Melatonin mitigates vincristine-induced peripheral neuropathy by inhibiting TNF-α/astrocytes/microglial cells activation in the spinal cord of rats, while preserving vincristine's chemotherapeutic efficacy in lymphoma cells.

Vincristine (VCR), an anti-tubulin chemotherapy agent, is known to cause peripheral and central nerve damage, inducing severe chemotherapy-induced peripheral neuropathy (CIPN). Although melatonin has been recently recognized for its potential anti-neuropathic effects, its efficacy in countering VCR-induced neuropathy remains unclear. This study examines the neuroprotective potential of melatonin against VCR-induced neuropathy using a rat model. Neuropathic pain was induced through 10 VCR injections (0.1 mg/kg/day i.p.), administered in two five-day cycles with a two-day break. Melatonin treatment started two days before VCR administration and continued daily throughout the experiment. Rats were assigned to five groups: control, VCR, and three melatonin-treated groups receiving VCR with melatonin (5, 10, or 20 mg/kg/day i.p.). We assessed mechanical (von-Frey and Randall-Selitto tests) and thermal (hot-plate and tail-flick tests) hyperalgesia, motor coordination (rotarod test), and sciatic nerve conduction velocity (NCV). Changes in body weight, spinal cord histopathology (H&E), and proinflammatory markers (TNF-α, IL-1ß, and IL-6), reactive astrocytes (GFAP) and microglial cells (IBA-1) were also assessed, as well as spinal cord degeneration (Nissl stain) and demyelination (LFB stain and MBP). Finally, the effect of melatonin on the cytotoxic activity of VCR against EL4 lymphoma cells was assessed using an MTT assay. Our results indicated that melatonin coadministration with VCR preserved spinal cord architecture, elevated nociceptive thresholds, improved motor coordination, enhanced NCV, and maintained normal body weight gain. Melatonin also reduced inflammation, decreased reactive astrocytes and microglia, and prevented neurodegeneration and demyelination in the spinal cord. Importantly, melatonin did not affect VCR's cytotoxic activity in cancer cells.

Reposition of the anti-inflammatory drug diacerein in an in-vivo colorectal cancer model.

Excessive interleukin (IL)-6 production is a driver for malignancy and drug resistance in colorectal cancer (CRC). Our study investigated a seven-week post-treatment with the anti-inflammatory drug, Diacerein (Diac), alone or in combination with 5-fluorouracil (5-FU), using a 1,2-dimethylhydrazine (DMH) rat model of CRC. Diac alone and 5-FU+Diac reduced serum levels of carcino-embryonic antigen (CEA), while all regimens decreased serum levels of colon cancer-specific antigen (CCSA), a more specific CRC biomarker. Additionally, Diac, 5-FU and their combination suppressed colonic content/gene expression of IL-6, its downstream oncogene, Kirsten rat sarcoma viral oncogene homolog (K-Ras), and consequently Notch intracellular domain and nuclear factor-kappa B (NF-κB) p65. In turn, NF-κB downstream factors, viz., matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), c-Myc, and B-cell lymphoma-2 (Bcl-2) were also downregulated, while E-cadherin was elevated. Additionally, the drugs reduced the immunoreactivity of CD31 to prove their anti-angiogenic effect, while the TUNEL assay confirmed the apoptotic effect. The apoptotic effect was confirmed by transferase dUTP nick-end labeling assay. Moreover, these drugs inhibited colon content of p-Akt, ß-catenin, and cyclin D1 immunoreactivity. The drugs also activated the tumor suppressor glycogen synthase kinase 3- ß (GSK3-ß) and upregulated the expression of the Nur77 gene, which represents the second arm of IL-6 signaling. However, only 5-FU upregulated miR-200a, another K-Ras downstream factor. The in-vitro cytotoxic and migration/invasion assays verified the molecular trajectories. Accordingly, we evaluated the antineoplastic effect of Diac alone and its possible chemosensitization effect when added to 5-FU. This combination may target critical oncogenic pathways, including the IL-6/K-Ras/Notch/NF-κB p65 axis, p-Akt/GSK3-ß/ß-catenin/cyclin D-1 hub, and Nur77.

Studies on the antidiabetic activities of Momordica charantia fruit juice in streptozotocin-induced diabetic rats.

