Postconditioning with far-infrared irradiation increases heme oxygenase-1 expression and protects against ischemia/reperfusion injury in rat testis.

AIMS: Studies have shown that heme oxygenase-1 (HO-1) has a protective role in the mechanism underlying hypoxic preconditioning. We used a far-infrared radiation (FIR) heater to investigate the postconditioning protective role of HO-1 against ischemia/reperfusion (I/R) injury in rat testis. MAIN METHODS: Forty rats were used. Testis ischemia was mimicked by total obstructive clamping of testis vessels for 1, 2, or 4 h, and concomitant postconditioning with 30 min FIR or heat light during initially 30 min reperfusion. HO-1 expression and apoptosis of testis tissues were examined by immunohistochemistry and in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, respectively. HO-1 protein level and caspase-3 activity were analyzed by Western blotting. KEY FINDINGS: There was less apoptotic activity in rat testis after FIR, as determined by TUNEL assay. Higher HO-1 protein expression was observed by immunohistochemistry and Western blotting (p<0.01) in testis cells after FIR postconditioning. In contrast, caspase-3 activity was significantly higher in heat light groups, as compared with FIR groups (p<0.01). SIGNIFICANCE: FIR postconditioning attenuated I/R injury in rat testis by inducing HO-1 expression, which might have a protective role in testis apoptosis after I/R injury.

Neutrophil priming by hypoxic preconditioning protects against epithelial barrier damage and enteric bacterial translocation in intestinal ischemia/reperfusion.

Intestinal ischemia/reperfusion (I/R) induces mucosal barrier dysfunction and bacterial translocation (BT). Neutrophil-derived oxidative free radicals have been incriminated in the pathogenesis of ischemic injury in various organs, but their role in the bacteria-containing intestinal tract is debatable. Primed neutrophils are characterized by a faster and higher respiratory burst activity associated with more robust bactericidal effects on exposure to a second stimulus. Hypoxic preconditioning (HPC) attenuates ischemic injury in brain, heart, lung and kidney; no reports were found in the gut. Our aim is to investigate whether neutrophil priming by HPC protects against intestinal I/R-induced barrier damage and bacterial influx. Rats were raised in normoxia (NM) or kept in a hypobaric hypoxic chamber (380 Torr) 17 h/day for 3 weeks for HPC, followed by sham operation or intestinal I/R. Gut permeability was determined by using an ex vivo macromolecular flux assay and an in vivo magnetic resonance imaging-based method. Liver and spleen homogenates were plated for bacterial culturing. Rats raised in HPC showed diminished levels of BT, and partially improved mucosal histopathology and epithelial barrier function compared with the NM groups after intestinal I/R. Augmented cytokine-induced neutrophil chemoattractant (CINC)-1 and -3 levels and myeloperoxidase activity correlated with enhanced infiltration of neutrophils in intestines of HPC-I/R compared with NM-I/R rats. HPC alone caused blood neutrophil priming, as shown by elevated production of superoxide and hydrogen peroxide on stimulation, increased membrane translocation of cytosolic p47(phox) and p67(phox), as well as augmented bacterial-killing and phagocytotic activities. Neutrophil depletion reversed the mucosal protection by HPC, and aggravated intestinal leakiness and BT following I/R. In conclusion, neutrophil priming by HPC protects against I/R-induced BT via direct antimicrobial activity by oxidative respiratory bursts and through promotion of epithelial barrier integrity for luminal confinement of enteric bacteria.

Far infrared ray irradiation attenuates apoptosis and cell death of cultured keratinocytes stressed by dehydration.

