BACKGROUNDPreeclampsia (PE) is a multifactorial pregnancy complication. Maternal underlying condition and adverse factors both influence the pathogenesis of PE. Abnormal lipid metabolism as a maternal underlying disease may participate in the occurrence and development of PE. This study aimed to observe the effects of adverse factors on PE-like symptoms of pregnant mice with genetic abnormal lipid metabolism.

METHODSApolipoprotein C-III (ApoC3) transgenic mice with abnormal lipid metabolism were subcutaneously injected with L-arginine methyl ester (L-NAME) or normal saline (NS) daily starting at Day 7 or 16 of pregnancy (ApoC3+L-NA and ApoC3+NS groups), and wild-type (WT) mice served as a control (WT+L-NA and WT+NS groups). All mice were subdivided into early and late subgroups by injection time. The mean arterial pressure (MAP) and urinary protein were measured. Pregnancy outcomes, including fetal weight, placental weight, live birth rate, and fetal absorption rate, were analyzed. Pathologic changes in the placenta were observed by hematoxylin-eosin staining. One-way analysis of variance, t-test, and χ(2) test were used for statistical analysis.

RESULTSMAP significantly increased for ApoC3+NS groups compared with WT+NS groups (P < 0.05), without significant difference in urine protein. Following L-NAME injection, MAP and urinary protein significantly increased for ApoC3+L-NA and WT+L-NA compared with the corresponding NS groups (P < 0.05), and the increase for ApoC3+L-NA was more obvious. Urinary protein levels in early ApoC3+L-NA and WT+L-NA significantly increased compared with the corresponding late groups (P < 0.05). Fetal absorption rate significantly increased and fetal and placental weights significantly decreased in early ApoC3+L-NA and WT+L-NA compared with the corresponding NS groups (P < 0.05), without significant difference in late ApoC3+L-NA and WT+L-NA groups. Fetal weight in early ApoC3+L-NA was significantly lower than in early WT+L-NA group (P < 0.05). Morphologic examination of placentas from early ApoC3+L-NA and WT+L-NA groups showed varying degrees of fibrinoid necrosis.

CONCLUSIONSApoC3 transgenic mice with abnormal lipid metabolism showed gestational hypertension. Adverse factors and early effect time could aggravate the PE-like symptoms for ApoC3 transgenic mice.

Animals ; Apolipoprotein C-III ; genetics ; metabolism ; Female ; Lipid Metabolism ; drug effects ; genetics ; Male ; Mice ; Mice, Transgenic ; NG-Nitroarginine Methyl Ester ; pharmacology ; Pre-Eclampsia ; genetics ; metabolism ; Pregnancy

OBJECTIVETo explore if the hypoxia/reoxygenation-induced increased activity and expression of PTP-1B in neonatal rat cardiomyocytes are mediated by nitric oxide (NO).

METHODSNeonatal rat cardiomyocytes were isolated and randomly divided into 4 groups: normal group (N group); hypoxia/reoxygenation group (H/R group); N(omega)-nitro-l-arginine methylester treated group (L-NAME group); hypoxia/reoxygenation plus L-NAME group (L-NA + H/R group). PTP-1B activity in cardiomyocytes was determined spectrophotometrically at 405 nm, PTP-1B expression in cardiomyocytes was detected by Western blot.NO and LDH concentrations in cell medium were also assayed.

RESULTSPTP-1B activity and expression in cardiomyocytes was significantly higher in the H/R group as compared to the N group and this increase could be blocked by cotreatment with L-NAME. As compared to H/R group, nitric oxide and LDH concentrations in cell medium were significantly decreased in the L-NA + H/R group (NO concentration: H/R group, 368% +/- 13% and L-NA + H/R group, 61% +/- 7%, P < 0.005; LDH concentration: H/R group, 41.2 +/- 6.7 and L-NA + H/R group, 23.6 +/- 4.8, P < 0.05).

