Emodin alleviates intestinal ischemia/reperfusion-induced lung injury by upregulating HO-1 expression via PI3K/AkT pathway.

BACKGROUND: Emodin, a natural anthraquinone derivative found in various Chinese medicinal herbs, has been proved to be an effective therapeutic agent in the treatment of many diseases. However, its effect on lung injury after intestinal ischemia/reperfusion injury remains unknown. This research was designed to investigate whether emodin protects against intestinal ischemia/reperfusion-induced lung injury and to elucidate the underlying molecular mechanisms in vivo and in vitro. METHODS: Intestinal ischemia/reperfusion injury was induced by occluding the superior mesenteric artery in mice, and mouse lung epithelial-12 cells were subjected to oxygen-glucose deprivation and reoxygenation to establish an in vitro model. RESULTS: Our data indicated that emodin treatment reduced intestinal ischemia/reperfusion-induced oxidative stress, inflammation and apoptosis in lung tissues and alleviated lung injury. However, the protective effects of emodin on intestinal ischemia/reperfusion-induced lung injury were reversed by the protein kinase B inhibitor triciribine or the heme oxygenase-1 inhibitor tin protoporphyrin IX. The protein kinase inhibitor triciribine also downregulated the expression of heme oxygenase-1. CONCLUSION: In conclusion, our data suggest that emodin treatment protects against intestinal ischemia/reperfusion-induced lung injury by enhancing heme oxygenase-1 expression via activation of the PI3K/protein kinase pathway. Emodin may act as a potential therapeutic agent for the prevention and treatment of lung injury induced by intestinal ischemia/reperfusion.

ß-caryophyllene, an FDA-Approved Food Additive, Inhibits Methamphetamine-Taking and Methamphetamine-Seeking Behaviors Possibly via CB2 and Non-CB2 Receptor Mechanisms.

Recent research indicates that brain cannabinoid CB2 receptors are involved in drug reward and addiction. However, it is unclear whether ß-caryophyllene (BCP), a natural product with a CB2 receptor agonist profile, has therapeutic effects on methamphetamine (METH) abuse and dependence. In this study, we used animal models of self-administration, electrical brain-stimulation reward (BSR) and in vivo microdialysis to explore the effects of BCP on METH-taking and METH-seeking behavior. We found that systemic administration of BCP dose-dependently inhibited METH self-administration under both fixed-ratio and progressive-ratio reinforcement schedules in rats, indicating that BCP reduces METH reward, METH intake, and incentive motivation to seek and take METH. The attenuating effects of BCP were partially blocked by AM 630, a selective CB2 receptor antagonist. Genetic deletion of CB2 receptors in CB2-knockout (CB2-KO) mice also blocked low dose BCP-induced reduction in METH self-administration, suggesting possible involvement of a CB2 receptor mechanism. However, at high doses, BCP produced a reduction in METH self-administration in CB2-KO mice in a manner similar as in WT mice, suggesting that non-CB2 receptor mechanisms underlie high dose BCP-produced effects. In addition, BCP dose-dependently attenuated METH-enhanced electrical BSR and inhibited METH-primed and cue-induced reinstatement of drug-seeking in rats. In vivo microdialysis assays indicated that BCP alone did not produce a significant reduction in extracellular dopamine (DA) in the nucleus accumbens (NAc), while BCP pretreatment significantly reduced METH-induced increases in extracellular NAc DA in a dose-dependent manner, suggesting a DA-dependent mechanism involved in BCP action. Together, the present findings suggest that BCP might be a promising therapeutic candidate for the treatment of METH use disorder.

Dexmedetomidine Ameliorates Lung Injury Induced by Intestinal Ischemia/Reperfusion by Upregulating Cannabinoid Receptor 2, Followed by the Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway.