Far infrared (FIR) irradiation has been widely applied in health promotion. The aims of this study were to investigate the protective effect of FIR irradiation on stressed keratinocytes and the signaling pathways involved. HaCaT was subjected to sorbitol dehydration with or without 40min pretreatment with FIR radiation 4h earlier. Western blots of cell lysates were analyzed for caspase-3, HO-1, BCL2, Bax, ERK, and Akt. The incidence of apoptosis was also assessed by TUNEL staining. Evaluation of cell viability was determined using MTT. mRNAs were extracted and compared using Illumina Human Ref-8 v2 BeadChips. Hyperosomotic injury of HaCaT cells caused by sorbitol resulted in increased cleaved caspase-3 expression and this effect was decreased by FIR pretreatment; these findings were confirmed by TUNEL staining and MTT tests. Pre-treatment with FIR irradiation before sorbitol-induced dehydration significantly upregulated phosphorylated Akt (p-Akt) levels and A6730, an Akt kinase inhibitor (5µM), attenuated the protective effect of FIR irradiation. A microarray study showed FIR irradiation had far less effect at the transcriptional level. FIR pretreatment attenuates apoptosis and cell death in dehydration-stressed cultured keratinocytes through the PI-3K/Akt pathway, this protective effect of FIR irradiation is not at the transcriptional level.

Simvastatin induces the expression of hemeoxygenase-1 against ischemia-reperfusion injury on the testes in rats.

We evaluate the protective role of simvastatin-induced HO-1 in remote preconditioning against testis ischemia-reperfusion (IR) injury in vivo. Simvastatin was intraperitoneally (i.p.) injected 24 h before IR injury. Testis was occluded in the right testis for 40 min and followed by 30 min of reperfusion to induce IR injury. Tin protoporphyrin (Snpp), a competitive inhibitor of hemeoxygenase, was i.p. injected 1 h before the IR injury in separate groups of rats. The rat testes were harvested 24 h later. Induction of HO-1 expression by simvastatin was significantly increased at 24 and 48 h. Rats pre-treated with simvastatin showed higher expression of HO-1 protein by Western blotting and immunohistochemistry (IHC), and presented lower caspases-3 activity by caspase-3 activity assay. TUNEL staining analysis revealed simvastatin pretreatment significantly reduced IR induced cellular apoptosis. Contrarily, the simvastatin-induced cytoprotective effect was entirely abolished by administrations of Snpp. Further, lower caspase-3 activities were also noted in simvastatin plus Snpp (SS) group than the control plus Snpp (CS) group. After IR injury, eNOS immunoreactivity was markedly increased in the germ cell and Leydig cell of testicular tissues. Pretreatment of simvastatin significantly decreased eNOS immunoreactivity in the germ cell of the tubules in the rat testes. In conclusion, we suggest HO-1 plays a protective role in IR-induced injury in the testes of rats.

Simvastatin upregulates Bcl-2 expression and protects retinal neurons from early ischemia/reperfusion injury in the rat retina.

Simvastatin has been shown to enhance the survival of retinal ganglion cells (RGCs) following ischemia-reperfusion (IR) injury by mediating the expression of stress proteins. The purpose of this study was to investigate the effect of simvastatin on retinal neurons and the expression of apoptotic proteins in a rat IR model. Wistar rats received intravitreal injection of simvastatin immediately after retinal reperfusion. Retinal ischemia was induced by increasing intraocular pressure to 150 mm Hg for 60 min. The number of viable RGCs was measured after retrograde labeling with Fluoro-Gold. Ischemia-induced apoptotic cell death was studied using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). We found that simvastatin treatment enhanced RGC survival after retinal ischemia by approximately 40% and decreased retinal neuronal apoptosis. Using western blot analysis, we found that simvastatin upregulated the expression of Bcl-2 in the retina. In contrast, the level of the protein Bax was unaffected by simvastatin treatment. Our results suggest that RGC loss induced by retinal IR may be prevented by simvastatin and that the mechanism underlying this process possibly involves an alteration in the apoptotic pathway.

Pharmacological preconditioning by low dose cobalt protoporphyrin induces heme oxygenase-1 overexpression and alleviates retinal ischemia-reperfusion injury in rats.

