The protective effects of sildenafil in acute lung injury in a rat model of severe scald burn: A biochemical and histopathological study

Lung Protection After Severe Thermal Burns With Adenosine, Lidocaine, and Magnesium (ALM) Resuscitation and Importance of Shams in a Rat Model

The management of severe burns remains a complex challenge. Adenosine, lidocaine, and magnesium (ALM) resuscitation therapy has been shown to protect against hemorrhagic shock and traumatic injury. The aim of the present study was to investigate the early protective effects of small-volume ALM fluid resuscitation in a rat model of 30% total body surface area (TBSA) thermal injury. Male Sprague-Dawley rats (320-340 g; n = 25) were randomly assigned to: 1) Sham (surgical instrumentation and saline infusion, without burn, n = 5), 2) Saline resuscitation group (n = 10), or 3) ALM resuscitation group (n = 10). Treatments were initiated 15-min after burn trauma, including 0.7 mL/kg 3% NaCl ± ALM bolus and 0.25-0.5 mL/kg/h 0.9% NaCl ± ALM drip, with animals monitored to 8.25-hr post-burn. Hemodynamics, cardiac function, blood chemistry, hematology, endothelial injury markers and histopathology were assessed. Survival was 100% for Shams and 90% for both ALM and Saline groups. Shams underwent significant physiological, immune and hematological changes over time as a result of surgical traums. ALM significantly reduced malondialdehyde levels in the lungs compared to Saline (P = .023), and showed minimal alveolar destruction and inflammatory cell infiltration (P < .001). ALM also improved cardiac function and oxygen delivery (21%, P = .418 vs Saline), reduced gut injury (P < .001 vs Saline), and increased plasma adiponectin (P < .001 vs baseline). Circulating levels of the acute phase protein alpha 1-acid glycoprotein (AGP) increased 1.6-times (P < .001), which may have impacted ALM's therapeutic efficacy. We conclude that small-volume ALM therapy significantly reduced lung oxidative stress and preserved alveolar integrity following severe burn trauma. Further studies are required to assess higher ALM doses with longer monitoring periods.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

Potential protective effect of 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) against bleomycin-induced lung injury in male albino rat via modulation of Nrf2 pathway: biochemical, histological, and immunohistochemical study

Acute lung injury is a serious condition accounting for the majority of acute respiratory failure. Bleomycin (BLM) is an antibiotic that was first described as a chemotherapeutic agent. 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) was reported to have anti-inflammatory, anti-apoptotic, and anti-oxidative properties. The current work aimed to assess the possible protective effects and the mechanism of protection of 3,3'-methylenebis-(1-ethyl-4-hydroxyquinolin-2(1H)-one) on BLM-induced lung injury in addition to the effect and underlying mechanisms of nuclear factor-erythroid-related factor 2 pathway against this injury. Rats were equally divided into four groups: control group, BLM group, 1-ethyl-4-hydroxyquinolin-2(1H)-one-treated group, and BLM with 1-ethyl-4-hydroxyquinolin-2(1H)-one-treated group. At the end of the work, the blood samples were proceeded for biochemical study. Lung specimens were obtained for biochemical, histological, and immunohistochemical study. The results exhibited a significant increase in both malondialdehyde and tumor necrotic factor-α with a significant decrease in glutathione, superoxide dismutase, IL 10, surfactant protein A, and nuclear factor erythroid 2-related factor 2 in BLM group. The lung histological results showed various morphological changes in the form of disturbed architecture, inflammatory cell infiltration, and intraluminal debris. This group also displayed a significant increase in the mean surface area fraction of anti-cleaved caspase 3, while group IV exhibited amelioration in the previously mentioned parameters and histological alternations that were induced by BLM. It could be concluded that 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) has anti-oxidative, anti-inflammatory, and anti-apoptotic protective effects against BLM-induced lung injury.