Intestinal ischemia/reperfusion (I/R) is a clinical emergency, which often causes lung injury with high morbidity and mortality. Although dexmedetomidine has been identified to have a protective effect on lung injury caused by intestinal I/R, its specific mechanism is still elucidated. In recent years, the cannabinoid (CB2) receptor pathway has been found to be involved in I/R injury of some organs. In the current study, we investigated whether the CB2 receptor pathway contributes to the protective effect of dexmedetomidine on the intestinal I/R-induced lung injury in rats. Dexmedetomidine treatment upregulated the expression of CB2 receptor and suppressed the I/R-induced increases in lung injury scores, inflammatory cell infiltration, lung wet/dry ratio, MPO activity, MDA level, inflammatory cytokines, and caspase-3 expression while augmenting SOD activity and Bcl-2 expression, indicating attenuation of lung injury. Dexmedetomidine treatment also increased the expression of Akt. The protective effects of dexmedetomidine treatment were reversed by the CB2 receptor antagonist AM630 or the PI3K inhibitor wortmannin. And the CB2 receptor antagonist AM630 also downregulated the expression of Akt. Thus, our findings suggest that treatment with dexmedetomidine provides a protective role against lung injury caused by intestinal I/R in rats, possibly due to the upregulation of the CB2 receptor, followed by the activation of the PI3K/Akt pathway.

The HO-1-expressing bone mesenchymal stem cells protects intestine from ischemia and reperfusion injury.

BACKGROUND: Bone mesenchymal stromal cells (BMSC) showed protective potential against intestinal ischemia. Oxygenase-1(HO-1) could alleviate oxidative stress. In the present study, we constructed HO-1-expressing BMSC and detected the effects of it on survival, intestinal injury and inflammation following intestinal ischemia and reperfusion injury (I/R). METHODS: In this experiment, eighty adult male mice were divided into Sham, I/R, I/R + BMSC, I/R + BMSC/HO-1 groups. Mice were anesthetized and intestinal I/R model were established by temporarily occluding the superior mesenteric artery for 60 min with a non-crushing clamp. Following ischemia, the clamp was removed and the intestines were allowed for reperfusion. Prior to abdominal closure, BMSC/ HO-1 (2 × 106 cells) or BMSC (2 × 106 cells) were injected into the peritoneum of I/R mice respectively. Mice were allowed to recover for 24 h and then survival rate, intestinal injury and inflammation were determined. Reactive oxygen species (ROS) was assayed by fluorescent probe. TNFα and IL-6 were assayed by ELISA. RESULTS: BMSC/HO-1 increased seven day survival rate, improved intestinal injury and down-regulated inflammation after intestinal I/R when compared with sole BMSC (p < 0.05 respectively). Multiple pro-inflammatory media were also decreased following application of BMSC/HO-1, when compared with sole BMSC (p < 0.05) respectively, suggesting that BMSC /HO-1 had a better protection to intestinal I/R than BMSC therapy. CONCLUSION: Administration of BMSC/HO-1 following intestinal I/R, significantly improved intestinal I/R by limiting intestinal damage and inflammation.

Cannabinoid CB1 receptor neutral antagonist AM4113 inhibits heroin self-administration without depressive side effects in rats.

Cannabinoid CB1 receptors (CB1Rs) have been shown to be a promising target in medication development for the treatment of addiction. However, clinical trials with SR141716A (rimonabant, a selective CB1R antagonist/inverse agonist) for the treatment of obesity and smoking cessation failed due to unwanted side effects, such as depression, anxiety, and suicidal tendencies. Recent preclinical studies suggest that the neutral CB1R antagonist AM4113 may retain the therapeutic anti-addictive effects of SR141716A in nicotine self-administration models and possibly has fewer unwanted side effects. However, little is known about whether AM4113 is also effective for other drugs of abuse, such as opioids and psychostimulants, and whether it produces depressive side effects similar to SR141716A in experimental animals. In this study, we demonstrated that systemic administration of AM4113 (3 and 10 mg/kg) dose-dependently inhibited the self-administration of intravenous heroin but not cocaine or methamphetamine, whereas SR141716A (3 and 10 mg/kg) dose-dependently inhibited the self-administration of heroin and methamphetamine but not cocaine. In the electrical brain-stimulation reward (BSR) paradigm, SR141716A (3 and 10 mg/kg) dose-dependently increased the BSR stimulation threshold (i.e., decreased the stimulation reward), but AM4113 had no effect on BSR at the same doses, suggesting that SR141716A may produce aversive effects while AM4113 may not. Together, these findings show that neutral CB1R antagonists such as AM4113 deserve further research as a new class of CB1R-based medications for the treatment of opioid addiction without SR141716A-like aversive effects.