PURPOSE: Retinal ischemia-induced neuronal death plays a crucial role in certain severe visual impairment diseases. The aims of this study were to investigate the effects of low dose cobalt protoporphyrin IX (CoPP), an inducer of heme oxygenase-1 (HO-1), on the retina of rats against ischemia-reperfusion (IR) injury. METHODS: Retinal IR was achieved in rats by raising intraocular pressure for 60 min. CoPP (1 mg/ kg) was injected intraperitoneally 24 hr before IR. Retinal injury was assessed by the number of retinal ganglion cells (RGCs) seven days after reperfusion. TUNEL assay was used to detect the appearance of apoptotic cells 24 hr after reperfusion. The expressions of the HO-1 and Bax proteins were evaluated by Western blot. RESULTS: Both HO-1 expression, examined by Western blot, and enzyme activity were increased strongly after CoPP administration. Rats treated with CoPP before IR had more RGCs (p = 0.034) and less apoptotic cells (p = 0.04) together with downregulated Bax protein levels (p = 0.03) compared to ischemic rats without CoPP. The protective effects of CoPP were HO-1 dependent because the upregulation of HO-1 and the RGC protection were both abolished by the HO-1 inhibitor tin protoporphyrin (SnPP). CONCLUSIONS: In this study, we demonstrated that induction of HO-1 expression by low dose CoPP ameliorated retinal damage from IR injury. The favorable effect appears to be related with modulations of the apoptotic pathway.

Effects of simvastatin on pulmonary C-fiber sensitivity in rats with monocrotaline-induced pulmonary hypertension.

BACKGROUND: The possible mechanisms of simvastatin attenuating pulmonary hypertension (PH) have been widely investigated in pulmonary vascular and hemodynamic systems, but few studies have examined the difference in respiratory response mediated by pulmonary C fibers (PCF) in animal models of PH. We hypothesized that PCF sensitivity would differ from normal in monocrotaline-induced pulmonary hypertension (MCT-PH) rats and the effects of simvastatin treatment would involve not only the pulmonary circulatory system, but also PCF sensitivity. METHODS: The PCF sensitivity was investigated by measuring the apneic durations evoked by 3 chemical stimulants: capsaicin; α,ß-methylene-adenosine triphosphate; and phenylbiguanide. The effects of simvastatin on PCF sensitivity were evaluated in the MCT-PH rat model. RESULTS: The sensitivity of PCF was increased significantly after monocrotaline (MCT) application for 21 days. Bilateral vagatomy and high-dose perivagal capsaicin (250 µg/ml) treatment both blocked the PCF hypersensitivity induced by MCT. Three days of simvastatin (5 mg/kg) treatment significantly reduced the hypersensitive status of PCF. In MCT-PH rats, reactive oxygen species (ROS) production was significantly elevated in both blood and bronchoalveolar lavage, but both showed a significantly decrease after simvastatin treatment. These potential benefits of simvastatin were all abolished by co-application of tin protoporphyrin-IX (SnPP), a specific heme oxygenase-1 (HO-1) inhibitor. CONCLUSION: Simvastatin treatment in MCT-PH rats not only attenuated pulmonary hypertension, but also desensitized PCF hypersensitivity and decreased the production of ROS. These cholesterol-independent effects were mainly through the HO-1 pathway and may all contribute to the therapeutic effects of PH treatment.

Dietary deficiency of vitamin E aggravates retinal ganglion cell death in experimental glaucoma of rats.

PURPOSE: Investigate the effect of dietary vitamin E (Vit E) on the retinas of a rat model of induced glaucoma, in which surgically induced elevation of intraocular pressure (IOP) is associated with an increase in reactive oxygen species. METHODS: Rats were fed a standard chow, Vit E-supplemented diet, or Vit E-deficient diet and subjected to surgically induced IOP elevation (or sham surgery) for five weeks. The retinal ganglion cells (RGCs) were subjected to retrograde fluorescent tracer labeling. RESULTS: The mean number of RGCs of rats on the standard chow, Vit E-supplemented diet, and Vit E-deficient diet were 79.6%, 78.6%, and 71.3% of controls, respectively. Lipid peroxidation of the retinas of rats given a Vit E-deficient diet were significantly higher after IOP elevation for three days (14.42 +/- 0.25 microM, P = 0.016) and five weeks (10.46 +/- 0.11 microM, p = 0.042), compared to rats given standard chow (11.37 +/- 0.31 microM; 8.95 +/- 0.16 microM). Compared with rats given standard chow, rats given a Vit E-deficient diet had significantly elevated concentrations of glutathione (p = 0.032), but no significant differences in the levels of total superoxide dismutase (SOD), Cu/Zn SOD, or catalase activities three days after IOP elevation. CONCLUSIONS: Rats fed a Vit E-deficient diet with surgically induced IOP elevation experience significantly more RGC death than rats fed a normal diet. This phenomenon may be related to the increased level of lipid peroxidation in Vit E-deficient rats.