Porcine Fibrin Sealant Promotes Skin Wound Healing in Rats

Objective

Fibrin sealant (FS) is widely used for skin wound healing, but data on porcine FS (PFS), a new type of FS, are limited. This study investigated the effects and potential mechanisms of porcine fibrin sealant (PFS) on skin wound healing in rats. Methods. Traumatic rats were randomly divided into three groups: control, PFS, and medical Vaseline. The wound area and wound index of the rats were measured within 14 days after surgery. Hematoxylin-eosin (H&E) staining and Masson staining were used to observe the pathological images and collagen formation on the wounded skin, respectively. To investigate the healing mechanisms, the enzyme-linked immunosorbent assay (ELISA) was used to detect platelet endothelial cell adhesion molecule-1 (CD31) and cluster of differentiation 34 (CD34) expression in the wounded skin. Additionally, quantitative real-time PCR (qRT-PCR) was used to evaluate the mRNA levels of the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and epidermal growth factor (EGF), and transforming growth factor-β1 (TGF-β1). Meanwhile, TGF-β1 protein expression was assessed by Western blot analysis.

Results

Compared with the control group, both PFS and medical Vaseline treatment significantly reduced the wounded area and increased the wound closure rate. H&E staining showed that the cells in the PFS group proliferated rapidly, and the epidermis and dermis were thickened to some extent with a clear epidermal cell structure. Moreover, PFS promoted the formation of collagen and significantly increased the levels of CD31 and CD34 and the growth factors in the skin tissues of the traumatic rats.

Conclusion

PFS effectively promoted skin wound healing, especially in tissue formation, reepithelialization, angiogenesis, and collagen deposition, in traumatic rat models. This study provides a new strategy and scientific foundation for PFS application in skin wound healing.

The Effect of Udenafil on Stasis Zone in an Experimental Burn Model

BACKGROUND

Management of the burn injuries is still a problematic issue because the stasis zone may become necrotic. We hypothesized that udenafil, a potent phospodiesterase inhibitor, can be beneficial in burn treatment by enhancing the viability of the stasis zone.

METHODS

Fifteen Wistar rats were randomly divided into 3 groups. Comb burn injury model was conducted bilaterally on the back of rats in each subject. Group 1 received 1 mL/d of saline orally for 7 days. Group 2 received 10 mg/kg per day of udenafil for 7 days. Group 3 received 20 mg/kg per day of udenafil for 7 days. At the end of seventh day, gross morphological and histopathological samples of stasis zone survival were evaluated.

RESULTS

Histopathological examination of groups 2 and 3 revealed that the stasis zone was mostly viable. The mean necrotic area and severity of inflammation was significantly higher in the control group compared with the treatment groups. Significant differences were determined in treatment groups compared with control group in terms of vital stasis zone area and histopathological parameters.

CONCLUSIONS

Udenafil treatment improved tissue survival on zone of stasis in. Future experimental studies should be conducted to develop zone of stasis treatment protocols combining udenafil with potent anti-inflammatory and antioxidant drugs.

Burn Ointment Promotes Cutaneous Wound Healing by Modulating the PI3K/AKT/mTOR Signaling Pathway

Burn ointment (BO) is a clinically useful medicine for the treatment of burns and scalds. However, there is no enough scientific evidence to report the effect of BO on wound healing and its analgesic and anti-inflammatory efficacy. The aim of this work was to evaluate the anti-inflammatory and analgesic efficacy of BO and to reveal the potential wound healing properties and related mechanisms of BO. In this work, the content of active ingredients of BO was determined by high-performance liquid chromatography (HPLC). Two animal models of inflammation were used to study its anti-inflammatory activity, and a hot plate method was used to evaluate its analgesic effect. In addition, mouse incision and rat burn models were used to investigate the effect of BO on the anti-inflammatory and wound healing mechanisms. The results showed that BO was safe for topical application, and BO could significantly inhibit auricular swelling in mice and paw swelling in rats and significantly prolong the latency period of paw licking in the hot plate experiment in mice. It can also accelerate wound healing and repair scars by promoting the formation of new epithelial tissues in rat burn models. In addition, BO significantly downregulated the serum level of TNF-α and significantly increased the serum levels of VEGF and TGF-β1. Also, BO promoted the expression of collagen I and increased the ratio in p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR pathways. Our results demonstrate the safety and efficacy of BO and suggest that activation of the PI3K/AKT/mTOR signaling pathway may play an important role in the promotion of wound healing by BO.

