Desflurane Attenuates Ventilator-Induced Lung Injury in Rats with Acute Respiratory Distress Syndrome

Desflurane alleviates LPS-induced acute lung injury by modulating let-7b-5p/HOXA9 axis

Acute lung injury (ALI) is characterized by acute respiratory failure with tachypnea and widespread alveolar infiltrates, badly affecting patients' health. Desflurane (Des) is effective against lung injury. However, its mechanism in ALI remains unknown. BEAS-2B cells were incubated with lipopolysaccharide (LPS) to construct an ALI cell model. Cell apoptosis was evaluated using flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was employed to examine the levels of inflammatory cytokines. Interactions among let-7b-5p, homeobox A9 (HOXA9), and suppressor of cytokine signaling 2 (SOCS2) were verified using Dual luciferase activity, chromatin immunoprecipitation (ChIP), and RNA pull-down analysis. All experimental data of this study were derived from three repeated experiments. Des treatment improved LPS-induced cell viability, reduced inflammatory cytokine (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6)) levels, decreased cell apoptosis, down-regulated the pro-apoptotic proteins (Bcl-2-associated X protein (Bax) and cleaved caspase 3) expression, and up-regulated the anti-apoptotic protein B-cell-lymphoma-2 (Bcl-2) expression in LPS-induced BEAS-2B cells. Des treatment down-regulated let-7b-5p expression in LPS-induced BEAS-2B cells. Moreover, let-7b-5p inhibition improved LPS-induced cell injury. let-7b-5p overexpression weakened the protective effects of Des. Mechanically, let-7b-5p could negatively modulate HOXA9 expression. Furthermore, HOXA9 inhibited the NF-κB signaling by enhancing SOCS2 transcription. HOXA9 overexpression weakened the promotion of let-7b-5p mimics in LPS-induced cell injury. Des alleviated LPS-induced ALI via regulating let-7b-5p/ HOXA9/NF-κB axis.

Naringin-Dextrin Nanocomposite Abates Diethylnitrosamine/Acetylaminofluorene-Induced Lung Carcinogenesis by Modulating Oxidative Stress, Inflammation, Apoptosis, and Cell Proliferation

Nanotechnology has proven advantageous in numerous scientific applications, one being to enhance the delivery of chemotherapeutic agents. This present study aims to evaluate the mechanisms underlying the chemopreventive action of naringin-dextrin nanocomposites (Nar-Dx-NCs) against diethylnitrosamine (DEN)/2-acetylaminofluorene (2AAF)-induced lung carcinogenesis in male Wistar rats. DEN was administered intraperitoneally (i.p.) (150 mg/kg/week) for two weeks, followed by the oral administration of 2AAF (20 mg/kg) four times a week for three weeks. Rats receiving DEN/2AAF were concurrently treated with naringin or Nar-Dx-NCs orally at a dose of 10 mg/kg every other day for 24 weeks. Naringin and Nar-Dx-NCs treatments prevented the formation of tumorigenic cells within the alveoli of rats exposed to DEN/2AAF. These findings were associated with a significant decrease in lipid peroxidation, upregulation of antioxidant enzyme (glutathione peroxidase and superoxide dismutase) activity, and enhanced glutathione and nuclear factor erythroid 2-related factor 2 expression in the lungs. Naringin and Nar-Dx-NCs exerted anti-inflammatory actions manifested by a decrease in lung protein expression of tumor necrosis factor-α and interleukin-1β and mRNA expression of interleukin-6, interferon-γ, nuclear factor-κB, and inducible nitric oxide synthase, with a concurrent increase in interleukin-10 expression. The anti-inflammatory effect of Nar-Dx-NCs was more potent than naringin. Regarding the effect on apoptosis, both naringin and Nar-Dx-NCs significantly reduced Bcl-2 and increased Bax and P53 expressions. Moreover, naringin or Nar-Dx-NCs induced a significant decrease in the expression of the proliferator marker, Ki-67, and the effect of Nar-Dx-NCs was more marked. In conclusion, Nar-Dx-NCs improved naringin's preventive action against DEN/2AAF-induced lung cancer and exerted anticarcinogenic effects by suppressing oxidative stress and inflammation and improving apoptotic signal induction and propagation.

