Expression of heme oxygenase-1 in type II pneumocytes protects against heatstroke-induced lung damage.

Heatstroke (HS) is an acute clinical disease characterized by abnormal hyperthermia and multi-organ dysfunction. Heme oxygenase (HO)-1, also called heat shock protein (HSP)32, is induced by hyperthermia and also plays protective roles in many lung disease models. Based on this phenomenon, we investigated the protective role of endogenous HO-1 in heat-induced lung damage in rats. Male Sprague-Dawley (SD) rats were separated into three groups: (a) normothermic sham, (b) HS, and (c) SnPP (inhibitor of HO-1) pretreatment rats. In the HS group, rats were killed at various time points (1, 3, 6, and 12 h after heat exposure) in order to analyze messenger ribonucleic acid (mRNA) and protein levels. Lung sections were examined for tissue damage and localization of HO-1 using immunofluorescence double labeling. We found that HS induced lung pathology (congested and thickened lung septa). The level of HO-1 mRNA was increased at 1 h, and the protein level peaked at 6 h after heat exposure. Pretreatment with SnPP (tin-protoporphyrin IX, 30 mg/kg, intraperitoneal injection for 1 h before heat exposure) aggravated the lung damage. Furthermore, we demonstrated HO-1 expression in lung type II pneumocytes. Our results suggest that endogenous HO-1 is protective against HS-induced lung damage. Induction of HO-1 may be a potential therapeutic strategy for treating heat-related diseases.

The contribution of carbon monoxide to vascular tonus.

OBJECTIVE: The aim of this descriptive study was to examine the contribution of CO in the maintenance of vascular tonus in different organs and different vessel segments; the underlying mechanism of CO-induced vasodilation was investigated. METHODS: Sixty Wistar albino rats, aged 6-8 months, were used in this study. Response to CO by isolated arteries from the thoracic and abdominal aorta and mesenteric, renal, gastrocnemius, and gracilis muscles as well as heart, lung, and brain vascular beds was endogenously and exogenously studied using organ baths or myograph. In addition, HO-2 protein expression was assessed using Western blot analysis in isolated vessel segments. RESULTS: Although CO was shown to contribute to the regulation of vascular tonus in all feed arteries except those of the gracilis vascular bed, no effect was observed in the resistance arteries, with the sole exception of the pial artery. No relationship between HO-2 protein level and CO contribution to endogenous vascular tonus was observed. CONCLUSIONS: While the vasodilator effect of CO in vessels smaller than 600 µm in diameter was found to be mediated via potassium channels, in vessels larger than 600 µm in diameter, the effect was through both the potassium channels and the cGMP pathway.

Dominant Role for Regulatory T Cells in Protecting Females Against Pulmonary Hypertension.

RATIONALE: Pulmonary arterial hypertension (PH) is a life-threatening condition associated with immune dysregulation and abnormal regulatory T cell (Treg) activity, but it is currently unknown whether and how abnormal Treg function differentially affects males and females. OBJECTIVE: To evaluate whether and how Treg deficiency differentially affects male and female rats in experimental PH. METHODS AND RESULTS: Male and female athymic rnu/rnu rats, lacking Tregs, were treated with the VEGFR2 (vascular endothelial growth factor receptor 2) inhibitor SU5416 or chronic hypoxia and evaluated for PH; some animals underwent Treg immune reconstitution before SU5416 administration. Plasma PGI2 (prostacyclin) levels were measured. Lung and right ventricles were assessed for the expression of the vasoprotective proteins COX-2 (cyclooxygenase 2), PTGIS (prostacyclin synthase), PDL-1 (programmed death ligand 1), and HO-1 (heme oxygenase 1). Inhibitors of these pathways were administered to athymic rats undergoing Treg immune reconstitution. Finally, human cardiac microvascular endothelial cells cocultured with Tregs were evaluated for COX-2, PDL-1, HO-1, and ER (estrogen receptor) expression, and culture supernatants were assayed for PGI2 and IL (interleukin)-10. SU5416-treatment and chronic hypoxia produced more severe PH in female than male athymic rats. Females were distinguished by greater pulmonary inflammation, augmented right ventricular fibrosis, lower plasma PGI2 levels, decreased lung COX-2, PTGIS, HO-1, and PDL-1 expression and reduced right ventricular PDL-1 levels. In both sexes, Treg immune reconstitution protected against PH development and raised levels of plasma PGI2 and cardiopulmonary COX-2, PTGIS, PDL-1, and HO-1. Inhibiting COX-2, HO-1, and PD-1 (programmed death 1)/PDL-1 pathways abrogated Treg protection. In vitro, human Tregs directly upregulated endothelial COX-2, PDL-1, HO-1, ERs and increased supernatant levels of PGI2 and IL-10. CONCLUSIONS: In 2 animal models of PH based on Treg deficiency, females developed more severe PH than males. The data suggest that females are especially reliant on the normal Treg function to counteract the effects of pulmonary vascular injury leading to PH.