Effects of epigallocatechin-3-gallate on rat retinal ganglion cells after optic nerve axotomy.

The purpose of this study was to investigate the effects of epigallocatechin-3-gallate (EGCG) in axotomized eyes and the pathways related to its action. Wistar rats received intracranial optic nerve (ON) axotomy 2 mm behind the globe in left eyes, whereas right eyes received sham operations. EGCG was administrated via intraperitoneal injection 30 min before and 4 days after axotomy. The density of retinal ganglion cell (RGC) was examined by a retrograde labeling technique. Western blot analysis was used to assess the expression of neuronal nitric oxide synthase (nNOS), Bax, Bcl-2, ERK and Akt. Optic nerve axotomy caused 54% RGC loss 7 days following surgery, and EGCG treatment reduced RGC loss by 12% (P = 0.017). The expression of the nNOS and pro-apoptotic Bax proteins were increased 5 days after axotomy, while EGCG treatment significantly blunted the up-regulation of the above two proteins (P = 0.04 and 0.02, respectively). Axotomy-induced p-ERK 1/2 and p-Akt proteins expression 5 days and 3 days following injury, respectively. Treatment with EGCG further enhanced p-ERK 1/2 and p-Akt expressions after axotomy. Inhibition of ERK and Akt pathways attenuated the protection of EGCG on RGC against axotomy damage. Thus, we demonstrated that administration of EGCG prior to axotomy promotes RGC survival. The neuroprotective capacity of EGCG appears to act through mediating nitric oxide, anti-apoptotic, and cell survival signaling pathways.

Simvastatin ameliorates established pulmonary hypertension through a heme oxygenase-1 dependent pathway in rats.

BACKGROUND: Simvastatin has been shown to ameliorate pulmonary hypertension by several mechanisms in experimental animal models. In this study, we hypothesized that the major benefits of simvastatin in pulmonary hypertension occur via the heme oxygenase-1 pathway. METHODS: Simvastatin (10 mg/kgw/day) was tested in two rat models of pulmonary hypertension (PH): monocrotaline administration and chronic hypoxia. The hemodynamic changes, right heart hypertrophy, HO-1 protein expression, and heme oxygenase (HO) activity in lungs were measured in both models with and without simvastatin treatment. Tin-protoporphyrin (SnPP, 20 micromol/kg w/day), a potent inhibitor of HO activity, was used to confirm the role of HO-1. RESULTS: Simvastatin significantly ameliorated pulmonary arterial hypertension from 38.0 +/- 2.2 mm Hg to 22.1 +/- 1.9 mm Hg in monocrotaline-induced PH (MCT-PH) and from 33.3 +/- 0.8 mm Hg to 17.5 +/- 2.9 mm Hg in chronic hypoxia-induced PH (CH-PH) rats. The severity of right ventricular hypertrophy was significantly reduced by simvastatin in MCT-PH and CH-PH rats. Co-administration with SnPP abolished the benefits of simvastatin. Simvastatin significantly increased HO-1 protein expression and HO activity in the lungs of rats with PH; however co-administration of SnPP reduced HO-1 activity only. These observations indicate that the simvastatin-induced amelioration of pulmonary hypertension was directly related to the activity of HO-1, rather than its expression. CONCLUSION: This study demonstrated that simvastatin treatment ameliorates established pulmonary hypertension primarily through an HO-1-dependent pathway.

Green tea extract supplement reduces D-galactosamine-induced acute liver injury by inhibition of apoptotic and proinflammatory signaling.

