-CoV has 29 727 nucleatides in length. The genome organization, with 11 open reading frames, is similar to that of coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the known coronaviruses, indicating neither a mutant nor recombinant of wel-characterized coronaviruses. It is a complete new coronavirus from nonhuman host. Pathological studies show that severe immune response, associated to cytokine dysregulation, may be related to the lung damage of fatal SRAS. Recombination of genomes of wild-type strains with vaccine coronavirus is a potential risk associated with the application of living attenuated coronavirus vaccines. The proteinases, controlling the activities of the SARS-CoV replication, and spike protein, involved in viral entry and pathogenesis, represent at ractive targets of anti-SARS drug development. Comparative full-length genome sequence analysis of 14 SARS coronavirus isolates suggests a remarkable genetic conservation of the virus. Anti-SARS vaccine and drug development wil benefit from this genet ic conservation.SARS-CoV is not likely to change rapidly and thus may not readily mutate to a benign infection. The progress in anti-SARS research has been impressive. However, one of the most effective tools in the control of the SARS is quickly tracing and isolating the contacts of stricken patients before they spread the virus further.     

Effects of PPARβ and NO on high glucose and insulin-induced cardiomyocyte hypertrophy

AIM: To investigate the role of peroxisome proliferator-activated receptor β(PPARβ)-nitric oxide(NO) signal pathway in cardiomyocyte hypertrophy induced by high glucose(25.5 mmol/L) and insulin(0.1 μmol/L)(HGI). METHODS: The cardiomyocyte hypertrophy was characterized in rat primary cardiomyocytes by measuring the cell surface area, protein content, and the mRNA expression of atrial natriuretic factor(ANF). The mRNA and protein expression were measured by real-time PCR and Western blotting, respectively. The activity of NO synthase(NOS) and NO content were measured by a reagent kit through ultraviolet spectroscopy. RESULTS: HGI induced profound change of hypertrophic morphology, and significantly increased the cell surface area, protein content and mRNA expression of ANF(P<0.01), but decreased the expression of PPARβ at mRNA and protein levels(P<0.05). At the same time, the expression of inducible NOS(iNOS) was obviously elevated(P<0.01), which occurred in parallel with the rising NOS activity and NO concentration(P<0.01). GW0742(1 μmol/L), a selective PPARβ agonist, inhibited the cardiomyocyte hypertrophy induced by HGI(P<0.01), and up-regulated the expression of PPARβ at both mRNA and protein levels. Meanwhile, GW0742 also inhibited the increases in iNOS expression, NOS activity, and NO content induced by HGI, which were abolished by GSK0660(1 μmol/L), a selective PPARβ antagonist(P<0.01). CONCLUSION: PPARβ down-regulation and the following iNOS-NO activation are involved in the cardiomyocyte hypertrophy induced by HGI.     

Effects of folic acid on antioxidant enzyme,nitric oxide synthase and nitric oxide in ovariectomized rats

AIM: To observe the effects of folic acid (FA) on antioxidant enzyme, nitric oxide synthase (NOS) and nitric oxide (NO) in ovariectomized (OVX) rats.METHODS: Forty three-month-old female SD rats were randomly divided into 5 groups: sham group, OVX group, diethylstilbestrol group (0.03 mg·kg^-1·d^-1), low-dose FA group (5 mg·kg^-1·d^-1) and high-dose FA group (20 mg·kg^-1·d^-1). Gastric gavage started 1 week after operation and lasted for 10 weeks. The rats in sham group and OVX group were given distilled water instead of FA as controls. At the end of the 10th week, the L₅ vertebra and right femur were removed for determination of bone mineral density (BMD). The bone homogenates were made using the L₃ and L₄ vertebrae. The levels of the total antioxidant capacity (TAC), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), NOS and NO were detected in plasma and bone homogenates.RESULTS: Compared with sham group, the BMD levels in L₅ vertebra and right femur and the levels of GSH-Px and NO in the plasma were all decreased. The levels of TAC, GSH-Px, NOS and NO in the bone homogenates were also decreased, while the MDA concentration was increased in OVX group (all P < 0.01). Compared with OVX group, the levels of TAC, GSH-Px, NOS, NO and BMD of the L₅ vertebra and right femur were all increased, while the MDA concentration was decreased in high-dose FA group (all P < 0.01). CONCLUSION: In female SD rats, ovariectomy leads to a significant reduction of antioxidant enzyme, NOS and NO levels. Oxidative stress is possibly involved in the development of osteoporosis. Protection against osteoporosis by high-dose FA may be linked to improvement of antioxidant enzyme activity, the levels of NOS and NO as well as a reduction of oxidative stress in ovariectomized rats.