Heme oxygenase levels and metaflammation in benign prostatic hyperplasia patients.

PURPOSE: To investigate the relationship between intra-prostatic levels of heme oxygenase (HO), metaflammation in benign prostatic hyperplasia (BPH) tissue in patients with MetS and moderate-severe lower urinary tract symptoms (LUTS). METHODS: Between January 2012 and June 2013, 132 consecutive patients, who underwent transurethral resection of the prostate for moderate-severe LUTS, secondary to clinical BPH, were enrolled. Prostate samples were investigated for the presence of an inflammatory infiltrate, according to the Irani score, and for HO-1 and HO-2 levels measurements. Patients were evaluated for the presence of metabolic syndrome (MetS) defined by the International Diabetes Federation. RESULTS: We observed that subjects with MetS exhibited greater Irani score (3.0 vs. 2.0; p < 0.05), Irani grade (2.0 vs. 1.0; p < 0.05) and lower value of HO-1 (4.55 vs. 6.01; p < 0.05) and HO-2 (0.81 vs. 2.66; p < 0.05). HO-1 (3.91 vs. 5.67; p < 0.05) and HO-2 (1.06 vs. 1.37; p < 0.05) were significantly reduced in patients with high intra-prostatic inflammation (Irani score ≥4). At the multivariate logistic regression analysis, HO-1 reduction (OR 0.588; p < 0.01), waist circumference (OR 1.09; p < 0.01), triglycerides (OR 1.013; p < 0.05) and HDL (OR 0.750; p < 0.05) were independent predictors of high intra-prostatic inflammation. We also found that HO-1 reduction (OR 0.598; p < 0.01) and the presence of MetS (OR 34.846; p < 0.01) were associated with Irani score ≥4. CONCLUSION: MetS-induced inflammation may play a key role in BPH. In detail, prostate metaflammation is inversely related to intra-prostatic HO-1 levels, serum HDL and positively with triglycerides.

A novel and sensitive assay for heme oxygenase activity.

Heme oxygenase (HO) is a renoprotective protein in the microsome that degrades heme and produces biliverdin. Biliverdin is then reduced to a potent antioxidant bilirubin by biliverdin reductase in the cytosol. Because HO activity does not necessarily correlate with HO mRNA or protein levels, a reliable assay is needed to determine HO activity. Spectrophotometric measurement is tedious and requires a relatively large amount of kidney samples. Moreover, bilirubin is unstable and spontaneously oxidized to biliverdin in vitro. We developed a novel and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify biliverdin to measure HO activity in mice. Biliverdin and its internal standard, a deuterated biliverdin-d4, have MS/MS fragments with m/z transitions of 583 to 297 and 587 to 299, respectively. We prepared lysates of mouse kidneys, and added excess hemin, NADPH, and bilirubin oxidase to convert all bilirubin produced to biliverdin. After 30-min incubation at 37 or 4°C, the samples were analyzed by LC-MS/MS. The difference in the amount of biliverdin between the two temperatures is HO activity. Treating mice with cobalt protoporphyrin, which induces the expression of HO, increased HO activity as determined by biliverdin production. Measuring the production of biliverdin using LC-MS/MS is a more sensitive and specific way to determine HO activity than the spectrophotometric method and allows the detection of subtle changes in renal or other HO activity.