Phosphodiesterase Inhibitors in Acute Lung Injury: What Are the Perspectives?

Despite progress in understanding the pathophysiology of acute lung damage, currently approved treatment possibilities are limited to lung-protective ventilation, prone positioning, and supportive interventions. Various pharmacological approaches have also been tested, with neuromuscular blockers and corticosteroids considered as the most promising. However, inhibitors of phosphodiesterases (PDEs) also exert a broad spectrum of favorable effects potentially beneficial in acute lung damage. This article reviews pharmacological action and therapeutical potential of nonselective and selective PDE inhibitors and summarizes the results from available studies focused on the use of PDE inhibitors in animal models and clinical studies, including their adverse effects. The data suggest that xanthines as representatives of nonselective PDE inhibitors may reduce acute lung damage, and decrease mortality and length of hospital stay. Various (selective) PDE3, PDE4, and PDE5 inhibitors have also demonstrated stabilization of the pulmonary epithelial-endothelial barrier and reduction the sepsis- and inflammation-increased microvascular permeability, and suppression of the production of inflammatory mediators, which finally resulted in improved oxygenation and ventilatory parameters. However, the current lack of sufficient clinical evidence limits their recommendation for a broader use. A separate chapter focuses on involvement of cyclic adenosine monophosphate (cAMP) and PDE-related changes in its metabolism in association with coronavirus disease 2019 (COVID-19). The chapter illuminates perspectives of the use of PDE inhibitors as an add-on treatment based on actual experimental and clinical trials with preliminary data suggesting their potential benefit.

Sildenafil beyond erectile dysfunction and pulmonary arterial hypertension: Thinking about new indications

Sildenafil, approved two decades ago, is the inhibitor of phosphodiesterase 5 (PDE5). First of all, it was designated for angina pectoris, but soon it showed a wonderful efficacy in erectile dysfunction (ED) and then pulmonary arterial hypertension (PAH). Due to the distribution of phosphodiesterase (PDE) in almost all organs, maybe it effects other diseases. Hence, a great number of investigations began to understand the role of PDEi in different organs. Preliminary research on sildenafil in cell culture and animal models has yielded promising results. Soon, a greater number of animal researches and clinical trials joined them. The results disclosed sildenafil can have beneficial effects in each organ such as heart, liver, kidney, brain, and intestines. Furthermore, it has significantly improved the prognosis of organ ischemia in various animal models. Clinical trials in several diseases, such as recurrent spontaneous miscarriage, fatty liver disease, bronchopulmonary dysplasia (BPD), heart failure, and premature ejaculation (PE) brought promising results. Although some clinical trials are available on the effects of sildenafil on various diseases, further studies on humans are needed to consolidate the ultimate effects of sildenafil. The aim of this review was to describe the effects of sildenafil on each organ and explain its mechanisms of action. Further, other PDE inhibitors such as tadalafil and vardenafil have been briefly discussed in parts of this review.

Repurposing existing drugs for COVID-19: an endocrinology perspective

BACKGROUND

Coronavirus Disease 2019 (COVID-19) is a multi-systemic infection caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), that has become a pandemic. Although its prevailing symptoms include anosmia, ageusia, dry couch, fever, shortness of brief, arthralgia, myalgia, and fatigue, regional and methodological assessments vary, leading to heterogeneous clinical descriptions of COVID-19. Aging, uncontrolled diabetes, hypertension, obesity, and exposure to androgens have been correlated with worse prognosis in COVID-19. Abnormalities in the renin-angiotensin-aldosterone system (RAAS), angiotensin-converting enzyme-2 (ACE2) and the androgen-driven transmembrane serine protease 2 (TMPRSS2) have been elicited as key modulators of SARS-CoV-2.