CONCLUSIONSThis study showed that pretreatment with L-NAME, a non-selective inhibitor of NOS, prevented the hypoxia/reoxygenation-induced increase in PTP-1B activity and expression in cardiomyocytes, suggesting PTP-1B activation during hypoxia/reoxygenation was mediated by nitric oxide.

Animals ; Cell Hypoxia ; Cells, Cultured ; Myocytes, Cardiac ; cytology ; metabolism ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; metabolism ; Rats

The role of nitric oxide during neonatal sepsis is complex. We tested the hypothesis that nonselective inhibition of nitric oxide synthase with N(w) -nitro-L-arginine methyl ester (L-NAME) is detrimental during the early phase of experimental sepsis in the newborn piglet. Newborn piglets were divided into four groups: 6 in the control group, 6 in the L-NAME control group, 12 in the sepsis group (SG), and 11 in the sepsis with L-NAME group (NS). Sepsis was induced by intravenous injection of 10(8) colony forming units of Escherichia coli. L-NAME 10 mg/kg was given intravenously 60 min before the induction of sepsis. The survival rate of piglets after 4 hr was 27% in NS, while it was 100% in other groups. Systemic hypotension, observed in both SG and NS, were more profound in NS. Leukopenia was observed in both SG and NS. Thrombocytopenia, prolongation of prothrombin time and activated partial thromboplastin time, and increase in thrombin-antithrombin complexes were observed only in NS. Decreased PaO2 /FiO2 ratio, arterial pH and base excess, and increased blood lactate levels observed in both SG and NS, but were more profound in NS. These findings suggest that nonselective inhibition of nitric oxide synthase with L-NAME is detrimental during the early phase of experimental neonatal sepsis.
Animals ; Animals, Newborn ; Enzyme Inhibitors/pharmacology ; Escherichia coli/*metabolism ; NG-Nitroarginine Methyl Ester/*pharmacology ; Sepsis/*drug therapy ; Support, Non-U.S. Gov't ; Swine ; Time Factors

The effect of systemic administration of nonspecific nitric oxide synthase inhibitor (N(omega)-nitro-L-arginine methyl ester, L-NAME) on morphine analgesia tolerance was observed by using the thermal tail-flick method, and the roles of NO and NMDA receptors in morphine analgesia tolerance were evaluated on the basis of the expressions of nNOS mRNA, NR1A mRNA and NR2A mRNA in spinal cord and midbrain. Thirty-six healthy adult Sprague-Dawley rats were randomly divided into six groups (6 rats per group). Group 1, control group, received a subcutaneous (s.c.) injection of normal saline (1 ml); Groups 2, 3, 4, 5 and 6, the treatment groups received s.c. injection of L-NAME 10 mg/kg, L-NAME 20 mg/kg, morphine 10 mg/kg, L-NAME 10 mg/kg + morphine 10 mg/kg, and L-NAME 20 mg/kg + morphine 10 mg/kg, respectively. All rats received s.c. injections twice per day (8:00 and 17:00). The tail-flick latency (TFL) was measured in each rat before the injection as a baseline value, and then TFL at 50 min after the 1st injection every day as the measuring values. The animals (except for groups 2 and 5) were decapitated at 80 min after the last injection on the 8th day. The spinal segments and midbrain were removed for analysis of nNOS mRNA, NR1A mRNA and NR2A mRNA expressions by the RT-PCR method. The results showed that TFL remained unchangeable in group 2 compared with baseline value during the 7-day observation, while increased significantly on the 7th day in group 3. In group 4, TFL was longest on the 1st day, then decreased gradually from the 2nd day to the 6th day, and restored to the baseline value on the 6th day. In group 5, TFL showed a decreasing tendency during the 7-day observation, but was still significantly longer than the baseline value on the 7th day. The changes of TFL obtained in group 6 were similar to those in group 5. The results of RT-PCR showed that as compared with group 1, nNOS mRNA expressions in spinal cord and midbrain were significantly down-regulated in group 3, but the expressions of the NR1A mRNA and NR2A mRNA in both groups were similar, while the nNOS mRNA, NR(1A) mRNA and NR(2A) mRNA expressions were all significantly up-regulated in group 4. As compared with group 4, the expressions of nNOS mRNA, NR(1A) mRNA and NR(2A) mRNA were significantly inhibited in group 6. These results suggest that the expressions of nNOS and NMDA receptors in spinal cord and midbrain were significantly up-regulated in the rats with morphine analgesia tolerance. Chronic co-administration of L-NAME could effectively inhibit the morphine-induced overexpressions of nNOS and NMDA receptors, and postpone the development of morphine analgesia tolerance. Based on the results of this study, it is concluded that NO/NMDA receptor in spinal cord and midbrain is closely related to the development of morphine analgesia tolerance.
Analgesia ; Animals ; Drug Tolerance ; Mesencephalon ; metabolism ; Morphine ; pharmacology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide Synthase ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Spinal Cord ; metabolism ; Up-Regulation