Oxidative stress and inflammation contributed to the propagation of acute liver injury (ALI). The present study was undertaken to determine whether D-galactosamine (D-GalN) induces ALI via the mitochondrial apoptosis- and proinflammatory cytokine-signaling pathways, and possible mechanism(s) by which green tea (GT) extract modulates the apoptotic and proinflammatory signaling in rat. D-GalN induced hepatic hypoxia/hypoperfusion and triggered reactive oxygen species (ROS) production from affected hepatocytes, infiltrated leukocytes, and activated Kupffer cells. D-GalN evoked cytosolic Bax and mitochondrial cytochrome C translocation and activated proinflammatory nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1) translocation, contributing to the increase of intercellular adhesion molecule-1 expression, terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL)-positive hepatocytes, multiple plasma cytokines and chemokines release, and alanine aminotransferase (ALT) activity. An altered biliary secretion profile of several acute phase proteins directly indicates oxidative stress affecting intracellular trafficking in the hepatocyte. GT pretreatment attenuated ROS production, mitochondrial apoptosis- and proinflammatory cytokine-signaling pathway, plasma ALT and cytokines levels, biliary acute phase proteins secretion and hepatic pathology by the enhancement of anti-apoptotic mechanisms. In conclusion, D-GalN induced ALI via hypoxia/hypoperfusion-enhanced mitochondrial apoptosis- and proinflammatory cytokine-signaling pathway, contributing to oxidative stress and inflammation in the liver. GT can counteract the D-GalN-induced ALI via the attenuation of apoptotic and proinflammatory signaling by the upregulation of anti-apoptotic mechanism.

Bevacizumab is not toxic to retinal ganglion cells after repeated intravitreal injection.

PURPOSE: The cytotoxicity of single and repeated administration of bevacizumab to retinal ganglion cells was studied in vivo and in vitro. METHODS: Rats received single or repeated injections of 125 microg of bevacizumab into the vitreous cavity of the left eye, while saline was injected into the right eye as a control. In the repeated injection group, bevacizumab was injected at the same concentration once per week for 4 weeks. Retinal ganglion cells were retrogradely labeled with Fluorogold dye, and counted after kill at 0 and 6 months after treatment. In the in vitro study, PC12 cells were cultured in various concentrations of bevacizumab (0, 1, 2, 5, and 10 mg/mL) to model retinal ganglion cells exposure. Cell viability in each group was assessed by an MTT assay. RESULTS: There was no significant difference in retinal ganglion cell numbers between control and bevacizumab-treated eyes following either single or repeated injection, or did bevacizumab have any significant influence on PC12 cell viability in vitro. CONCLUSION: These results suggest that intravitreal injection of bevacizumab poses no risk to retinal ganglion cells, even after repeated application.

Enhancement of superoxide dismutase activity in rat lungs after hypoxic preconditioning.

Ischemic preconditioning has been proved to reduce tissue damages and benefit subsequent organ transplantation. Chronic hypoxic preconditioning was found to increase the levels of lung antioxidants. This study was to test the hypothesis that levels of lung antioxidants might increase after hypoxia which may counteract the insults of free radicals. Female Wistar rats were kept in an altitude chamber (380 torr) 15 h a day for 4 weeks (hypoxia-adapted). Controls were kept at room air pressure (sea-level). After hypoxic preconditioning, no significant difference in the levels of the oxidative markers, malondialdehyde, thiobarbituric acid reactive substances and isoprostane was seen in the lungs of the hypoxia-adapted rats compared to the sea-level controls. Both the activity and protein level of manganese superoxide dismutase were higher in hypoxia-adapted lungs. Lung manganese superoxide dismutase mRNA levels, determined by real-time RT-PCR, were not significantly different in the two groups of rats. When isolated saline-perfused lungs were prepared and treated with xanthine (500 microM) and xanthine oxidase (5 mU/ml), and the levels of free radicals in the perfusate determined by chemiluminescence, less chemiluminescence was seen in the hypoxia-adapted lung perfusate. When the vascular response was determined in this same preparation before or 45 min after xanthine/xanthine oxidase treatment, the filtration coefficient was increased in the sea-level lungs but not in the hypoxia-adapted lungs. We conclude that an increase in superoxide dismutase activity and protein levels is one of the benefits of hypoxic preconditioning.