MAIN TEXT

While safe and effective therapies for COVID-19 lack, the current moment of pandemic urges for therapeutic options. Existing drugs should be preferred over novel ones for clinical testing due to four inherent characteristics: 1. Well-established long-term safety profile, known risks and contraindications; 2. More accurate predictions of clinical effects; 3. Familiarity of clinical management; and 4. Affordable costs for public health systems. In the context of the key modulators of SARS-CoV-2 infectivity, endocrine targets have become central as candidates for COVID-19. The only endocrine or endocrine-related drug class with already existing emerging evidence for COVID-19 is the glucocorticoids, particularly for the use of dexamethasone for severely affected patients. Other drugs that are more likely to present clinical effects despite the lack of specific evidence for COVID-19 include anti-androgens (spironolactone, eplerenone, finasteride and dutasteride), statins, N-acetyl cysteine (NAC), ACE inhibitors (ACEi), angiotensin receptor blockers (ARB), and direct TMPRSS-2 inhibitors (nafamostat and camostat). Several other candidates show less consistent plausibility. In common, except for dexamethasone, all candidates have no evidence for COVID-19, and clinical trials are needed.

CONCLUSION

While dexamethasone may reduce mortality in severely ill patients with COVID-19, in the absence of evidence of any specific drug for mild-to-moderate COVID-19, researchers should consider testing existing drugs due to their favorable safety, familiarity, and cost profile. However, except for dexamethasone in severe COVID-19, drug treatments for COVID-19 patients must be restricted to clinical research studies until efficacy has been extensively proven, with favorable outcomes in terms of reduction in hospitalization, mechanical ventilation, and death.

Burn-Induced Cardiac Mitochondrial Dysfunction via Interruption of the PDE5A-cGMP-PKG Pathway

Burn-induced heart dysfunction is a key factor for patient mortality. However, the molecular mechanisms are not yet fully elucidated. This study sought to understand whether burn-induced heart dysfunction is associated with cardiac mitochondrial dysfunction and interruption of the PDE5A-cGMP-PKG pathway. Sixty percent total body surface area (TBSA) scald burned rats (±sildenafil) were used in this study. A transmission electron microscope (TEM), real-time qPCR, O2K-respirometer, and electron transport chain assays were used to characterized molecular function. Cardiac mitochondrial morphological shapes were disfigured with a decline in mitochondrial number, area, and size, resulting in deficiency of cardiac mitochondrial replication. Burn induced a decrease in all mitDNA encoded genes. State 3 oxygen consumption was significantly decreased. Mitochondrial complex I substrate-energized or complex II substrate-energized and both of respiratory control ratio (RCRs) were decreased after burn. All mitochondrial complex activity except complex II were decreased in the burn group, correlating with decreases in mitochondrial ATP and MnSOD activity. Sildenafil, a inhibitor of the PDE5A-cGMP-PKG pathway, preserved the mitochondrial structure, respiratory chain efficiency and energy status in cardiac tissue. Furthermore, sildenafil treatment significantly restored ADP-conjugated respiration in burned groups. In conclusion, cardiac mitochondrial damage contributes to burn-induced heart dysfunction via the PDE5A-cGMP-PKG pathway.

Mesenchymal stem cells alleviate hydrochloric acid-induced lung injury through suppression of inflammation, oxidative stress and apoptosis in comparison to moxifloxacin and sildenafil

Introduction

Acute lung injury (ALI) is a severe life-threatening disease causing uncontrolled pulmonary inflammation and oxidative damage. There are still no effective therapies for this disease. The aim of this study was to evaluate the protective role of mesenchymal stem cells, moxifloxacin, sildenafil or a combination of moxifloxacin and sildenafil against hydrochloric Acid (HCl) - induced ALI.