Sedation and Anesthesia in Exotic Animal Critical Care

Sedation and anesthesia of exotic animals in inherently challenging, but often facilitates the best care for patients. Critical illness or injury adds on another layer of complexity to their management for obtaining diagnostics and providing treatments. This article serves to review some of the more recent literature of sedation and anesthesia within exotics practice, bringing to light some nuances and considerations for when those patients are critically ill or injured.

Saroglitazar, a dual PPAR-α/γ agonist, alleviates LPS-induced hepatic and renal injury in rats

BACKGROUND

Lipopolysaccharide (LPS), an endotoxin within gram-negative bacteria, is associated with systemic acute inflammatory response after invading living tissues and results in sepsis. The liver and kidney are both major target organs in sepsis. Septic acute hepatic-renal injury is a serious clinical condition with high risk of morbidity and mortality. Nevertheless, effective treatment is still lacking.

AIM

This study highlights saroglitazar (SAR), a dual PPAR-α/γ agonist, as a proposed prophylactic drug against LPS-induced hepatic-renal injury.

MAIN METHODS

Rats were pretreated with SAR (2 and 4 mg/kg/day) for 15 days, while sepsis was induced by LPS injection (10 mg/kg) on day 15 one hour following SAR oral administration.

KEY FINDINGS

SAR pretreatment could successfully mitigate LPS-induced hepatic-renal injury, evidenced by enhancement of renal and hepatic functions and a decrease of tissue pathological injury. Meanwhile, SAR alleviated LPS-induced oxidative stress; it reduced malondialdehyde (MDA) levels and ameliorated decreased levels of superoxide dismutase (SOD) and glutathione (GSH). LPS-induced elevations in hepatic and renal nuclear factor-kappa B (NF-κB), phosphorylated inhibitor of kappa B alpha (p-IκBα), interferon-beta (IFN-β), and hepatic high mobility group box-1 (HMGB-1) contents were significantly attenuated in SAR-treated groups. SAR showed an advantageous impact against LPS-induced activation of non-canonical inflammasome and pyroptosis via a significant reduction in cysteinyl aspartate-specific proteinase-11 (Caspase-11) and gasdermin D (GSDMD) expressions. Moreover, Nucleotide-Binding Oligomerization Domain (NOD)-Like Receptor Protein 3 (NLRP3) inflammasome activation with concomitant expression and activation of caspase-1 and release of interleukin-1beta (IL-1β) were considerably diminished following SAR pretreatment.

SIGNIFICANCE

SAR could be considered a prophylactic anti-inflammatory antioxidant drug against LPS-induced liver and kidney injury.

The GABA and GABA-Receptor System in Inflammation, Anti-Tumor Immune Responses, and COVID-19

GABA and GABA_A-receptors (GABA_A-Rs) play major roles in neurodevelopment and neurotransmission in the central nervous system (CNS). There has been a growing appreciation that GABA_A-Rs are also present on most immune cells. Studies in the fields of autoimmune disease, cancer, parasitology, and virology have observed that GABA-R ligands have anti-inflammatory actions on T cells and antigen-presenting cells (APCs), while also enhancing regulatory T cell (Treg) responses and shifting APCs toward anti-inflammatory phenotypes. These actions have enabled GABA_A-R ligands to ameliorate autoimmune diseases, such as type 1 diabetes (T1D), multiple sclerosis (MS), and rheumatoid arthritis, as well as type 2 diabetes (T2D)-associated inflammation in preclinical models. Conversely, antagonism of GABA_A-R activity promotes the pro-inflammatory responses of T cells and APCs, enhancing anti-tumor responses and reducing tumor burden in models of solid tumors. Lung epithelial cells also express GABA-Rs, whose activation helps maintain fluid homeostasis and promote recovery from injury. The ability of GABA_A-R agonists to limit both excessive immune responses and lung epithelial cell injury may underlie recent findings that GABA_A-R agonists reduce the severity of disease in mice infected with highly lethal coronaviruses (SARS-CoV-2 and MHV-1). These observations suggest that GABA_A-R agonists may provide off-the-shelf therapies for COVID-19 caused by new SARS-CoV-2 variants, as well as novel beta-coronaviruses, which evade vaccine-induced immune responses and antiviral medications. We review these findings and further advance the notions that (1) immune cells possess GABA_A-Rs to limit inflammation in the CNS, and (2) this natural "braking system" on inflammatory responses may be pharmacologically engaged to slow the progression of autoimmune diseases, reduce the severity of COVID-19, and perhaps limit neuroinflammation associated with long COVID.