SP1, MYC, CTNNB1, CREB1, JUN genes as potential therapy targets for neuropathic pain of brain.

Neuropathic pain (NP) may cause serious brain diseases, but the genes associated with the metabolic pathway and transcript factors of NP remain unclear. This study is aimed to identify the therapy target genes for NP and to investigate the metabolic pathways and transcript factors associated with NP. The differentially expressed genes of three brain tissues (nucleus accumbens, periaqueductal gray, and prefrontal cortex) dealt with NP stimulation were analyzed. Besides, The Database for Annotation, Visualization, and Integrated Discovery and Tfacts datasets were used in the analysis of the genes related to the metabolic pathway and transcript factors of the brain. Eight genes were found to coexpress in all three tissues. A functional enrichment analysis showed that the upregulated genes were mostly enriched in pathways as inflammatory response, calcium-mediated signaling, cytokine-cytokine receptor interaction, and extracellular matrix (ECM)-receptor interaction, whereas the downregulated genes were mostly enriched in pathways as phospholipid metabolic processes, positive regulation of protein kinase B signaling, and metabolism of xenobiotics by cytochrome P450. Finally, 135 and 98 transcript factors genes were upregulated and downregulated, among which SP1, MYC, CTNNB1, CREB1, JUN were identified as the most critical genes because the number of up- and downregulated gene ranked at the top. In conclusion, the pathways of immune response and cytokine-cytokine receptor interaction were determined as the main metabolic pathways of NP affecting the brain, and SP1, MYC, CTNNB1, CREB1, JUN genes were recognized as the most enriched genes in this process, which may provide evidence for the diagnosis and treatment research of neuropathic pain.

Genetic deletion of the dopamine D3 receptor increases vulnerability to heroin in mice.

Despite extensive research, the neurobiological risk factors that convey vulnerability to opioid abuse are still unknown. Recent studies suggest that the dopamine D3 receptor (D3R) is involved in opioid self-administration, but it remains unclear whether altered D3R availability is a risk factor for the development of opioid abuse and addiction. Here we used dopamine D3 receptor-knockout (D3-KO) mice to investigate the role of this receptor in the different phases of opioid addiction. D3-KO mice learned to self-administer heroin faster and took more heroin than wild-type mice during acquisition and maintenance of self-administration. D3R-KO mice also displayed higher motivation to work to obtain heroin reward during self-administration under progressive-ratio reinforcement, as well as elevated heroin-seeking during extinction and reinstatement testing. In addition, deletion of the D3R induced higher baseline levels of extracellular dopamine (DA) in the nucleus accumbens (NAc), higher basal levels of locomotion, and reduced NAc DA and locomotor responses to lower doses of heroin. These findings suggest that the D3R is critically involved in regulatory processes that normally limit opioid intake via DA-related mechanisms. Deletion of D3R augments opioid-taking and opioid-seeking behaviors. Therefore, low D3R availability in the brain may represent a risk factor for the development of opioid abuse and addiction.

Transduced PEP-1-Heme Oxygenase-1 Fusion Protein Attenuates Lung Injury in Septic Shock Rats.