Protection of ischemic preconditioning on renal neural function in rats with acute renal failure.

We tested whether tolerance induced by ischemic preconditioning (IPC) in kidneys was related to renal nerves. Experimental acute renal failure (ARF) in a rat model was induced for 45 min of left renal arterial occlusion (RAO), followed by 6 or 24 h of reperfusion (ischemic reperfusion (I/R) group). The episode of IPC was four cycles of 4 min of RAO at 11 min intervals and then the I/R injury was treated as above (IPC-I/R group). After 6 h of reperfusion, polyuria was found in the I/R group associated with an enhancement of afferent renal nerve activity (ARNA) and a reflexive decrease in efferent renal nerve activity (ERNA). Changes in nerve responses were related with a reduction in neutral endopeptidase (NEP) activity and an increased release of substance P (SP). After 24 h of reperfusion, the I/R group showed oliguria which was associated with a lower ARNA, hyperactivity of ERNA and a nine-fold increase in SP release due to a further 52% loss in NEP activity. Prior IPC treatment did not affect the changed ischemia-induced excretory and nervous activity patterns during the first 6 h of reperfusion, but normalized both responses in the kidneys 24 h after ischemia. The IPC-mediated protection in oliguric ARF was related to the preservation of NEP activity to only 25% loss that caused an increase of SP amounts of only three-fold and a minor change in neurokinin 1 receptor (NK-1R) activities. Finally, both excretory and sensory responses in oliguric ARF after saline loading were significantly ameliorated by IPC. We conclude that IPC results in preservation of the renal sensory response in postischemic kidneys and has a beneficial effect on controlling efferent renal sympathetic nerve activity and excretion of solutes and water.

Reduction of hexa(sulfobutyl)fullerence on oxidative injury by xanthine and xanthine oxidase in isolated rat lungs.

UNLABELLED: The present study was undertaken to evaluate whether some fullerenols could effectively reduce direct damages of free radicals produced by xanthine/xanthine oxidase (X/XO) in isolated rat lungs. METHODS: Female Wistar rats (205 +/- 4 g) were used in studies in pulmonary vascular response to the challenge of xanthine/xanthine oxidase by an isolated-perfused lung method. Free radicals were determined by chemiluminescence (CL) to confirm the release of free radicals after X/XO treatment. The CL count in the lung perfusate was 737 +/- 213 (CL/10 sec); 5 min and 45 min after X/XO administration, the CL counts were 3,778 +/- 425 (CL/10 sec) and 1,183 +/- 193 (CL/10 sec), respectively. Challenge with X/XO caused a mild but significant increase in pulmonary arterial pressure (P(pa)) and a marked increase of filtration coefficient (K(fc)). The pretreatment of Hexa (sulfobutyl) fullerence antioxidant, K(fc) became insignificantly increased in pretreated lungs. In conclusion, We found that hexa(sulfobutyl) fullerene, but not Co60(glucosamine)6, nor superoxide dismutase could attenuate the oxidative stress, judged from the attenuated increase in pulmonary filtration coefficient after challenge.

Propofol attenuates the decrease of dynamic compliance and water content in the lung by decreasing oxidative radicals released from the reperfused liver.