CONTEXT: Momordica charantia Linn (Cucurbitaceae) (MC) is used in folk medicine to treat various diseases including diabetes mellitus. OBJECTIVE: This study investigates the antidiabetic activities of Momordica charantia (bitter gourd) on streptozotocin-induced type 2 diabetes mellitus in rats. MATERIALS AND METHODS: Male Wister rats were randomly assigned to 4 groups. Group I, Normal control; Group II, STZ diabetic; Group III and IV, Momordica charantia fruit juice was orally administered to diabetic rats (10 mL/kg/day either as prophylaxis for 14 days before induction of diabetes then 21 days treatment, or as treatment given for 21 days after induction of diabetes). The effects of MC juice were studied both in vivo and in vitro by studying the glucose uptake of isolated rat diaphragm muscles in the presence and absence of insulin. Histopathological examination of pancreas was also performed. RESULTS: This study showed that MC caused a significant reduction of serum glucose (135.99 ± 6.27 and 149.79 ± 1.90 vs. 253.40* ± 8.18) for prophylaxis and treatment respectively, fructosamine (0.99 ± 0.01 and 1.01 ± 0.04 vs. 3.04 ± 0.07), total cholesterol, triglycerides levels, insulin resistance index (1.13 ± 0.08 and 1.19 ± 0.05 vs. 1.48 ± 1.47) and pancreatic malondialdehyde content (p < 0.05). While it induced a significant increase of serum insulin (3.41 ± 0.08 and 3.28 ± 0.08 vs. 2.39 ± 0.27), HDL-cholesterol, total antioxidant capacity levels, ß cell function percent, and pancreatic reduced glutathione (GSH) content (p < 0.05) and improved histopathological changes of the pancreas. It also increased glucose uptake by diaphragms of normal (12.17 ± 0.60 vs. 9.07 ± 0.66) and diabetic rats (8.37 ± 0.28 vs. 4.29 ± 0.51) in the absence and presence of insulin (p < 0.05). CONCLUSIONS: Momordica charantia presents excellent antidiabetic and antioxidant activities and thus has great potential as a new source for diabetes treatment whether it is used for prophylaxis or treatment.

Genistein and/or sulfasalazine ameliorate acetic acid-induced ulcerative colitis in rats via modulating INF-γ/JAK1/STAT1/IRF-1, TLR-4/NF-κB/IL-6, and JAK2/STAT3/COX-2 crosstalk.

Ulcerative Colitis (UC) is a chronic idiopathic inflammatory bowel disease in which the colon's lining becomes inflamed. Exploring herbal remedies that can recover mucosal damage is becoming popular in UC. The study aims to investigate the probable colo-protective effect of a natural isoflavone, genistein (GEN), and/or a drug, sulfasalazine (SZ), against acetic acid (AA)-induced UC in rats, in addition to exploring the possible underlying mechanisms. UC was induced by the intrarectal installation of 1-2 ml of 5% diluted AA for 24 h. Ulcerated rats were allocated into the disease group and three treated groups, with SZ (100 mg/kg), GEN (100 mg/kg), and their combination for 14 days, besides the control groups. The anti-colitic efficacy of GEN and/or SZ was evidenced by hindering the AA-induced weight loss, colon edema, and macroscopic scores, besides reduced disease activity index and colon weight/length ratio. Furthermore, treatments attenuated the colon histopathological injury scores, increased the number of goblet cells, and lessened fibrosis. Both treatments reduced the up-regulation of INF-γ/JAK1/STAT1 and INF-γ /TLR-4/ NF-κB signaling pathways and modulated the IRF-1/iNOS/NO and IL-6/JAK2/STAT3/COX-2 pathways and consequently, reduced the levels of TNF-α and IL-1ß. Moreover, both treatments diminished oxidative stress, which appeared by reducing the MPO level and elevating the SOD activity, and hindered apoptosis; proved by the decreased immunohistochemical expression of caspase-3. The current findings offer novel insights into the protective effects of GEN and suggest a superior benefit of combining GEN with SZ, over either drug alone, in the UC management.

PPAR-γ agonist, pioglitazone, reduced oxidative and endoplasmic reticulum stress associated with L-NAME-induced hypertension in rats.

Peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, pioglitazone, is used clinically to improve the glycemic state in patients with type-2 diabetes mellitus. Independent of its blood glucose-lowering properties, pioglitazone ameliorates different cardiovascular disorders. The aim of the present study was to investigate the effect of pioglitazone on cardiovascular complications of N-nitro-L-arginine methyl ester (L-NAME)-induced hypertension and to determine the role of oxidative and endoplasmic reticulum (ER) stress in its activity. Nitric oxide (NO) deficiency induced by chronic L-NAME administration was associated with high blood pressure (BP) and cardiac hypertrophy. L-NAME induced oxidative stress as indicated by reduced glutathione (GSH) levels, superoxide dismutase (SOD) and catalase activities as well as increased malondialdehyde (MDA) levels. Furthermore, L-NAME increased the expression of ER stress markers, activating transcription factor-4 (ATF-4) and C/EPBα-homologous protein-10 (CHOP-10) in both heart and aorta of hypertensive rats. Activation of PPAR-γ by pioglitazone reduced BP, restored the blunted NO levels, increased endothelial NO synthase (eNOS) expression, and restored the antioxidant status of L-NAME-induced hypertensive rats. Moreover, the antihypertensive activity of pioglitazone was associated with a reduction in ER stress and this effect was PPAR-γ dependent. Interestingly, the effect of ER stress inhibitor, 4-phenylbutyric acid (4-PBA) and antioxidant, N-acetylcysteine (NAC), on BP, NO availability, oxidative stress and ER stress mimics the activity of pioglitazone. Taken together, our data suggests that PPAR-γ is a potential target to inhibit vascular complications and cardiac damage associated with NO-deficient HTN and puts more emphasis on the importance of ER stress in regulating PPAR-γ activity.

Raspberry ketone and Garcinia Cambogia rebalanced disrupted insulin resistance and leptin signaling in rats fed high fat fructose diet.

AIM: Obesity is a continually growing pandemic leading to many diseases that affect the overall quality of life. The widely marketed Garcinia cambogia (GC) and Raspberry ketone (RK) were used in this study. Despite their known dietetic effect, however, the metabolomic/signaling pathways involved in this effect are not fully elucidated. Hence, our study comprehends the possible trajectories of their combination against obesity and insulin resistance in addition to exploring their combination merit. MATERIALS AND METHODS: Adult male Wistar rats were divided into 5 groups; viz., normal diet (ND), high fat fructose diet (HFFD), HFFD+GC (600mg/kg), HFFD+RK (55mg/kg) and HFFD+GC+RK. To assess our aim, we determined their effect on body weight, IPGTT, glucose homeostasis (glucose, insulin, HOMA IR), lipid profile parameters and SREBP-1c, oxidative stress markers, insulin and leptin signaling pathways (p-IRS-1/p-AKT/GLUT-4, and leptin/STAT-3), as well as liver and adipose tissue histopathology. RESULTS: GC/RK combinationcaused weight loss, corrected the disturbed glucose and insulin homeostasis, raised serum levels of HDL anddecreased all other lipid profile parameters. They also increased Nrf-2 expression, ad GSH, as well as p-IRS-1/p-Akt/GLUT-4 cue, while they decreased MDA, leptin/STAT-3 and SREBP-1c content compared to the HFFD group. Furthermore, the GC/RK combination abolished apoptosis, fatty changes and inflammation in hepatocytes and decreased sclerotic blood vessels and congestion in adipose tissue. CONCLUSION: Our study highlights the involvement ofp-IRS-1/p-Akt/GLUT-4, leptin/STAT-3 and SREBP-1c signaling trajectories in the beneficial combination of GC and RK, besides, the efficient rebalance of the redox status, insulin resistance and tissue fat deposition confirmed histopathologically.

Protective effects of thymoquinone on D-galactose and aluminum chloride induced neurotoxicity in rats: biochemical, histological and behavioral changes.