Light-emitting diode irradiation promotes donor site wound healing of the free gingival graft.

BACKGROUND: This study aims to evaluate the effect of light-emitting diode (LED) light irradiation on the donor wound site of the free gingival graft. METHODS: Rat gingival fibroblasts were chosen to assess the cellular activities and in vitro wound healing with 0 to 20 J/cm(2) LED light irradiation. Seventy-two Sprague-Dawley rats received daily 0, 10 (low-dose [LD]), or 20 (high-dose [HD]) J/cm(2) LED light irradiation on the opened palatal wound and were euthanized after 4 to 28 days; the healing pattern was assessed by histology, histochemistry for collagen deposition, and immunohistochemistry for tumor necrosis factor (TNF)-α infiltration. The wound mRNA levels of heme oxygenase-1 (HO-1), TNF-α, the receptor for advanced glycation end products, vascular endothelial growth factor, periostin, Type I collagen, and fibronectin were also evaluated. RESULTS: Cellular viability and wound closure were significantly promoted, and cytotoxicity was inhibited significantly using 5 J/cm(2) LED light irradiation in vitro. The wound closure, reepithelialization, and collagen deposition were accelerated, and sequestrum formation and inflammatory cell and TNF-α infiltration were significantly reduced in the LD group. HO-1 and TNF-α were significantly upregulated in the HD group, and most of the repair-associated genes were significantly upregulated in both the LD and HD groups at day 7. Persistent RAGE upregulation was noted in both the LD and HD groups until day 14. CONCLUSION: LED light irradiation at 660 nm accelerated palatal wound healing, potentially via reducing reactive oxygen species production, facilitating angiogenesis, and promoting provisional matrix and wound reorganization.

Soft-tissue wound healing by anti-advanced glycation end-products agents.

The blocking of advanced glycation end-products (AGE) has been shown to reduce diabetic complications and control periodontitis. This study investigated the pattern of palatal wound-healing after graft harvesting under the administration of aminoguanidine (AG), an AGE inhibitor, or N-phenacylthiazolium bromide (PTB), a glycated cross-link breaker. Full-thickness palatal excisional wounds (5.0 x 1.5 mm(2)) were created in 72 Sprague-Dawley rats. The rats received daily intraperitoneal injections of normal saline (control), AG, or PTB and were euthanized after 4 to 28 days. The wound-healing pattern was assessed by histology, histochemistry for collagen matrix deposition, immunohistochemistry for AGE and the AGE receptor (RAGE), and the expression of RAGE, as well as inflammation- and recovery-associated genes. In the first 14 days following AG or PTB treatments, wound closure, re-epithelialization, and collagen matrix deposition were accelerated, whereas AGE deposition, RAGE-positive cells, and inflammation were reduced. RAGE and tumor necrosis factor-alpha were significantly down-regulated at day 7, and heme oxygenase-1 was persistently down-regulated until day 14. The levels of vascular endothelial growth factor, periostin, type I collagen, and fibronectin were all increased at day 14. In conclusion, anti-AGE agents appeared to facilitate palatal wound-healing by reducing AGE-associated inflammation and promoting the recovery process.

Nandrolone attenuates aortic adaptation to exercise in rats.

AIMS: In this study, we investigated the interaction between exercise-induced mitochondrial adaptation of large vessels and the effects of chronic anabolic androgenic steroids (AASs). METHODS AND RESULTS: Four groups of Sprague-Dawley rats were studied: (i) sedentary, (ii) sedentary + nandrolone-treated, (iii) aerobic exercise trained, and (iv) trained + nandrolone-treated. Aerobic training increased the levels of aortic endothelial nitric oxide synthase (eNOS) and heme oxygenase-1 (HO-1) in accordance with improved acetylcholine-induced vascular relaxation. These beneficial effects were associated with induction of mitochondrial complexes I and V, increased mitochondrial DNA copy number, and greater expression of transcription factors involved in mitochondrial biogenesis/fusion. We also observed enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of beclin1 and autophagy-related protein-7 (ATG7). The levels of thiobarbituric acid-reactive substances and protein carbonyls remained unchanged, whereas significant increases in catalase and mitochondrial manganese superoxide dismutase (MnSOD) levels were observed in the aortas of trained animals, when compared with sedentary controls. Nandrolone increased oxidative stress biomarkers and inhibited exercise-induced increases of eNOS, HO-1, catalase, and MnSOD expression. In addition, it also attenuated elevated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and mitofusin-2 expression, and further up-regulated LC3II conversion, beclin1, ATG7, and dynamin-related protein-1 expression. CONCLUSION: These results demonstrate that nandrolone attenuates aortic adaptations to exercise by regulating mitochondrial dynamic remodelling, including down-regulation of mitochondrial biogenesis and intensive autophagy.