Oxidative stress and inflammation have been identified to play a vital role in the pathogenesis of lung injury induced by septic shock. Heme oxygenase-1 (HO-1), an effective antioxidant and anti-inflammatory and antiapoptotic substance, has been used for the treatment of heart, lung, and liver diseases. Thus, we postulated that administration of exogenous HO-1 protein transduced by cell-penetrating peptide PEP-1 has a protective role against septic shock-induced lung injury. Septic shock produced by cecal ligation and puncture caused severe lung damage, manifested in the increase in the lung wet/dry ratio, oxidative stress, inflammation, and apoptosis. However, these changes were reversed by treatment with the PEP-1-HO-1 fusion protein, whereas lung injury in septic shock rats was alleviated. Furthermore, the septic shock upregulated the expression of Toll-like receptor 4 (TLR4) and transcription factor NF-κB, accompanied by the increase of lung injury. Administration of PEP-1-HO-1 fusion protein reversed septic shock-induced lung injury by downregulating the expression of TLR4 and NF-κB. Our study indicates that treatment with HO-1 protein transduced by PEP-1 confers protection against septic shock-induced lung injury by its antioxidant, anti-inflammatory, and antiapoptotic effects.

XIST accelerates neuropathic pain progression through regulation of miR-150 and ZEB1 in CCI rat models.

LncRNAs are reported to participate in neuropathic pain development. LncRNA X-inactive specific transcript (XIST) is involved in the progression of various cancers. However, the role of XIST in neuropathic pain remains unclear. In our present study, we established a chronic constriction injury (CCI) rat model and XIST was found to be greatly upregulated both in the spinal cord tissues and in the isolated microglias of CCI rats. Inhibition of XIST inhibited neuropathic pain behaviors including mechanical and thermal hyperalgesia. Moreover, decrease of XIST repressed neuroinflammation through inhibiting COX-2, tumor necrosis factor (TNF)-α and IL-6 and in CCI rats. Previously, miR-150 has been reported to restrain neuropathic pain by targeting TLR5. Currently, miR-150 was predicted to be a microRNA target of XIST, which indicated a negative correlation between miR-150 and XIST. miR-150 was remarkably decreased in CCI rats and overexpression of miR-150 can significantly suppress neuroinflammation-related cytokines. Furthermore, ZEB1 was exhibited to be a direct target of miR-150 and we found it was overexpressed in CCI rats. Silencing ZEB1 was able to inhibit neuropathic pain in vivo and downreguation of XIST decreased ZEB1, which can be reversed by miR-150 inhibitors. Taken these together, we indicated that XIST can induce neuropathic pain development in CCI rats via upregulating ZEB1 by acting as a sponge of miR-150. It was revealed that XIST/miR-150/ZEB1 axis can be provided as a therapeutic target in neuropathic pain.

Inhibition of miR-200b/miR-429 contributes to neuropathic pain development through targeting zinc finger E box binding protein-1.

Many studies have reported that microRNAs participate in neuropathic pain development. Previously, miR-200b and miR-429 are reported to be involved in various diseases. In our current study, we focused on their roles in neuropathic pain and we found that miR-200b and miR-429 were significantly decreased in chronic constriction injury (CCI) rat spinal cords and isolated microglials. miR-200b and miR-429 overexpression were able to relieve neuropathic pain through modulating PWT and PWL in CCI rats. Meanwhile, we observed that both miR-200b and miR-429 upregulation could repress neuroinflammation via inhibiting inflammatory cytokines such as IL-6, IL-1ß, and TNF-α in CCI rats. By carry out bioinformatics technology, Zinc finger E box binding protein-1 (ZEB1) was predicted as target of miR-200b, and miR-429 and dual-luciferase reporter assays confirmed the correlation between them. ZEB1 has been reported to regulate a lot of diseases. Here, we found that ZEB1 was greatly increased in CCI rats and miR-200b and miR-429 overexpression markedly suppressed ZEB1 mRNA expression in rat microglial cells. In addition, knockdown of ZEB1 can reduce neuropathic pain development and co-transfection of LV-anti-miR-200b/miR-429 reversed this phenomenon in vivo. Taken these together, our results suggested that miR-200b/miR-429 can serve as an important regulator of neuropathic pain development by targeting ZEB1.

EFFECT OF INTRAPERITONEAL RESUSCITATION WITH DIFFERENT CONCENTRATIONS OF SODIUM PYRUVATE ON INTESTINAL ISCHEMIA REPERFUSION INJURY IN HEMORRHAGIC SHOCK RAT.

