The effect of captopril on lipopolysaccharide-induced lung inflammation

Captopril attenuates oxidative stress and neuroinflammation implicated in cisplatin-induced cognitive deficits in rats

RATIONALE

One of the most debilitating drawbacks of cisplatin chemotherapy is neurotoxicity which elicits memory impairment and cognitive dysfunction (chemobrain). This is primarily triggered by oxidative stress and inflammation. Captopril, an angiotensin-converting enzyme inhibitor, has been reported as a neuroprotective agent owing to its antioxidant and anti-inflammatory effects.

OBJECTIVE

We examined the possible neuroprotective effect of captopril against cisplatin-induced neurological and behavioral abnormalities in rats.

METHODS

Chemobrain was induced in rats by cisplatin (5 mg/kg, i.p.) on the 7th and 14th days of the study while captopril was administered orally (25 mg/kg) daily for three weeks. The effects of captopril were assessed by performing behavioral tests, histological examination, and evaluation of oxidative stress and inflammatory markers.

RESULTS

Cisplatin caused learning/memory dysfunction assessed by passive avoidance and Y-maze tests, decline in locomotion, and rotarod motor balance loss which were further verified by neurodegeneration observed in histological examination. Also, cisplatin aggravated oxidative stress by elevating lipid peroxidation (MDA) levels and diminishing catalase activity. Moreover, cisplatin upregulated the neuroinflammatory markers (TNF, IL-6, GFAP, and NF-κB). Captopril successfully ameliorated cisplatin damage on the levels of neurobehavioral and histopathological changes. Mechanistically, captopril significantly diminished MDA production and preserved catalase antioxidant activity. Captopril also counteracted neuroinflammation through inhibiting NF-κB and its downstream proinflammatory cytokines besides repressing astrocyte activity by reducing GFAP expression.

CONCLUSION

Our findings revealed that captopril could abrogate cisplatin neurotoxicity via reducing oxidative stress and neuroinflammation thus enhancing cognitive and behavioral performance. This could suggest the repurposing of captopril as a neuroprotective agent, especially in hypertensive cancer patients receiving cisplatin.

Unveiling the mechanism of sericin and hydroxychloroquine in suppressing lung oxidative impairment and early carcinogenesis in diethylnitrosamine-induced mice by modulating PI3K/Akt/Nrf2/NF-κB signaling pathway

This study sheds light on the ameliorative influence of combined sericin and hydroxychloroquine (HQ) on mitigating diethylnitrosamine (DEN)-induced lung oxidative impairment and inflammation, thereby precluding early carcinogenic episodes in mice. Besides, the pivotal role of sericin and HQ in controlling the PI3K/Akt/Nrf2/NF-κB signaling pathway was probed. Therefore, male Swiss albino mice were assigned to different groups and treated with different drugs. Oxidative stress and inflammatory biomarkers, in addition to the expression of PI3K and Akt genes were evaluated in lung tissues. Treatment with DEN disturbed the redox homeostasis associated with inflammation in the lungs. Conversely, sericin combined with HQ remarkably upregulated Nrf2 expression in the lungs associated with significant ameliorations of antioxidant factors, including SOD, GST, GSH, and MDA. Furthermore, sericin and HQ abated inflammation instigated by DEN through downregulating NF-κB and inflammatory biomarkers, including TNF-α and IL-6, with an increase in IL-10. Importantly, sericin and HQ treatment significantly downregulated PI3K and Akt expression. Immunohistochemical investigations demonstrated marked diminutions in Ki-67 and p53 expressions in animals cotreated with sericin and HQ compared to the DEN-treated group, inhibiting lung cancer progression. Histopathological and ultrastructural anomalies were detected in lung tissues from the DEN group, while significant enhancements were perceived in lung tissues treated with sericin and HQ. Our findings emphasized that the combinatorial therapy of sericin and HQ could orchestrate the PI3K/Akt/Nrf2/NF-κB signaling pathway in the lungs, counteracting oxidative stress, inflammation, and uncontrolled cellular proliferation and sustaining lung structures. Furthermore, they could serve as anticancer agents, hindering lung cancer progression.

Captopril exhibits protective effects through anti-inflammatory and anti-apoptotic pathways against hydrogen peroxide-induced oxidative stress in C6 glioma cells

Recent studies have shown that angiotensin-converting enzyme (ACE) inhibitors have reduced oxidative damage in the central nervous system (CNS). Accumulating evidence have also demonstrated that captopril, an ACE inhibitor, has protective effects on the CNS. However, its effects on hydrogen peroxide (H2O2)-induced oxidative damage in glial cells and interaction with the inflammatory system are still uncertain. Therefore, this study was aimed to investigate the protective effect of captopril on glial cell damage after H2O2-induced oxidative stress involved in the inflammatory and apoptotic pathways. The control group was without any treatment, and the H2O2 group was treated with 0.5 mM H2O2 for 24 h. The captopril group was treated with various concentrations of captopril for 24 h. The captopril + H2O2 group was pre-treated with captopril for 1 h and then exposed to 0.5 mM H2O2 for 24 h. In the captopril + H2O2 group, captopril at all concentrations significantly increased the cell viability in C6 cells. It also significantly increased the TAS and decreased the TOS levels which are an indicator of oxidative stress. Moreover, captopril significantly reduced the inflammation markers including NF-kB, IL-1 β, COX-1, and COX-2 levels. Flow cytometry results also exhibited that captopril pretreatment significantly decreased the apoptosis rate. Besides, captopril significantly reduced apoptotic Bax and raised anti-apoptotic Bcl-2 protein levels. In conclusion, captopril has protective effects on C6 cells after H2O2-induced oxidative damage by inhibiting oxidative stress, inflammation, and apoptosis. However, further studies need to be conducted to evaluate the potential of captopril as a neuroprotective agent.