BACKGROUND: Remote pulmonary injuries after hepatic reperfusion are frequently caused by reactive oxygen species (ROS)-induced damage. The choice of anesthetics may affect the balance between oxidants and antioxidants, and propofol, a commonly used anesthetic, has an antioxidant effect. In this study, we developed a model to study pulmonary function with hepatic ischemia/reperfusion (I/R) manipulation, with the aim of defining remote pulmonary dysfunction after hepatic reperfusion and determining if propofol affects this dysfunction by altering ROS production from the liver or lungs. METHODS: Adult male rats weighing 160-250 g were randomly divided into four groups according to the type of surgery (sham or I/R) and the anesthetic administered (pentobarbital or propofol). To induce I/R, the portal vein and hepatic artery to the left and medial lobes of the liver were clamped. All of the measurements were done after 5 h of reperfusion, after 45 min of ischemia. Pulmonary function after hepatic I/R was determined by dynamic compliance, resistance and wet-to-dry ratio, and by histopathology. Hepato-cellular injuries were confirmed by alanine aminotransferase, whereas ROS production was measured from the inferior vena cava, jugular vein, and carotid artery. Products of lipid peroxidation, thiobarbiturate acid reactive substances and malondialdehyde, were measured in lung and hepatic tissues. RESULTS: Remote lung injury after hepatic I/R was shown by a significant decrease of Cdyn, and increases in resistance and the wet-to-dry ratio. ROS production was significantly increased and was highest in samples from the inferior vena cava. Thiobarbiturate acid reactive substances and malondialdehyde in the liver and serum alanine aminotransferase were significantly increased only in the I/R+pentobarbital group. All of the changes were significantly attenuated in the I/R+ propofol group (P=0.05). With propofol infusion, there was decreased ROS production from the reperfused liver, with less hepato-cellular injury, followed by well-maintained pulmonary function. CONCLUSION: Remote pulmonary dysfunction and reperfusion injury in the liver were demonstrated in our rat model, as well as massive ROS production and lipid peroxidation. Propofol infusion attenuated remote pulmonary injury by lessening oxidative injury from the reperfused liver.

Haem oxygenase-1 gene transfer protects retinal ganglion cells from ischaemia/reperfusion injury.

RGC (retinal ganglion cell) death following ischaemic insult is the major cause of a number of vision-threatening diseases, including glaucoma. The aim of the present study was to evaluate the role of HO-1 (haem oxygenase-1) in the retina against IR (ischaemia/reperfusion) injury. Adenovirus-mediated HO-1 gene transfer (Adv-HO-1) was carried out by injection into the vitreous body to induce HO-1 overexpression. At 3 weeks after transfection, levels of HO-1 expression, as measured by Western blot analysis, immunohistochemical staining and activity assay, were drastically up-regulated. Transient retinal ischaemia was induced by raising the intraocular pressure to 150 mmHg for 60 min. Untreated IR caused a significant decrease in RGC numbers at 3 and 7 days after reperfusion (76.1 and 67.2% of control eyes with sham IR respectively; P<0.001). Eyes pretreated with Adv-HO-1 had less RGC loss on day 3 and 7 following reperfusion compared with control eyes injected with Adv-GFP (adenovirus containing a gene for green fluorescent protein; 94.3 and 88.2% respectively; P=0.007 and 0.001). SnP (tin protoporphyrin), an HO-1 inhibitor, counteracted the effects of Adv-HO-1. In conclusion, these findings provide evidence that augmentation of HO-1 enzyme overexpression by intravitreal injection is able to protect RGCs against IR-induced damage.

Pharmacological preconditioning with simvastatin protects liver from ischemia-reperfusion injury by heme oxygenase-1 induction.

BACKGROUND: The protective role of heme oxygenase-1 (HO-1) against liver ischemia-reperfusion (I/R) injury in models of hypoxic and remote preconditioning has been proved. The feasible candidates who induce HO-1 and thorough which exert the protective effects are under investigation. The aim was to study the role of HO-1 in pharmacological preconditioning by simvastatin in a rat model. METHODS: Pharmacological preconditioning by intraperitoneal injection of simvastatin (5 mg/kg) was tested on a partial liver I/R model on rats. The expression of HO-1 protein and enzyme activities in livers, serum alanine transaminase (ALT) levels, and TUNEL staining of liver after I/R injury were measured in rats with and without simvastatin preconditioning. RESULTS: HO-1 was induced and persistently overexpressed in the hepatocytes 24 hr after simvastatin treatment. Simvastatin preconditioning diminished the elevation of serum ALT levels 4 hr after I/R injury (69.6+/-26.3 U/L) (P<0.05 vs. other groups) when compared with control (403.8+/-261.9 U/L) and zinc protoporphyrin (ZnPP)-pretreated (717.5+/-205.6 U/L) groups. Simvastatin preconditioning diminished the apoptosis after I/R injury as well (apoptosis index: 26.4+/-8 for Simvastatin, 78+/-7 for control, and 85.3+/-2 for ZnPP group; P<0.05). The addition of ZnPP negated the protective effects of simvastatin as evidenced in the ALT level (406.2+/-243.0 U/L) and apoptosis index (75.6+/-6). The heme oxygenase activity in treated rats correlated with these results. CONCLUSIONS: The induction of HO-1 by simvastatin preconditioning played a protective role against hepatic I/R injury.