Methods

HCl or saline was injected intra-tracheally and after 2 h, moxifloxacin, sildenafil, moxifloxacin + sildenafil or mesenchymal stem cells were injected. After 7 days, rats were sacrificed for evaluation of the blood chemistry and inflammation via determination of the level of oxidative stress markers, apoptosis and the histopathological alterations by H&E.

Results

In HCl-injected rats, there were a significant increase in total white blood cells (WBCs), lymphocytes, malondialdehyde (MDA) and caspase-3 gene expression. Also, there were a significant decrease in superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and Hemeoxygenase-1 (HO-1) gene expression in lung tissue. On the other hand, treatment of lung injured rats with mesenchymal stem cell, moxifloxacin, sildenafil or a combination of moxifloxacin and sildenafil showed a significant decrease in WBCs and lymphocytes and ameliorated the histopathological changes. MDA level in lung tissue was only significantly lowered in rats treated with moxifloxacin alone or in combination with sildenafil or MSCs. GSH was just increased in rats treated with moxifloxacin, sildenafil or with MSCs. Antioxidant parameters and gene expression of HO-1 and caspase-3 were significantly modulated in rats treated with MSCs.

Conclusion

MSCs ameliorated the toxic effects of HCl through their ability to decrease inflammation, oxidative stress, and apoptosis in acute lung injury.

Inhibitory effects of sildenafil and tadalafil on inflammation, oxidative stress and nitrosative stress in animal model of bronchial asthma

BACKGROUND

Cyclic neucleotides are involved in many cellular functions including smooth muscle relaxation, inflammation, and signal transduction. Sildenafil and tadalafil are phosphodiesterase-5 (PDE-5) inhibitors which prevent the degradation of cyclic neucleotide i.e. guanosine 3',5' cyclic monophosphate (cGMP) and increase the levels of cGMP. In this study sildenafil and tadalafil were evaluated for their anti-inflammatory, anti-oxidative and anti-nitrosative stress potential in animal model of bronchial asthma.

METHODS

Wistar rats were sensitized with 10 mg intraperitoneal (ip) ovalbumin adsorbed to 10 μg of aluminum hydroxide on day 0. Animals were given sildenafil (1 and 3 mg/kg ip) and tadalafil (1 and 3 mg/kg ip) from day 1 to day 14. Also, on day 14 animals were challenged with ovalbumin (1 mg ip). After 24 h, samples were collected to analyze interleukin-4 (IL-4) and tumour necrosis factor-α (TNF-α), in serum and bronchoalveolar lavage fluid (BALF). The oxidative stress markers malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide metabolites (NO_x) were also measured in serum.

RESULTS

Pre-treatment with sildenafil (1 and 3 mg/kg ip) and tadalafil (1 and 3 mg/kg ip) significantly reduced the levels of pro-inflammatory cytokines IL-4 and TNF-α in rat serum and BALF. In addition, pre-treatment with both the drugs decreased the levels of MDA and NO_x and increased the levels of GSH in serum.

CONCLUSIONS

Sildenafil and tadalafil decreased pro-inflammatory cytokines in serum and BALF. Both drugs inhibit oxidative and nitrosative stress in animal model of bronchial asthma and could have a therapeutic potential in bronchial asthma.

N-Acetylcysteine potentiates the haemodynamic-improving effect of sildenafil in a rabbit model of acute pulmonary thromboembolism via the p38 MAPK pathway