[Heme oxygenase-2 neurons brain and spinal cord of human].

Immune localization of heme oxygenase-2 in neurons of some nuclei of the spinal cord and brain stem in 6 men 18-44 years old who died from causes unrelated to injury of central nervous system was studied. Neurons with positive reaction are determined for all studied regions of the brain where their contents in various nuclei ranging from 0.5 to 16% of the total number of cells detected by methylene blue. In all the sensory nuclei there is a high proportion of small neurons with a high or moderate density of reaction produce deposits. Large cells of motor nuclei often exhibit negative or low intensive enzyme reaction.

Diazoxide attenuates ischemia/reperfusion injury via upregulation of heme oxygenase-1 after liver transplantation in rats.

AIM: To evaluate the effects of diazoxide on ischemia/reperfusion (I/R)-injured hepatocytes and further elucidate its underlying mechanisms. METHODS: Male Sprague-Dawley rats were randomized (8 for donor and recipient per group) into five groups: I/R group (4 h of liver cold ischemia followed by 6 h of reperfusion); heme oxygenase-1 (HO-1) small interfering RNA (siRNA) group (injection of siRNA via donor portal vein 48 h prior to harvest); diazoxide (DZ) group (injection of DZ via donor portal vein 10 min prior to harvest); HO-1 siRNA + DZ group; and siRNA control group. Blood and liver samples were collected at 6 h after reperfusion. The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting, and tissue morphology was examined by light and transmission electron microscopy. Serum transaminases level and cytokines concentration were also measured. RESULTS: We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA + DZ group when compared with I/R group, while the increases were prominent in the DZ group. Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA + DZ groups compared with DZ group. Serum alanine aminotransferase, aspartate transaminase, tumor necrosis factor-α and interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA + DZ groups, and decreased in the DZ group. CONCLUSION: The protective effect of DZ may be induced by upregulation of HO-1. By inhibiting expression of HO-1, this protection pretreated with DZ was abolished.

Heme oxygenase isoforms differ in their subcellular trafficking during hypoxia and are differentially modulated by cytochrome P450 reductase.

Heme oxygenase (HO) degrades heme in concert with NADPH cytochrome P450 reductase (CPR) which donates electrons to the reaction. Earlier studies reveal the importance of the hydrophobic carboxy-terminus of HO-1 for anchorage to the endoplasmic reticulum (ER) which facilitates the interaction with CPR. In addition, HO-1 has been shown to undergo regulated intramembrane proteolysis of the carboxy-terminus during hypoxia and subsequent translocation to the nucleus. Translocated nuclear HO-1 was demonstrated to alter binding of transcription factors and to alter gene expression. Little is known about the homologous membrane anchor of the HO-2 isoform. The current work is the first systematic analysis in a eukaryotic system that demonstrates the crucial role of the membrane anchor of HO-2 for localization at the endoplasmic reticulum, oligomerization and interaction with CPR. We show that although the carboxy-terminal deletion mutant of HO-2 is found in the nucleus, translocation of HO-2 to the nucleus does not occur under conditions of hypoxia. Thus, we demonstrate that proteolytic regulation and nuclear translocation under hypoxic conditions is specific for HO-1. In addition we show for the first time that CPR prevents this translocation and promotes oligomerization of HO-1. Based on these findings, CPR may modulate gene expression via the amount of nuclear HO-1. This is of particular relevance as CPR is a highly polymorphic gene and deficiency syndromes of CPR have been described in humans.