NMDA receptor blocker ameliorates ischemia-reperfusion-induced renal dysfunction in rat kidneys.

N-methyl-d-aspartate (NMDA) receptor activated by glutamate/glycine is located in the kidneys. The NMDA receptor subunit NR1 is increased in damaged renal tissue. This study explored the role of NMDA receptors in ischemia-reperfusion-induced renal dysfunction in rats. With Western blot analysis and renal functional assay, NMDA receptor expression was evaluated, as well as its functional role in female Wistar rat kidneys after 45 min of unilateral ischemia followed by 24 h of reperfusion. The effects of intrarenal NMDA receptor agonist and antagonist on renal blood flow (RBF), glomerular filtration rate (GFR), urine volume (UV), sodium (U(Na)V), and potassium (U(K)V) excretion were determined. NMDA NR1 was present in the glomeruli, brush-border membrane, and outer medulla but not in the cortex and inner medulla. Homogenous distribution of non-NMDA GluR2/3, sparse kainate KA1, and undetectable group I of metabotropic glutamate receptor were noted in the control kidneys. Ischemia-reperfusion kidneys showed enhanced renal NR1, but not NR2C and GluR2/3 expression, and were associated with decreased GFR/RBF and natriuretic/diuretic responses. Intrarenal NMDA agonists significantly reduced GFR, UV, U(Na)V, and U(K)V but had no effect on blood pressure and RBF in sham control and ischemia-reperfusion kidneys. NMDA antagonist d-2-amino-5-phosphonopentanoic acid (D-AP-5) treatment completely abolished NMDA-induced renal dysfunction. D-AP-5 treatment significantly ameliorated ischemia-reperfusion-induced glomerular and tubular dysfunction by restoring decreased GFR, UV, and U(Na)V levels. Ischemia-reperfusion upregulates renal NMDA NR1 receptor expression, leading to reduced glomerular and tubular function in the kidneys. The NMDA antagonist can ameliorate ischemia-reperfusion-induced renal dysfunction.

Epigallocatechin-3-gallate reduces retinal ischemia/reperfusion injury by attenuating neuronal nitric oxide synthase expression and activity.

Retinal ischemia/reperfusion (IR) injury causes profound tissue damage, especially retinal ganglion cell death. The aims of the study were twofold: (1) to investigate the benefits of epigallocatechin-3-gallate (EGCG), the major catechin found in tea, after IR challenge, and (2) to elucidate the mechanism of EGCG inhibition of nitric oxide synthase (NOS) expression. Wistar female rats were divided into four groups: normal control, EGCG with sham operation, retinal IR, and EGCG with IR groups. EGCG (50mg/kg) was administered by intraperitoneal injection 30 min before the experiment. IR injury to a rat's retina was induced by raising intraocular pressure to 150 mmHg for 60 min. With EGCG pretreatment, retinal ganglion cell death from IR was reduced by approximately 10% 3 days afterward. EGCG significantly downregulated IR-induced glial fibrillary acidic protein expression. EGCG treatment also reduced TUNEL-positive cells after IR in the inner retina as well as IR-induced lipid peroxidation. Histological analyses showed fewer neuronal NOS and nicotinamide adenine dinucleotide phosphate diaphorase-positive cells in the retina after IR with EGCG administration. Therefore, EGCG is effective in protecting retinal ganglion cells from IR challenge by ameliorating retinal nitrosactive stress and by regulating cell death through apoptotic pathways.