A GABA-receptor agonist reduces pneumonitis severity, viral load, and death rate in SARS-CoV-2-infected mice

Gamma-aminobutyric acid (GABA) and GABA-receptors (GABA-Rs) form a major neurotransmitter system in the brain. GABA-Rs are also expressed by 1) cells of the innate and adaptive immune system and act to inhibit their inflammatory activities, and 2) lung epithelial cells and GABA-R agonists/potentiators have been observed to limit acute lung injuries. These biological properties suggest that GABA-R agonists may have potential for treating COVID-19. We previously reported that GABA-R agonist treatments protected mice from severe disease induced by infection with a lethal mouse coronavirus (MHV-1). Because MHV-1 targets different cellular receptors and is biologically distinct from SARS-CoV-2, we sought to test GABA therapy in K18-hACE2 mice which develop severe pneumonitis with high lethality following SARS-CoV-2 infection. We observed that GABA treatment initiated immediately after SARS-CoV-2 infection, or 2 days later near the peak of lung viral load, reduced pneumonitis severity and death rates in K18-hACE2 mice. GABA-treated mice had reduced lung viral loads and displayed shifts in their serum cytokine/chemokine levels that are associated with better outcomes in COVID-19 patients. Thus, GABA-R activation had multiple effects that are also desirable for the treatment of COVID-19. The protective effects of GABA against two very different beta coronaviruses (SARS-CoV-2 and MHV-1) suggest that it may provide a generalizable off-the-shelf therapy to help treat diseases induced by new SARS-CoV-2 variants and novel coronaviruses that evade immune responses and antiviral medications. GABA is inexpensive, safe for human use, and stable at room temperature, making it an attractive candidate for testing in clinical trials. We also discuss the potential of GABA-R agonists for limiting COVID-19-associated neuroinflammation.

Effect and Mechanism Study of Sodium Houttuyfonate on Ventilator-Induced Lung Injury by Inhibiting ROS and Inflammation

PURPOSE

Ventilator-induced lung injury (VILI) is a serious complication of mechanical ventilation (MV) that increases morbidity and mortality of patients receiving ventilator treatment. This study aimed to reveal the molecular mechanism of sodium houttuyfonate (SH) on VILI.

MATERIALS AND METHODS

The male mice VILI model was established by high tidal volume ventilation. The cell model was established by performing cell stretch (CS) experiments on murine respiratory epithelial cells MLE-15. In addition, the JNK activator Anisomycin and JNK inhibitor SP600125 were used on VILI mice and CS-treated cells.

RESULTS

VILI modeling damaged the structural integrity, increased apoptosis and wet-to-dry (W/D) ratio, enhanced the levels of inflammatory factors, reactive oxygen species (ROS) and malonaldehyde (MDA), and activated JNK pathway in lung tissues. SH gavage alleviated lung injury, decreased apoptosis and W/D ratio, and reduced levels of inflammatory factors, ROS and MDA, and p-JNK/JNK expression of lung tissues in VILI mice. However, activation of JNK wiped the protective effect of SH on VILI. Contrary results were found in experiments with JNK inhibitor SP600125.

CONCLUSION

SH relieved VILI by inhibiting the ROS-mediated JNK pathway.

GABAA-Receptor Agonists Limit Pneumonitis and Death in Murine Coronavirus-Infected Mice

There is an urgent need for new approaches to limit the severity of coronavirus infections. Many cells of the immune system express receptors for the neurotransmitter γ-aminobutyric acid (GABA), and GABA-receptor (GABA-R) agonists have anti-inflammatory effects. Lung epithelial cells also express GABA-Rs, and GABA-R modulators have been shown to limit acute lung injuries. There is currently, however, no information on whether GABA-R agonists might impact the course of a viral infection. Here, we assessed whether clinically applicable GABA-R agonists could be repurposed for the treatment of a lethal coronavirus (murine hepatitis virus 1, MHV-1) infection in mice. We found that oral GABA administration before, or after the appearance of symptoms, very effectively limited MHV-1-induced pneumonitis, severe illness, and death. GABA treatment also reduced viral load in the lungs, suggesting that GABA-Rs may provide a new druggable target to limit coronavirus replication. Treatment with the GABA_A-R-specific agonist homotaurine, but not the GABA_B-R-specific agonist baclofen, significantly reduced the severity of pneumonitis and death rates in MHV-1-infected mice, indicating that the therapeutic effects were mediated primarily through GABA_A-Rs. Since GABA and homotaurine are safe for human consumption, they are promising candidates to help treat coronavirus infections.