The current study aimed to investigate the effects of sildenafil and N-acetylcysteine (NAC) on the haemodynamics in a rabbit model of acute pulmonary thromboembolism (APT). We developed an APT model using healthy male China big-ear rabbits (2.7 ± 0.4 kg). The rabbits were divided into five groups subjected to various interventions. We recorded the haemodynamic parameters and assessed the oxidative stress and lipid peroxidation response in the groups. Additionally, we detected apoptosis-associated molecules, FoxO1, Bad and Bcl-2, in the lung tissue. Gelatine zymography was used to detect matrix metalloproteinase (MMP) activity in bronchoalveolar lavage (BLA). Pulmonary artery endothelial cells were isolated, and their apoptosis rates and MMP activity were assayed. N-acetylcysteine potentiated the haemodynamic-improving effect of sildenafil and significantly inhibited the oxidative stress response. N-acetylcysteine combined with sildenafil decreased MMP-2 and MMP-9 activity and NO consumption and inhibited apoptosis of pulmonary arterial endothelial cells. Moreover, NAC combined with sildenafil inhibited the expression of MCP-1 and p-p38 MAPK. Thus, NAC potentiates the haemodynamic-improving effect of sildenafil in a rabbit model of acute pulmonary thromboembolism via the MCP-1 and p38 MAPK signalling pathway. This study may provide a promising treatment method for APT.

Burn-Induced Multiple Organ Injury and Protective Effect of Lutein in Rats

Thermal injury may lead to multiple organ dysfunction through release of proinflammatory mediators and reactive oxygen radicals. This study investigated the effects of thermal injury on remote organs of rats and the possible protective effect of lutein. Thermal trauma was induced in the back of rats by exposing them to 90 °C bath for 10 s. Rats were sacrificed 48 h after burn, and blood samples were collected to monitor liver and kidney functions. Tissue samples from liver, kidneys, and lungs were taken for studying oxidative stress parameters, gene expressions of TNF-α and Casp-3, besides histopathological examination. Skin scald injury caused significant elevations of liver and kidney function biomarkers in the serum. In tissue samples, increments of MDA, GPx, and 8-OHdG were recorded while GSH level and the activities of CAT and SOD were suppressed. The expressions of TNF-α and caspase-3 mRNA were increased, and histopathological results revealed remote organ injury. Oral administration of lutein (250 mg/kg) resulted in amelioration of the biochemical and molecular changes induced by burn as well as the histopathological alterations. According to the findings of the present study, lutein possesses anti-oxidant, anti-inflammatory, and anti-apoptotic effects that protect against burn-induced damage in remote organs.

Carvacrol attenuates cyclophosphamide-induced oxidative stress in rat kidney

Cyclophosphamide (CP) is an antineoplastic drug that induces kidney damage via producing oxidative stress. Carvacrol (CAR) has antioxidative effect and we postulated that it can be protective against CP-induced nephrotoxicity. Six groups (n = 7) of rats (control, 100 mg/kg CP, CP+5 mg/kg CAR, CP+10 mg/kg CAR, 5 mg/kg CAR, and 10 mg/kg CAR) were injected intraperitoneally. Serum malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), creatinine (CRE), total antioxidant capacity (TAC), and total oxidant state (TOS) were measured, and oxidative stress indexes (OSI) were calculated. Kidneys were also analyzed histologically. In CP-alone group MDA, CRE, TOS, and OSI levels increased whereas GSH, SOD, CAT, and TAC levels decreased compared with control group. In CP plus CAR groups, MDA, TOS, and OSI levels decreased whereas GSH, SOD, CAT, and TAC levels increased compared with CP-alone group. However, CRE levels were similar in CP-alone and CP+5 CAR group whereas decreased in CP+10 CAR group. CP+10 CAR group was significantly different in all parameters (except TAC) from CP+5 CAR group. Kidney microscopy was showed lower tissue damage in CP plus CAR groups. In conclusion, 10 mg/kg CAR is more effective than 5 mg/kg CAR in prevention of CP-induced oxidative damage on kidney.

The effect of electroacupuncture at ST36 on severe thermal injury-induced remote acute lung injury in rats

OBJECTIVE

Acupuncture at ST36 can produce anti-inflammatory effects, which might be associated with vagus nerve activity. This study explored the effects of electroacupuncture (EA) at ST36 on severe thermal injury-induced remote acute lung injury in rats.