OBJECTIVE: To determine the effects of intraperitoneal resuscitation (PR) with different concentrations of sodium pyruvate (PY) on intestinal ischemia reperfusion injury in rats hemorrhagic shock (HS). METHODS: Sixty rats were randomly assigned to six groups. These included: group SHAM, intravenous resuscitation only (VR) group, and four PR groups based on resuscitation fluid: glucose-lactate-based peritoneal dialysis solution (LA), and PY-1.1%, PY-1.6%, and PY-2.2% (concentrations in grams/dL). Mean arterial pressure (MAP) was monitored continuously. Blood pH, base excess (BE), lactate, intestinal myeloperoxidase (MPO), malondialdehyde (MDA), tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), activated caspase-3, and zonula occludens-1 (ZO-1) were measured; intestinal mucosal damage index (IMDI) and subcellular changes were observed; apoptotic index (AI) was calculated. RESULTS: Three hours after resuscitation, in PY groups, MPO, MDA, IMDI, AI, TNF-alpha, and IL-6 were significantly lower than VR and LA groups, while pH and BE were higher. PY groups showed less expression of activated caspase-3 but elevated ZO-1. Among PY groups, group PY-1.1% had the lowest MPO, MDA and TNF-alpha, and had less pathological damage and subcellular changes than other experimental groups. CONCLUSIONS: PR using PY solution combined with VR provided protection against intestinal ischemia-reperfusion injury following HS and resuscitation. Under the same hypertonic condition, 1.1% PY solution showed significant advantages compared with 2.2% and 1.6% solutions. The underlying mechanisms may include the maintenance of hemodynamic stability, regulation of homeostasis, inhibition of oxidative stress and inflammation, and protection of intestinal epithelial tight junction barrier function.

Transduced PEP-1-heme oxygenase-1 fusion protein reduces remote organ injury induced by intestinal ischemia/reperfusion.

BACKGROUND: A fusion protein composed of heme oxygenase-1 (HO-1) and cell-penetrating peptide PEP-1 has been shown to reduce local intestinal injury after intestinal ischemia/reperfusion (I/R). In this study, we investigated the effects of PEP-1-HO-1 fusion protein on remote organ injury induced by intestinal I/R in rats. MATERIAL AND METHODS: We randomly assigned 24 male Sprague-Dawley rats to 3 groups: Sham, I/R, and I/R plus PEP-1-HO-1 treatment (HO). The model of intestinal I/R was established by occluding the superior mesenteric artery for 45 min followed by 120-min reperfusion. In HO group, PEP-1-HO-1 was administered intravenously 30 min before ischemia, while animals in the Sham and I/R groups received the equal volume of physiological saline. At the end of the experiment, lung, liver, and blood samples were collected and analyzed. RESULTS: Malondialdehyde levels and histological injury scores were increased, and superoxide dismutase activities were decreased in the lung and liver tissues in the I/R group compared with the Sham group (P<0.05). Serum levels of alanine aminotransferase, aspartate aminotransferase, tumor necrosis factor-α, interleukin-6, and lung tissue wet weight to dry weight ratio were increased in the I/R group compared with the Sham group (P<0.05). NF-κB expression in intestinal tissues was significantly higher in the I/R group than in the Sham group. These changes were significantly reversed by treatment with PEP-1-HO-1. CONCLUSIONS: This study demonstrates that administration of PEP-1-HO-1 has a protective role against lung and liver injury after intestinal I/R, attributable to the reduction of released proinflammatory cytokines regulated by NF-κB.

Protection against intestinal injury from hemorrhagic shock by direct peritoneal resuscitation with pyruvate in rats.