Sufentanil attenuates inflammation and oxidative stress in sepsis-induced acute lung injury by downregulating KNG1 expression

The present study aimed to investigate the effects of sufentanil on sepsis-induced acute lung injury (ALI), and identify the potential molecular mechanisms underlying its effect. In order to achieve this, a rat sepsis model was established. Following treatment with sufentanil, the lung wet/dry (W/D) weight ratio was calculated. Histopathological analysis was performed via hematoxylin and eosin staining. Levels of inflammatory factors in bronchoalveolar lavage fluid were determined via ELISA. Furthermore, malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in tissue homogenates were assessed using commercial kits. Western blot analysis was performed to determine kininogen-1 (KNG1) protein expression. In addition, alveolar epithelial type II cells (AEC II) were stimulated with lipopolysaccharide (LPS) to mimic ALI. The levels of inflammation and oxidative stress were evaluated following overexpression of KNG1. Protein expression levels of nuclear factor-κB (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling were determined via western blot analysis. The results of the present study demonstrated that sufentanil alleviated histopathological injury and the W/D ratio in lung tissue. Following treatment with sufentanil, levels of inflammatory factors also decreased, accompanied by decreased concentrations of MDA, and increased activities of SOD, CAT and GSH-Px. Notably, KNG1 was decreased in lung tissues following treatment with sufentanil. Furthermore, overexpression of KNG1 attenuated the inhibitory effects of sufentanil on LPS-induced inflammation and oxidative stress in AEC II. Sufentanil markedly downregulated NF-κB expression, while upregulating Nrf2 and HO-1 expression levels, which was reversed following overexpression of KNG1. Taken together, the results of the present study suggested that sufentanil may alleviate inflammation and oxidative stress in sepsis-induced ALI by downregulating KNG1 expression.

Anticancer Effect of Rosiglitazone, a PPAR-γ Agonist against Diethylnitrosamine-Induced Lung Carcinogenesis

Multiple effects on cancer cells are exerted by the peroxisome proliferator-activated receptor γ (PPAR-γ). Recent studies have shown that rosiglitazone, a synthetic PPAR-γ ligand, inhibits the growth of cells. This research was designed to assess the impact of rosiglitazone on diethylnitrosamine (DENA)-induced lung carcinogenesis in Wistar rats and to study the underlying molecular mechanism. A total of 40 adult male Wistar rats were separated into four groups as follows: group 1 is known as a control. Group 2 is known as the DENA group (150 mg/kg, i.p.). Group 3 and group 4 denote DENA-induced rats treated with 5 and 10 mg/kg rosiglitazone, respectively. Lipid peroxidation, various antioxidant enzymes, histological perceptions, and caspase-3, Bcl2, and Bax gene expression were measured in lung tissues. Rosiglitazone treatment reverted the DENA-induced changes in the expression of these genes, inflammatory cytokines, and oxidative stress. However, blotting analysis discovered reduced caspase-3 and BAX expressions and elevated Bcl-2 expression in DENA-induced rats. The expression of such proteins causing DENA lung cancer was restored by rosiglitazone therapy.

Postoperative remote lung injury and its impact on surgical outcome

Postoperative remote lung injury is a complication following various surgeries and is associated with short and long-term mortality and morbidity. The release of proinflammatory cytokines, damage-associated molecular patterns such as high-mobility group box-1, nucleotide-biding oligomerization domain (NOD)-like receptor protein 3 and heat shock protein, and cell death signalling activation, trigger a systemic inflammatory response, which ultimately results in organ injury including lung injury. Except high financial burden, the outcome of patients developing postoperative remote lung injury is often not optimistic. Several risk factors had been classified to predict the occurrence of postoperative remote lung injury, while lung protective ventilation and other strategies may confer protective effect against it. Understanding the pathophysiology of this process will facilitate the design of novel therapeutic strategies and promote better outcomes of surgical patients. This review discusses the cause and pathology underlying postoperative remote lung injury. Risk factors, surgical outcomes and potential preventative/treatment strategies against postoperative remote lung injury are also addressed.