INTERVENTIONS

Forty male Sprague-Dawley (SD) rats were randomly divided into five groups: (1) the sham (S) group, (2) the thermal injury (TEM) group subjected to 30% total body surface area (30% TBSA) third-degree scald, (3) the EA at ST36 group subjected to EA stimulation at ST36 (3V, 2ms, and 3Hz) after 30% TBSA scald, (4) the EA at non-acupoint group subjected to EA stimulation at non-acupoint after 30% TBSA scald, and (5) the α-bungarotoxin (α7 nicotinic acetylcholine receptor subunit antagonist) group administered 1.0 μg kg(-1) α-bungarotoxin before EA at ST36.

MEASUREMENTS AND MAIN RESULTS

Thermal injury of 30% TBSA induced leukocytosis in the alveolar space, interstitial edema, and the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and high-mobility group box 1 (HMGB-1); the expression of both HMGB-1 messenger RNA (mRNA) and protein in lung tissue was significantly enhanced. EA at ST36 significantly downregulated the levels of inflammatory cytokines and improved lung tissue injury. However, pretreatment with α-bungarotoxin reversed the effects of electrical stimulation of ST36.

CONCLUSIONS

EA at ST36 might have a potential protective effect on severe thermal injury-induced remote acute lung injury via limitation of inflammatory responses in rats.

Animal models in burn research

Burn injury is a severe form of trauma affecting more than 2 million people in North America each year. Burn trauma is not a single pathophysiological event but a devastating injury that causes structural and functional deficits in numerous organ systems. Due to its complexity and the involvement of multiple organs, in vitro experiments cannot capture this complexity nor address the pathophysiology. In the past two decades, a number of burn animal models have been developed to replicate the various aspects of burn injury, to elucidate the pathophysiology, and to explore potential treatment interventions. Understanding the advantages and limitations of these animal models is essential for the design and development of treatments that are clinically relevant to humans. This review aims to highlight the common animal models of burn injury in order to provide investigators with a better understanding of the benefits and limitations of these models for translational applications. While many animal models of burn exist, we limit our discussion to the skin healing of mouse, rat, and pig. Additionally, we briefly explain hypermetabolic characteristics of burn injury and the animal model utilized to study this phenomena. Finally, we discuss the economic costs associated with each of these models in order to guide decisions of choosing the appropriate animal model for burn research.

Mesenchymal stromal cell injection protects against oxidative stress in Escherichia coli-induced acute lung injury in mice

BACKGROUND AIMS

Stem cells may be a promising therapy for acute respiratory distress syndrome. Recent in vivo and in vitro studies suggested that the mesenchymal stromal cells (MSCs) have anti-oxidative stress properties. We hypothesized that intravenous injection of bone marrow-derived mesenchymal stem cells (MSCs) could attenuate Escherichia coli-induced acute lung injury (ALI) in mice by controlling the oxidative stress status.

METHODS

Eighty mice were randomly divided into four groups: group 1 (control group) received 25 μL of saline as a vehicle; group 2 contained E coli-induced ALI mice; group 3 included mice that received MSCs before induction of ALI; group 4 included mice that received MSCs after induction of ALI. Lung samples were isolated and assayed for oxidative stress variables and histopathologic analysis. Total anti-oxidant capacity was measured in broncho-alveolar lavage.

RESULTS

Pre- and post-injury MSC injection increased survival, reduced pulmonary edema and attenuated lung injuries in ALI mice. Histologically, MSCs exhibited a considerable degree of preservation of the pulmonary alveolar architecture. An increase of anti-oxidant enzyme activities and a decrease of myeloperoxidase activity and malondialdehyde levels in the MSC recipient groups versus the ALI group were found. Furthermore, the total anti-oxidant capacity and reduced glutathione levels were significantly increased in MSCs recipient groups versus the ALI group. Weak +ve inducible nitric oxide synthase immuno-expression in groups that received MSCs was detected. Pre-injury MSC injection showed better effects than did post-injury MSC injection.

CONCLUSIONS

Systemic bone marrow-derived MSC injection was effective in modulating the oxidative stress status in E coli-induced acute lung injury in mice.