Alteration of hepatic structure and oxidative stress induced by intravenous nanoceria.

Beyond the traditional use of ceria as an abrasive, the scope of nanoceria applications now extends into fuel cell manufacturing, diesel fuel additives, and for therapeutic intervention as a putative antioxidant. However, the biological effects of nanoceria exposure have yet to be fully defined, which gave us the impetus to examine its systemic biodistribution and biological responses. An extensively characterized nanoceria (5 nm) dispersion was vascularly infused into rats, which were terminated 1 h, 20 h or 30 days later. Light and electron microscopic tissue characterization was conducted and hepatic oxidative stress parameters determined. We observed acute ceria nanoparticle sequestration by Kupffer cells with subsequent bioretention in parenchymal cells as well. The internalized ceria nanoparticles appeared as spherical agglomerates of varying dimension without specific organelle penetration. In hepatocytes, the agglomerated nanoceria frequently localized to the plasma membrane facing bile canaliculi. Hepatic stellate cells also sequestered nanoceria. Within the sinusoids, sustained nanoceria bioretention was associated with granuloma formations comprised of Kupffer cells and intermingling CD3⁺ T cells. A statistically significant elevation of serum aspartate aminotransferase (AST) level was seen at 1 and 20 h, but subsided by 30 days after ceria administration. Further, elevated apoptosis was observed on day 30. These findings, together with increased hepatic protein carbonyl levels on day 30, indicate ceria-induced hepatic injury and oxidative stress, respectively. Such observations suggest a single vascular infusion of nanoceria can lead to persistent hepatic retention of particles with possible implications for occupational and therapeutic exposures.

[The distribution of heme oxygenase-2 in the brainstem nuclei of rats].

Immunocytochemical method was used to determine the distribution of neurons expressing heme oxygenase-2 (HO-2-positive neurons) in the nuclei of various parts of the brainstem of 16 male Wistar rats. The sizes of neurons and the optical density of the product of histochemical reaction in their cytoplasm were determined in the nuclei studied. HO-2-positive neurons, differing in shape, size and numbers, were identified in the nuclei of the medulla oblongata, pons and midbrain. HO-2-positive cells were found 3-5 times more frequently in the sensory nuclei as compared to the motor ones. At the same time, relatively large number of nuclei was detected, which contained either no or a few HO-2-positive neurons.

Dietary lipids modulate methylmercury toxicity in Atlantic salmon.

This experiment aimed to study the molecular toxicity of methylmercury (MeHg) in liver, brain and white muscle of Atlantic salmon fed a diet based on fish oil (FO, high dietary n-3/n-6 ratio) compared to an alternative diet mainly based on vegetable oil (VO, low dietary n-3/n-6 ratio). Juvenile salmon were fed decontaminated diets or the FO and VO diets enriched with 5 mg Hg/kg (added as MeHg) for three months. The dietary lipid composition affected the fatty acid composition in the tissues, especially in liver and white muscle. After 84 days of exposure, the liver accumulated three times as much MeHg as the brain and white muscle. Vitamin C content and heme oxygenase, tubulin alpha (TUBA) and Cpt1 transcriptional levels all showed significant effects of MeHg exposure in the liver. TBARS, α-tocopherol, γ-tocopherol, and the transcriptional levels of thioredoxin, heme oxygenase, TUBA, PPARB1, D5D and D6D showed an effect of dietary lipid composition in liver tissue. Effects of dietary lipids were observed in brain tissue for MT-A, HIF1, Bcl-X and TUBA. Interaction effects between MeHg exposure and dietary lipid composition were observed in all tissues. Our data suggest that dietary fats have modulating effects on MeHg toxicity in Atlantic salmon.

[Expression of heme oxygenase-1 and inducible nitric oxide synthase in the lungs of hyperoxia-exposed preterm rats].