Hypoxic pulmonary vasoconstriction (HPV), a unique response of pulmonary circulation, is critical to prevent hypoxemia under local hypoventilation. Hypoxic inhibition of K+ channel is known as an important O2-sensing mechanism in HPV. Carbon monoxide (CO) is suggested as a positive regulator of Ca2+-activated K+ channel (BK(Ca)), a stimulator of guanylate cyclase, and an O2-mimetic agent in heme moiety-dependent O2 sensing mechanisms. Here we compared the effects of CO on the HPV (Po2, 3%) in isolated pulmonary artery (HPV(PA)) and in blood-perfused/ventilated lungs (HPV(lung)) of rats. A pretreatment with CO (3%) abolished the HPV(PA) in a reversible manner. The inhibition of HPV(PA) was completely reversed by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. In contrast, the HPV(lung) was only partly decreased by CO. Moreover, the partial inhibition of HPV(lung) by CO was affected neither by the pretreatment with ODQ nor by NO synthase inhibitor (L-NAME). The CO-induced inhibitions of HPV(PA) and HPV(lung) were commonly unaffected by tetraethylammonium (TEA, 2 mM), a blocker of BK(Ca). As a whole, CO inhibits HPV(PA) via activating guanylate cyclase. The inconsistent effects of ODQ on HPV(PA) and HPV(lung) suggest that ODQ may lose its sGC inhibitory action when applied to the blood-containing perfusate.
Animals ; Anoxia/*physiopathology ; Carbon Monoxide/*pharmacology ; Guanylate Cyclase/antagonists & inhibitors/metabolism ; NG-Nitroarginine Methyl Ester/chemistry/pharmacology ; Nitric Oxide Synthase/antagonists & inhibitors/metabolism ; Oxadiazoles/chemistry/pharmacology ; Pulmonary Artery/*physiopathology ; Quinoxalines/chemistry/pharmacology ; Rats ; Tetraethylammonium/chemistry/pharmacology ; Vasoconstriction/*drug effects/physiology