OBJECTIVE: We explored the effects of direct peritoneal resuscitation with pyruvate-peritoneal dialysis solution (PDS) following intravenous resuscitation (VR) on intestinal ischemia-reperfusion injury in rats with hemorrhagic shock (HS). METHODS: Fifty rats were randomly assigned equally to five groups. In group sham, a surgical operation was performed on rats without shock or resuscitation. In group VR, rats were subjected only to VR. In groups NS, LA, and PY, direct peritoneal resuscitation was performed with normal saline (NS), lactate-based PDS (Lac-PDS), and pyruvate-based PDS (Pyr-PDS), respectively, after VR. Mean arterial pressure was monitored in the right common carotid artery. Two hours after resuscitation, the lactate level in arterial blood and the wet weight/dry weight ratio of the intestine were determined. The intestinal mucosal damage index was estimated, and ultrastructural changes in the intestinal mucosa were observed. Malondialdehyde, myeloperoxidase, nitric oxide, and tumor necrosis factor α levels were also measured. RESULTS: Two hours after HS and resuscitation, the increase in arterial blood lactate and intestinal wet weight/dry weight ratio declined significantly in rats from Groups LA and PY compared with groups VR and NS, whereas group PY was more advantageous in the changes of these parameters. The intestinal mucosal damage index and ultrastructural changes were also improved in groups LA and PY when compared with groups VR and NS. Protection was more apparent with Pyr-PDS than Lac-PDS. Hemorrhagic shock resulted in a significant increase in malondialdehyde levels and myeloperoxidase activity and was accompanied by overexpression of tumor necrosis factor α and a reduction in nitric oxide levels. These changes were significantly attenuated by Lac-PDS and Pyr-PDS at 2 h after resuscitation, and Pyr-PDS showed more effective protection for the intestine than Lac-PDS. CONCLUSIONS: Direct peritoneal resuscitation with Lac-PDS and Pyr-PDS after VR alleviated intestinal injury from HS in rats, and Pyr-PDS was superior to Lac-PDS in its protective effect. Mechanisms of action might include the elimination of free oxygen radicals, reduction of neutrophil infiltration, inhibition of the inflammatory response, and regulation of intestinal mucosal blood flow and barrier function.

Transduced PEP-1-heme oxygenase-1 fusion protein protects against intestinal ischemia/reperfusion injury.

BACKGROUND: Heme oxygenase-1 (HO-1) has been shown to have antioxidant and anti-apoptotic properties. The present study transduced HO-1 protein into intestinal tissues using PEP-1, a cell-penetrating peptide, and investigated its potentiality in prevention against intestinal ischemia/reperfusion (I/R) injury. MATERIALS AND METHODS: PEP-1-HO-1 fusion protein was administered intravenously to explore the time and dose characteristics through measuring serum HO-1 levels. Twenty-four male Sprague-Dawley rats were randomly divided into three groups: sham, intestinal I/R (II/R), II/R + PEP-1-HO-1 fusion protein (HO). The model was established by occluding the superior mesenteric artery for 45 min followed by 120 min reperfusion. In HO group, PEP-1-HO-1 was administered intravenously 30 min before ischemia, whereas animals in sham and II/R groups received the equal volume of physiological saline. After the experiment, the intestines were harvested for determination of histologic injury, wet/dry ratio, enzyme activity, apoptosis, and His-probe protein (one part of PEP-1-HO-1). RESULTS: Levels of serum HO-1 were dose- and time-dependent manner after intravenous injection of PEP-1-HO-1. I/R caused deterioration of histologic characteristics and increases in histologic injury scoring, wet/dry ratio, myeloperoxidase activity, malondialdehyde, and intestinal apoptosis. These changes were also accompanied by a decrease in superoxide dismutase activity (P < 0.05). PEP-1-HO-1 treatment significantly reversed these changes (P < 0.05). Furthermore, His-probe protein expression was only detected in PEP-1-HO-1-treated animals. CONCLUSION: Treatment of PEP-1-HO-1 attenuates intestinal I/R injury, which might be attributable to its antioxidant and anti-apoptotic roles of HO-1.

Transduction of PEP-1-heme oxygenase-1 fusion protein reduces myocardial ischemia/reperfusion injury in rats.