OBJECTIVES: Thymoquinone (TQ), the main active ingredient in Nigella sativa oil, exhibits various bioactivities. This study aimed to investigate the effect of TQ on neurobehavioral and neuropathological alterations induced by aluminum trichloride (AlCl3) and D-galactose (D-gal)-in male rats and to explore the related mechanisms. METHODS: D-gal (60 mg/kg day) and AlCl3 (10 mg/kg day) were given intraperitoneally (i.p.) once daily for 42 days and after 4 weeks TQ was concomitantly administered intragastrically (i.g.) (20 mg/kg/day) once daily for 14 days. Then, memory function was evaluated by Morris water maze test (MWM). Superoxide dismutase (SOD), Total antioxidant capacity (TAC), Acetylcholinesterase (AChE) activities, and malondialdehyde (MDA), nitric oxide (NO), brain-derived neurotrophic factor (BDNF), and B-cell lymphoma-2 (Bcl-2) levels in whole brain were assessed with the biochemical technique. Tumor necrosis factor-alpha (TNF-α) and Acetylcholine (ACh) were also assessed using an immunohistochemical technique. RESULTS: Administration of TQ significantly improved cognition. In addition, TQ significantly increased SOD and TAC and decreased AChE activities. It also decreased MDA and NO levels as well as TNF-α immunoreactivity and increased BDNF and Bcl-2 levels as well as ACh immunoreactivity. DISCUSSION: Our results indicate that TQ prevents D-gal/AlCl3-induced cognitive decline by enhancing cholinergic function and synaptic plasticity as well as attenuation of oxidative damage, neuronal apoptosis, and neuroinflammation. These results indicate that TQ holds potential for neuroprotection and may be a promising approach for the treatment of neurodegenerative disorders.

The anorectic agent, lorcaserin, disturbs estrous cyclicity and produces endometrial hyperplasia without affecting ovarian population in female rats.

AIMS: The present study aims to investigate the effect of the new anorectic agent, lorcaserin, on estrous cyclicity, reproductive hormones and folliculogenesis in female mature rats. MATERIALS AND METHODS: Rats were divided into four groups; Group i: control group. Group ii-iv: rats treated with lorcaserin (5, 10 or 30mg/kg/day, p.o.), respectively. The treatment continued for 28days. KEY FINDINGS: Lorcaserin (5 or 10mg/kg) caused estrous cycle disturbance in 40% of treated rats while the high dose (30mg/kg) produced disturbances in 100% of the treated rats. Lorcaserin (5-30mg/kg) altered some of female hormones where it enhanced estradiol but reduced luteinizing hormone. Minimal edema with congested vessels was observed in the medulla of ovarian sections. Further, epithelial and uterine sections showed hyperplasia. SIGNIFICANCE: Taken together, the present results demonstrated that lorcaserin affected some reproductive hormones, disturbed estrous cyclicity and induced histopathological changes in the ovaries and uteri without affecting the ovarian populations. Therefore, lorcaserin should be used with caution in women of child bearing potential until adequate clinical safety data are available.

PARP inhibition ameliorates nephropathy in an animal model of type 2 diabetes: focus on oxidative stress, inflammation, and fibrosis.

Poly(ADP-ribose) polymerase (PARP) enzyme contributes to nephropathy, a serious diabetic complication which may lead to end-stage renal disease. The study aims to investigate the effect of PARP over-activation on kidney functions in a type 2 diabetic rat model. The study also tests the therapeutic use of PARP inhibitors in diabetic nephropathy. Type 2 diabetes was induced in adult male rats by high-fructose/high-fat diet and low streptozotocin dose. Then, the PARP inhibitor 4-aminobenzamide (4-AB) was administered daily for 10 weeks. At the end, urine samples were collected to measure urine creatinine, albumin, and total proteins. PARP activity, superoxide dismutase (SOD) activity, and nitrite content were measured in kidney tissue homogenate. Glucose, fructosamine, insulin, and tumor necrosis factor-alpha (TNF-α) were measured in serum. Furthermore, histological studies, collagen deposition, and immunofluorescence of nuclear factor kappa B (NFκB) and transforming growth factor beta1 (TGF-ß1) were carried out. PARP enzyme activity was significantly higher in the diabetic group and was significantly reduced by 4-AB administration. Diabetic animals had clear nephropathy indicated by proteinuria and increased albumin excretion rate (AER) which were significantly decreased by PARP inhibition. In addition, PARP inhibition increased creatinine clearance in diabetic animals and reduced renal TGF-ß1 and glomerular fibrosis. Moreover, PARP inhibition alleviated the elevated serum TNF-α level, renal NFκB, nitrite, and the decrease in SOD activity in diabetic animals. However, PARP inhibition did not significantly affect neither hyperglycemia nor insulin sensitivity. PARP enzyme inhibition alleviates diabetic nephropathy through decreasing inflammation, oxidative stress, and renal fibrosis.