OBJECTIVE: To study the expression and the role of heme oxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) in preterm rats with hyperoxia-induced lung injuries. METHODS: Sixty-four three-day-old preterm Sprague-Dawley rats were randomly assigned to a hyperoxia group (90% oxygen exposure) and a control group (room air exposure), with 32 rats in each group. After 3 days or 7 days of exposure, the lung activity of HO-1 and nitric oxide (NO) contents in bronchoalveolar lavage fluid (BALF), pulmonary histopathologic changes, and the cellular distribution and expression of HO-1 and iNOS in the lungs were measured. RESULTS: After 3 days and 7 days of exposure, the hyperoxia group showed acute lung injuries characterized by the presence of hyperaemia, red cell extravasation and inflammatory infiltration. The NO contents in BALF and the iNOS expression in the lungs increased significantly in the hyperoxia group compared with those in the control group 3 and 7 days after exposure. The expression of HO-1 in macrophages in the lungs increased significantly in the hyperoxia group compared with that in the control group 3 and 7 days after exposure. The NO contents in BALF and the iNOS and HO-1 expression in the lungs increased significantly 7 days after hyperoxia exposure compared with 3 days after hyperoxia exposure. CONCLUSIONS: iNOS and HO-1 levels in the lungs increase in preterm rats with hyperoxia-induced lung injuries, suggesting that iNOS and HO-1 may play roles in hyperoxia-induced pulmonary injuries.

Heme oxygenase regulates renal arterial resistance and sodium excretion in cirrhotic rats.

BACKGROUND & AIMS: Heme oxygenase (HO) catabolizes heme into biliverdin, carbon monoxide (CO), and free iron. CO generated in endothelial and smooth muscle layers of blood vessels modulates vascular tone by inducing relaxation of vascular smooth muscle cells. The aim of this study was to verify the role played by HO in regulating renal arterial resistance and Na(+) excretion in cirrhosis. METHODS: Twenty control rats and 20 rats with CCl(4)(-) induced cirrhosis, 10 of which were chronically treated with the HO inducer cobalt-protoporphyrin (CoPP), were studied. Pressurized renal interlobar arteries were challenged with increasing doses of phenylephrine (PE) and acetylcholine (ACh). Dose-response curves were evaluated under basal conditions and after inhibition of HO with chromium-mesoporphyrin (CrMP). HO-1 (inducible form) and HO-2 (constitutive form) expression was measured in the main and interlobar renal arteries. Serum and urinary levels of Na(+) and creatinine were also evaluated. RESULTS: In renal interlobar arteries from cirrhotic rats, the response to PE was increased, while that to ACh was blunted. After HO inhibition, the responsiveness to these vasoactive substances was comparable in the two groups. In cirrhotic rats, HO-1 expression was impaired in the main and the interlobar renal arteries. Chronic HO induction normalized the response to the vasoconstrictor, but not to the vasodilator. Cirrhotic rats treated with CoPP showed higher urinary Na(+) concentration and fractional Na(+) excretion, compared to both untreated cirrhotic and control rats. CONCLUSIONS: In cirrhotic rats, an impaired HO-1 expression promotes vasoconstriction of renal interlobar arteries. Chronic HO induction normalizes the sensitivity to PE and promotes Na(+) excretion.

Sinomenine pretreatment attenuates cold ischemia/reperfusion injury in rats: the role of heme oxygenase-1.

Ischemia/reperfusion (I/R) injury can be characterized as an inflammatory response including recruitment of inflammatory cells to a post-ischemic organ or tissue and a cascade of mediators. Sinomenine (SIN), a pure alkaloid extracted from the Chinese medical plant Sinomenium acutum, has been used to treat various inflammatory diseases including rheumatism and arthritis. However, whether SIN can attenuate I/R injury has not previously been examined. Using a syngeneic orthotopic liver transplantation model in rats, we investigated the effect of SIN on hepatic I/R injury, in particular its effect on heme oxygenase-1 (HO-1) induction and its hepatocellular protective effect. To our knowledge, our results were the first to show that: (a) SIN pretreatment was able to induce HO-1 expression in donor livers in a dose dependent manner; (b) SIN pretreatment protected the liver graft from cold I/R injury; and (c) the protective effect of SIN was, at least in part, mediated by HO-1, as proved by the fact that inhibiting HO-1 activity with zinc protoporphyrin (ZnPP) reduced the protection. Thus, SIN deserves further exploration as a novel agent to attenuate I/R injury.