Recent studies have uncovered that overexpression of heme oxygenase-1 (HO-1) by induction or gene transfer provides myocardial protection. In the present study, we investigated whether HO-1 protein mediated by cell-penetrating peptide PEP-1 could confer cardioprotection in a rat model of myocardial ischemia/reperfusion (I/R) injury. Male Sprague-Dawley rats were subjected to 30 minutes of ischemia by occluding the left anterior descending coronary artery and to 120 minutes of reperfusion to prepare the model of I/R. Animals were randomized to receive PEP-1-HO-1 fusion protein or saline 30 minutes before a 30-minute occlusion. I/R increased myocardial infarct size and levels of malondialdehyde, serum tumor necrosis factor alpha, and interleukin 6 and reduced myocardial superoxide dismutase activity. Administration of PEP-1-HO-1 reduced myocardial infarct size and levels of malondialdehyde, serum tumor necrosis factor alpha, and interleukin 6 and increased myocardial superoxide dismutase and HO-1 activities. His-probe protein was only detected in PEP-1-HO-1-transduced hearts. In addition, transduction of PEP-1-HO-1 markedly reduced elevated myocardial tissue nuclear factor-κB induced by I/R. The results suggested that transduction of PEP-1-HO-1 fusion protein decreased myocardial reperfusion injury, probably by attenuating the production of oxidants and proinflammatory cytokines regulated by nuclear factor-κB.

Honokiol protects rat hearts against myocardial ischemia reperfusion injury by reducing oxidative stress and inflammation.

Honokiol, a potent radical scavenger, has been demonstrated to ameliorate cerebral infarction following ischemia/reperfusion (I/R) injury. However, its effects on myocardial I/R injury remain unclear. The present study aimed to examine the effects of honokiol on myocardial I/R injury and to investigate its potential cardioprotective mechanisms. Sprague-Dawley rats were pretreated with honokiol and exposed to a 30-min myocardial ischemia followed by 2-h coronary reperfusion. Myocardial I/R-induced infarct size and biochemical and histological changes were compared. The expression of nuclear factor κB(NF-κB; p65) was assessed by western blotting. Pretreatment with honokiol significantly reduced infarct size, and serum creatine kinase (CK) and lactate dehydrogenase (LDH) release compared with those in the I/R group following a 2-h reperfusion. The malondialdehyde (MDA) level, myeloperoxidase (MPO) activity, concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-6 and expression level of NF-κB were all reduced by honokiol pretreatment, while honokiol inhibited the decreases in superoxide dismutase (SOD) and catalase (CAT) activities. In addition, less neutrophil infiltration and histopathological damage in the myocardium were observed in the honokiol-pretreated group. These findings indicate that honokiol pretreatment diminished myocardial I/R injury through attenuation of oxidative stress and inflammation.

Protective effect of PNU-120596, a selective alpha7 nicotinic acetylcholine receptor-positive allosteric modulator, on myocardial ischemia-reperfusion injury in rats.

The cholinergic anti-inflammatory pathway has been found to exert a protective role in myocardial ischemia-reperfusion injury (MIRI). Alpha7 nicotinic acetylcholine receptor (α7nAChR) is a regulator of cholinergic anti-inflammatory pathway; however, little information is available on the effect of α7nAChR on MIRI. In the present study, we hypothesized that 1-(5-chloro-2,4-dimethoxy-phenyl)-3-(5-methyl-isoxanol-3-yl)-urea (PNU-120596), a potent positive allosteric modulator of α7nAChR, could play a protective role on MIRI. Fifty-five rats were randomly assigned into 4 groups: Sham group, ischemia-reperfusion group, PNU-120596 group, α-bungarotoxin group. Compared with ischemia-reperfusion group, PNU-120596 treatment markedly decreased infarct size, ultrastructural damage, serum creatine kinase, and lactate dehydrogenase. Serum proinflammatory cytokine production, myocardium endothelial activation and neutrophil infiltration, myocardium malondialdehyde were also significantly decreased, accompanied by increased myocardium superoxide dismutase production, in the PNU-120596 group compared with the ischemia-reperfusion group. Meanwhile, we observed a significant inhibition of nuclear factor kappa B activation in PNU-120596 group compared with ischemia-reperfusion group. Pretreatment of α7nAChR-selective antagonist, α-bungarotoxin, abolished all the protective effects of PNU-120596 on MIRI. In conclusion, PNU might have a protective effect against MIRI. Its action mechanisms might be involved in the inhibition of inflammatory responses, attenuation of lipid peroxidation, and suppression of nuclear factor kappa B activity.