PARP-1 inhibition alleviates diabetic cardiac complications in experimental animals.

Cardiovascular complications are the major causes of mortality among diabetic population. Poly(ADP-ribose) polymerase-1 enzyme (PARP-1) is activated by oxidative stress leading to cellular damage. We investigated the implication of PARP-1 in diabetic cardiac complications. Type 2 diabetes was induced in rats by high fructose-high fat diet and low streptozotocin dose. PARP inhibitor 4-aminobenzamide (4-AB) was administered daily for ten weeks after diabetes induction. At the end of study, surface ECG, blood pressure and vascular reactivity were studied. PARP-1 activity, reduced glutathione (GSH) and nitrite contents were assessed in heart muscle. Fasting glucose, fructosamine, insulin, and tumor necrosis factor alpha (TNF-α) levels were measured in serum. Finally, histological examination and collagen deposition detection in rat ventricular and aortic sections were carried out. Hearts isolated from diabetic animals showed increased PARP-1 enzyme activity compared to control animals while significantly reduced by 4-AB administration. PARP-1 inhibition by 4-AB alleviated cardiac ischemia in diabetic animals as indicated by ECG changes. PARP-1 inhibition also reduced cardiac inflammation in diabetic animals as evidenced by histopathological changes. In addition, 4-AB administration improved the elevated blood pressure and the associated exaggerated vascular contractility, endothelial destruction and vascular inflammation seen in diabetic animals. Moreover, PARP-1 inhibition decreased serum levels of TNF-α and cardiac nitrite but increased cardiac GSH contents in diabetic animals. However, PARP-1 inhibition did not significantly affect the developed hyperglycemia. Our findings prove that PARP-1 enzyme plays an important role in diabetic cardiac complications through combining inflammation, oxidative stress, and fibrosis mechanisms.

Candesartan and glycyrrhizin ameliorate ischemic brain damage through downregulation of the TLR signaling cascade.

Stroke is the second leading cause of death in industrialized countries and the most frequent cause of permanent disability in adults worldwide. The final outcome of stroke is determined not only by the volume of the ischemic core, but also by the extent of secondary brain damage inflicted to penumbral tissues by brain swelling, impaired microcirculation, and inflammation. The only drug approved for the treatment ischemic stroke is recombinant tissue plasminogen activator (rt-PA). The current study was designed to investigate the protective effects of candesartan (0.15 mg/kg, orally) and glycyrrhizin (30 mg/kg, orally) experimentally-induced ischemic brain damage in C57BL/6 mice (middle cerebral artery occlusion, MCAO) in comparison to the effects of a standard neuroprotective drug (cerebrolysin, 7.5 mg/kg, IP). All drugs were administered 30 min before and 24h after MCAO. Both candesartan and glycyrrhizin ameliorated the deleterious effects of MCAO as indicated by the improvement in the performance of the animals in behaviour tests, reduction in brain infarction, neuronal degeneration, and leukocyte infiltration. In addition, MCAO induced a significant upregulation in the different elements of the TLR pathway including TLR-2 and TLR-4, Myd88, TRIF and IRF-3 and the downstream effectors TNF-α, IL-1ß, IL-6 and NF-kB. All these changes were significantly ameliorated by treatment with candesartan and glycyrrhizin. The results of the current study represent a new indication for both candesartan and glycyrrhizin in the management of ischemic stroke with effects comparable to those of the standard neuroprotective drug cerebrolysin.

Therapeutic effect of captopril, pentoxifylline, and cordyceps sinensis in pre-hepatic portal hypertensive rats.