An enhanced formation of nitric oxide(NO), due to the induction of inducible nitric oxide synthase(iNOS), has been implicated in the pathogenesis of shock and inflammation, but its role in acute pancreatitis still remains controversial. To clarify the role of NO in acute pancreatitis, the present experiment investigated the expression of iNOS and the effect of NOS inhibition on cerulein-induced pancreatitis in rats. Group I received intraperitoneal (ip) injection of normal saline. Group II received two ip injections of cerulein (20 microgram/kg). Group III received injections of N(G)-nitro-L-arginine methyl este(L-NAME) (30 mg/kg) with cerulein. Group IV received L-arginine(250 mg/kg) with cerulein and L-NAME. The expression of iNOS in the pancreas was examined by western blot analysis. The plasma concentration of NO metabolites was measured. The severity of pancreatitis was assessed by measuring serum amylase, pancreas water content and histopathological examination. Compared with controls, the cerulein group displayed significantly increased expression of iNOS and raised plasma NO metabolites. Treatment with L-NAME significantly decreased hyperamylasemia, plasma NO level, and the extent of pancreatic injury. Treatment with L-arginine reversed the effects of L-NAME. These findings suggest that an enhanced formation of NO by iNOS plays an important role in the development of acute pancreatitis, and inhibition of NO production has the beneficial effects in reducing pancreas injury.
Amylases/blood ; Animals ; Arginine/pharmacology ; Blotting, Western ; Caerulein/*pharmacology ; Enzyme Inhibitors/pharmacology ; Inflammation ; Male ; NG-Nitroarginine Methyl Ester/pharmacology ; Necrosis ; Nitric Oxide/metabolism/*physiology ; Nitric-Oxide Synthase/metabolism ; Pancreatitis/*chemically induced/*metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the effects of Xuezhikang and simvastatin on cerebral ischemia/reperfusion injury in rat, as well as the influences after intervention with L-NAME.

METHODRats were given orally with Xuezhikang and simvastatin or vehicle for 2 weeks, and then subjected to middle cerebral artery occlusion for 120 min using intraluminal filament model. L-NAME were injected into the lateral ventricles in half of the rats treated with Xuezhikang and simvastatin 45 min before the ischemia. The neurological deficits examinations were performed at 2, 24, 48 h after reperfusion. After the last examination the animals were sacrificed, the infarct volumes were determined by TTC staining, and MDA levels were also measured.

RESULTXuezhikang and simvastatin both significantly reduced the infarct volume and improved the functional recovery when compared to vehicle. Xuezhikang and simvastatin both significantly decreased the MDA accumulation after reperfusion. L-NAME partially inhibited the protective effect of Xuezhikang but nearly completely abolished the protective effect of simvastatin.

CONCLUSIONXuezhikang has protective effects on ischemic brain damage in rats, which the beneficial effects are partly due to the statins components. The other components in Xuezhikang may also account for the neuroprotective effects, which is worth further investigations.

Animals ; Brain ; pathology ; Brain Ischemia ; etiology ; metabolism ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Infarction, Middle Cerebral Artery ; complications ; Male ; Malondialdehyde ; metabolism ; NG-Nitroarginine Methyl Ester ; pharmacology ; Neuroprotective Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; etiology ; metabolism ; pathology ; Simvastatin ; pharmacology

The aim of the present study was to examine the functional changes that occur when a rabbit carotid artery is cultured in serum-free medium. In endothelium (EC)-intact arteries cultured under serum-free conditions, acetylcholine (ACh)-induced relaxation responses were partially, yet significantly, reduced when compared with freshly isolated arteries. After pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, application of ACh resulted in a significant contraction in organ cultured arteries. The amplitude of the ACh-induced contractions increased with the duration of culture. In EC-denuded arteries cultured under serum-free conditions, ACh induced responses similar to those in EC-intact arteries pretreated with L-NAME. Furthermore, ACh caused a significant increase in intracellular Ca2+ concentration ([Ca2+]i) in EC-denuded arteries cultured under serum-free condition for 7 days. There was little change in either [Ca2+]i or tension in freshly isolated carotid rings. There was no difference in sodium nitroprusside-induced relaxation responses between fresh and cultured arteries. These results suggest that prolonged culture of carotid arteries under serum-free conditions changes the functional properties of vascular reactivity in rabbit carotid arteries.
Time Factors ; Rabbits ; Organ Culture Techniques/*methods ; Nitroprusside/pharmacology ; NG-Nitroarginine Methyl Ester/metabolism/pharmacology ; *Muscle Contraction ; Models, Statistical ; Dose-Response Relationship, Drug ; Culture Media, Serum-Free/metabolism ; Carotid Arteries/*drug effects/metabolism/*pathology ; Calcium/metabolism ; Animals ; Acetylcholine/*pharmacology