N-acetylcysteine attenuates glycerol-induced acute kidney injury by regulating MAPKs and Bcl-2 family proteins.

BACKGROUND: Rhabdomyolysis-induced acute kidney injury (AKI) accounts for about 10 to 40% of all cases of AKI. It is known that N-acetylcysteine (NAC) is effective in various experimental renal injury models; however, little information is available about the rat model of glycerol-induced rhabdomyolysis. In this study, we hypothesize that NAC plays a renoprotective role via the anti-apoptotic pathway. METHODS: Male Sprague-Dawley rats were divided into four groups: (i) saline control group, (ii) NAC-treated group (N-acetylcysteine) (150 mg/kg), (iii) glycerol-treated group (50%, 8 ml/kg, IM) and (iv) NAC plus glycerol-treated group. Rats were sacrificed at 24 h after glycerol injection, and the blood and renal tissues were harvested. RESULTS: Glycerol administration caused severe renal dysfunction, which included marked renal oxidative stress, significantly increased blood urea nitrogen (BUN) and serum creatinine levels. Histopathological findings, such as cast formation and tubular necrosis, confirmed renal impairment. We noted a marked activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but not p-38, in the glycerol-treated group. We also observed high expression of Bax and Bad but only weak expression of Bcl-2 and Bcl-xL in the glycerol-treated group. However, NAC pretreatment significantly improved renal function and decreased the activation of ERK, JNK, Bax and Bad, whereas it increased Bcl-2 and Bcl-xL. CONCLUSION: These results demonstrate that NAC protects against renal dysfunction, morphological damage and biochemical changes via the anti-apoptotic pathway in the glycerol-induced rhabdomyolysis model in rats.

Immunolocalisation of heme oxygenase isoforms in human nasal polyps.

BACKGROUND: Carbon monoxide is an endogenous vasodilator gas produced by the enzyme heme oxygenase (HO). HO is expressed in human nasal mucosa, but its pathophysiological role in nasal inflammatory diseases is not fully understood. The aim of this study was to detect and compare the expression of HO-1 and -2 isoforms in nasal polyps with normal nasal mucosa. METHODS: Immunohistochemical analysis using antibodies specific for HO-1 and -2 was conducted on nasal polyps from nine patients with allergic nasal polyposis, and on normal nasal mucosa from six controls. RESULTS: Intense HO-1 immunoreactivity was observed in nasal polyp epithelium but was absent in normal nasal mucosa. HO-2 staining was observed in respiratory epithelium, vascular endothelium and seromucous glands, with no difference observed between nasal polyps and normal nasal mucosa. CONCLUSIONS: HO-1 expression is up-regulated in nasal polyp epithelium, supporting the theory that respiratory epithelium plays a role in the pathogenesis of nasal polyposis.

Nitric oxide and carbon monoxide synthesizing enzymes and soluble guanylyl cyclase within neurons of adult human cardiac ganglia.

Nitric oxide and carbon monoxide are diffusible gas messengers, synthesized by nitric oxide synthase or heme oxygenase 2, respectively, that can activate soluble guanylyl cyclase in adjacent cells. Nitric oxide and carbon monoxide neuromodulation in cardiac ganglia has been demonstrated. However, identification of nitric oxide or carbon monoxide in human cardiac ganglia needs to be confirmed as suggested from animal model studies. Immunohistochemistry was used to demonstrate neuronal nitric oxide synthase, heme oxygenase 2, and soluble guanylyl cyclase immunoreactivity within neurons of adult human cardiac ganglia. Nitric oxide synthase immunoreactivity was present in 37% of neurons within cardiac ganglia, heme oxygenase 2 immunoreactivity in 79%, and soluble guanylyl cyclase in 53%. Our findings support the hypothesis that nitric oxide and carbon monoxide are modulators of neurotransmission in cardiac ganglia and in neural control of the adult human heart.