BACKGROUND/AIM: Portal hypertension is an important and potentially fatal complication of liver disease whereby cellular and fibrotic alterations manifest to increase portal venous pressure. The aim of this study is to investigate the effect of captopril, pentoxifylline (PTX), and cordyceps sinensis in pre-hepatic portal hypertensive rats. SETTINGS AND DESIGN: Wistar male rats were divided at random into 3 main groups: the first group: control rats. The second group: sham-operated rats and the third group: prehepatic portal hypertensive rats (PHPHT) induced by regulated pre-hepatic portal vein ligation. After 14 days, Group 3 was subdivided into 5 subgroups. Subgroup (1): portal vein-ligated (PVL) was killed at once; Subgroup (2): received distilled water for 30 days (untreated PVL group); subgroups 3-5 were treated with captopril (60 mg/kg, orally); PTX (100 mg/kg, orally); and C. sinensis (200 mg/kg, orally), respectively, as a single daily dose for 30 days. PATIENTS AND METHODS: Portal pressure, nitric oxide (NO), antioxidant enzymes, Liver enzymes, and creatinine levels were measured to evaluate the status of the liver state. RESULTS: Portal vein ligation produced significant increments in liver enzymes, NO, creatinine and portal pressure concomitant with significant decrements in glutathione content and superoxide dismutase activity. Treatment with captopril, PTX, and C. sinensis resulted in a significant reduction in liver enzymes, NO, creatinine and portal pressure and observable increase in antioxidant enzymes. CONCLUSIONS: captopril, PTX, and C. sinensis have promising effect in controlling PHPHT and reducing hyperdynamic circulatory state through reduction of portal pressure and NO level.

Effect of Cordyceps sinensis and taurine either alone or in combination on streptozotocin induced diabetes.

The present study aimed to investigate the antidiabetic effects of Cordyceps sinensis, taurine and their combination in comparison with glibenclamide both in vivo and in vitro using streptozotocin rat model. The diabetic rats were orally given glibenclamide, C. sinensis, taurine or Cordyceps and taurine combination for 21 days. Their effects were studied both in vivo and in vitro. Oral administration of Cordyceps, taurine and their combination decreased serum glucose, fructosamine, total cholesterol, triglycerides levels, insulin resistance index and pancreatic malondialdehyde content. Cordyceps significantly increased serum insulin, HDL-cholesterol, total antioxidant capacity levels, ß cell function percent, and pancreatic reduced glutathione (GSH) content. However, taurine was unable to elevate pancreatic GSH level to a significant level. These natural products and their combinations were more effective than glibenclamide in reducing insulin resistance index and they had stronger antioxidant properties. Cordyceps and taurine significantly enhanced glucose uptake by diaphragms of normal and diabetic rats in absence and presence of insulin. In conclusion, Cordyceps and taurine either alone or in combination have less potent hypoglycemic effects than glibenclamide; however, they have more ability to reduce insulin resistance and stronger antioxidant properties.

Haem oxygenase-1 induction protects against tumour necrosis factor alpha impairment of endothelial-dependent relaxation in rat isolated pulmonary artery.

BACKGROUND AND PURPOSE: Disturbances in pulmonary vascular reactivity are important components of inflammatory lung disease. Haem oxygenase-1 (HO-1) is an important homeostatic enzyme upregulated in inflammation. Here we have investigated the potentially protective effect of HO-1 against cytokine-induced impairment in pulmonary artery relaxation. EXPERIMENTAL APPROACH: Haem oxygenase-1 protein levels were assessed by immunofluorescence. HO activity was assessed by conversion of haemin to bilirubin. Rings of rat isolated pulmonary artery in organ baths were used to measure relaxant responses to the endothelium-dependent agent ACh and the endothelium-independent agent sodium nitroprusside (SNP). Production of nitric oxide (NO) and reactive oxygen species (ROS) was assessed by confocal fluorescence microscopy and fluorescent probes. KEY RESULTS: Haem oxygenase-1 protein expression was strongly induced in pulmonary artery after 24-h incubation with either haemin (5 microM) or curcumin (2 microM), accompanied by a significant increase in HO activity. Incubation with tumour necrosis factor alpha (TNFalpha, 1 ng.mL(-1), 2 h) significantly decreased relaxation of arterial rings to ACh, without affecting responses to SNP. Induction of HO-1 by curcumin or haemin protected against TNFalpha-induced hyporesponsiveness to ACh. The competitive HO inhibitor, tin protoporphyrin (20 microM), abolished the protective effect of haemin. HO-1 induction prevented a TNFalpha-induced increase in NO generation without affecting the TNFalpha-induced increase in ROS generation. HO-1 induction prevented the TNFalpha-induced decrease in ACh-stimulated NO generation. CONCLUSIONS AND IMPLICATIONS: Induction of HO-1 protected against TNFalpha impairment of endothelium-dependent relaxation in pulmonary artery, by a mechanism involving a reduction in inducible NO synthase-derived NO production.