The aim of the present study was to explore the effect of nitric oxide (NO) on iron-induced toxicity in rat hearts. Langendorff perfused rat heart and enzymatically isolated cardiomyocytes were used. It was shown that lipophilic Fe-HQ reduced the contractile amplitude, velocity and end-diastolic cell length in the cardiomyocyte, while the left ventricular developed pressure (LVDP), +/-dp/dt(max), heart rate and coronary flow showed biphasic alterations, which increased in the first 2 min and then was followed by a decline in isolated perfused rat heart; the contents of lactate dehydrogenase (LDH) and creatine kinase (CK) in the coronary effluent and the malondialdehyde (MDA) in the myocardium were increased. L-arginine (L-Arg), an NO precursor, reduced the contractile amplitude and end-diastolic cell length in the cardiomyocyte; but reversibly increased LVDP, +/-dp/dt(max), and coronary flow in isolated perfused rat heart. Pretreatment with L-Arg aggravated the Fe-HQ-induced decrease in contractile amplitude, velocity and end-diastolic cell length in the cardiomyocyte; LVDP, +/-dp/dt(max), heart rate and coronary flow were significantly reduced in the perfused heart, and the levels of LDH and CK increased in the coronary effluent. In contrast, the NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) blocked the Fe-HQ induced change in contractile amplitude, velocity and end-diastolic cell length in the cardio- myocyte; it inhibited the decrease in LVDP, LVEDP and +/-dp/dt(max), and reduced the LDH and CK. Removing endothelial cells in coronary vessels attenuated the increase in LVDP and +/-dp/dt(max) at the beginning of Fe-HQ perfusion. It is suggested that L-Arg aggravates the iron-induced cardiac dysfunction, NO can mediate the iron-induced toxicity in heart, and endothelial cells in coronary vessels play an important role in the early stage of the effect of iron.
Animals ; Arginine ; pharmacology ; Coronary Vessels ; cytology ; Creatine Kinase ; metabolism ; Endothelial Cells ; drug effects ; Heart ; drug effects ; Iron ; toxicity ; L-Lactate Dehydrogenase ; metabolism ; Malondialdehyde ; metabolism ; Myocardium ; metabolism ; Myocytes, Cardiac ; cytology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Rats

AIMWhether hemin, a heme oxygenase 1 (HO-1) inducer, reduces ischemia/reperfusion injury and whether NO synthase (NOS) and PKC are involved in the cardioprotective effects were investigated in the present study.

METHODSThe Langendorff model of isolated rat heart was used. The ventricular function, infarct size, LDH and CK during ischemia/reperfusion period were also observed.

RESULTS(1) After intraperitoneal injection of hemin (50 mg/kg) for 24 h, COHb concentration in rat blood enhanced. He-min preconditioning prevented the increase in LVEDP, decrease in LVDP and +/- dP/dt(max) in the isolated ischemia/reperfusion (ischemia for 30 main and subsequent reperfusion for 2 h) rat hearts. The leakage of LDH and CK in the coronary effluent was significantly declined in hemin-treated rat hearts. And the infarct size was als reduced. (2) By using an inhibitor of NOS NG-nitro-L-arginine methyl ester before the administration of hemin could inhibit the protection induced by hemin. (3) Administration of an inhibitor of protein kinase C chelerythrine (1 mg/kg) before hemin preconditioning could also abolish the cardioprotection induced by hemin.

CONCLUSIONThese data suggest that the involvement of NO synthase and protein kinase C have been implicated in hemin-induced delayed cardioprotection in isolated rat hearts.

Animals ; Heme Oxygenase-1 ; metabolism ; Hemin ; pharmacology ; Male ; Myocardial Reperfusion Injury ; metabolism ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide Synthase ; metabolism ; Protein Kinase C ; metabolism ; Rats ; Rats, Sprague-Dawley