[Effects of transfection of rat heme oxygenase-1 on cardiomyocyte apoptosis induced by myocardial ischemia/ reperfusion injury in rats].

OBJECTIVE: To investigate the effect of rat heme oxygenase-1 (rHO-1) gene carried by recombinant adeno-associated virus (rAAV) on myocardial ischemia/reperfusion (I/R) injury in rats. METHODS: Ninety-five healthy male Sprague-Dawley (SD) rats weighing 225-250 g were randomly divided into four groups: sham operation group (I, n=8); normal saline group (II, n=29); rAAV-EGFP (enhanced green fluorescent protein) group (III, n=29) and rAAV-rHO-1 group (IV, n=29). In II, III and IV groups, 600 mul of normal saline, rAAV-EGFP or rAAV-rHO-1 was injected intra-myocardial at four sites on the anterior and posterior walls of left ventricle. After 3 months, 3 animals in each group were sacrificed. EGFP-expression in heart sections was observed under fluorescence microscope. The expression of HO-1 in the injected myocardium was detected by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The remaining animals in the four groups were anesthetized, tracheostomized and mechanically ventilated. I/R of myocardium was producing by blocking the left anterior descending branch of coronary artery (LAD) for 30 minutes followed by 120 minutes reperfusion. After the successful reproduction of the model, the animals were killed and their hearts were harvested for determination of myocardial infarct size, apoptotic index (AI), and pathology changes in myocardial tissue. RESULTS: The expression of EGFP was detected in group III only, and transfection efficiency was (53.5+/-2.0)%. AI was significantly higher in group II, group III and group IV than in group I (all P<0.01). The expression of HO-1 mRNA and protein was significantly higher, and the infarct size and AI were significantly lower in group IV than in group II and group III (all P<0.01). The degree of damage to myocardial tissue was significantly severer in group II and group III than in group I and group IV. There was no significant difference between group II and group III. CONCLUSION: rAAV-mediated rHO-1 gene transfection may attenuate myocardium I/R injury by inhibiting apoptosis of cardiomyocyte in rats.

Urinary trypsin inhibitor treatment ameliorates acute lung and liver injury resulting from sepsis in a rat model.

OBJECTIVE: To evaluate the protective effect of urinary trypsin inhibitor (UTI) on acute lung and liver injury in rat model induced by sepsis with infra-abdominal infection. METHODS: This study was performed in the University of Wuhan, Wuhan, China in May 2007. Sepsis models were made by cecal ligation and puncture (CLP) in Sprague-Dawley rats. Forty rats were randomly divided into sham, CLP, CLP/UTI I (20 u/g) and CLP/UTI II (50 u/g) groups, with 10 rats in each. All of them were sacrificed 12 hours after CLP. The mean arterial pressure (MAP), heart rate (HR), the wet-to-dry lung weight ratio (W/D) was measured and venous blood was collected for assaying tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactic acid. Superoxide dismutase (SOD), malondialdehyde (MDA) and expression of inducible nitric oxide synthase (iNOS) mRNA in lung and hepatic tissues were examined. RESULTS: Compared with the CLP group, MAP and HR in 50 u/g UTI treated rats was stable (p<0.01). Marked elevation levels of W/D ratio were lowered after administration of 50 u/g UTI (p<0.01). Treatment with 50 u/g UTI prevented marked elevation in MDA, ALT, AST, TNF-alpha, lactic acid levels, expression of iNOS mRNA, and elevated IL-10 and SOD activity (p<0.01). CONCLUSION: Urinary trypsin inhibitor has a protective effect against sepsis. Its action mechanisms are probably involved in the inhibition of inflammatory factor production and suppression of lipid peroxidation and iNOS mRNA expression.