Captopril suppresses hepatic mammalian target of rapamycin cell signaling and biomarkers of inflammation and oxidative stress in thioacetamide-induced hepatotoxicity in rats

BACKGROUND

The potential inhibitory effects of captopril, the angiotensin-converting enzyme inhibitor, on thioacetamide (TAA)-induced hepatic mammalian target of rapamycin (mTOR), liver injury enzymes, blood pressure, and biomarkers of inflammation and oxidative stress have not been investigated before.

MATERIALS AND METHODS

Rats were either injected with TAA (200 mg/kg; twice a week for 8 weeks) before being sacrificed after 10 weeks (model group) or were pretreated with captopril (150 mg/kg) daily for two weeks prior to TAA injections and continued receiving both agents until the end of the experiment (protective group).

RESULTS

Captopril significantly (p < .05) inhibited TAA-induced hypertension, liver tissue levels of mTOR, TIMP-1, TNF-α, IL-6, MDA; and blood levels of lipids, ALT, and AST. We further demonstrated a significant (p < .01) positive correlation between mTOR scoring and the levels of inflammatory, oxidative and liver injury biomarkers.

CONCLUSIONS

Captopril protects against TAA-induced mTOR, liver injury enzymes, dyslipidemia, hypertension, inflammation, and oxidative stress.

Thymoquinone Ameliorates Lung Inflammation and Pathological Changes Observed in Lipopolysaccharide-Induced Lung Injury

Anti-inflammatory, antioxidant, and immunomodulatory effects of thymoquinone (TQ) have been shown. The effects of TQ on lipopolysaccharide- (LPS-) induced inflammation and pathological changes in rats' lung were investigated in this study. Four groups of rats included (1) control (saline treated); (2) LPS (treated with 1 mg/kg/day i.p. for two weeks); and (3 and 4) 5 or 10 mg/kg TQ i.p. 30 min prior to LPS administration. Total and differential WBC counts in the blood and bronchoalveolar fluid (BALF), TGF-β1, INF-γ, PGE2, and IL-4 levels in the BALF and pathological changes of the lung were evaluated. Total WBC count and eosinophil, neutrophil, and monocyte percentage were increased, but the lymphocyte percentage was reduced in the blood and BALF. The BALF levels of PGE2, TGF-β1, and INF-γ were also increased, but IL-4 level was reduced due to LPS administration. LPS also induced pathological insults in the lung of rats (P < 0.05 to P < 0.001 for all changes in LPS-exposed animals). Treatment with TQ showed a significant improvement in all changes induced by LPS (P < 0.05 to P < 0.05). TQ showed a protective effect on LPS-induced lung inflammation and pathological changes in rats which suggested a therapeutic potential for TQ on lung injury.

A protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide in rats

OBJECTIVE

Inflammation has been considered as an important factor in cardiovascular diseases (CVD). Curcumin has been well known for its anti-inflammatory effects. In current research, protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide (LPS) was investigated in rats.

MATERIAL AND METHODS

The animals were divided into five groups and received the treatments during two weeks [1]: Control in which vehicle was administered instead of curcumin and saline was injected instead of LPS [2], LPS group in which vehicle of curcumin plus LPS (1 mg/kg) was administered [3-5], curcumin groups in them three doses of curcumin (5, 10 and 15 mg/kg) before LPS were administered.

RESULTS

Administration of LPS was followed by an inflammation status presented by an increased level of white blood cells (WBC) (p < 0.001). An oxidative stress status was also occurred after LPS injection which was presented by an increased level of malondialdehyde (MDA) while, a decrease in thiols, superoxide dismutase (SOD) and catalase(CAT) in all heart, aorta and serum (p < 0.001). The results also showed that curcumin decreased WBC (doses: 10 and 15 mg/kg) (p < 0.001) accompanying with a decrease in MDA (P < 0.01 and P < 0.001). Curcumin also improved the thiols and the activities of SOD and catalase (P < 0.05, P < 0.01 and P < 0.001).

CONCLUSION

Based on our findings, curcumin can ameliorates oxidative stress and inflammation induced by LPS in rats to protect the cardiovascular system.

Transcriptomic analysis of key genes and pathways in human bronchial epithelial cells BEAS-2B exposed to urban particulate matter

Urban particulate matter (PM), a great danger to public health, is associated with increasing risk of pulmonary diseases. However, the involved key genes and signaling pathways mediating the cellular responses to urban PM are largely unknown. In this study, human bronchial epithelial cells BEAS-2B was exposed to Standard reference material (SRM) 1649b, followed by RNA-sequencing (RNA-seq) and a combination of different bioinformatics analysis. A total of 201 genes (111 upregulated and 90 downregulated) were identified as the differentially expressed genes (DEGs). Moreover, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA) unveiled several significant genes and pathways involved in PM-induced lung toxicity. Protein-protein interaction (PPI) network was performed with the Search Tool for the Retrieval of Interacting Genes (STRING), and the hub gene modules were recognized by Molecular Complex Detection (MCODE), a plug-in of Cytoscape. Moreover, Connectivity Map (CMap) analysis found six candidate small molecular compounds to reverse PM-altered gene expression, including aminohippuric acid, captopril, cinoxacin, fasudil, pargyline, and altizide. Finally, the expressions of part vital genes related to inflammation (IL-1β, CXCL2, CXCL5, CXCL8), ferroptosis (HMOX1, GCLM), and autophagy (BECN1, MAPK1LC3B) were in accordance with the RNA-seq data, with a concentration-dependent manner. This study may be helpful in revealing the complex molecular mechanisms underlying PM-induced lung toxicity and provide some new therapeutic targets for PM-related pulmonary diseases.

Socheongryongtang suppresses COPD-related changes in the pulmonary system through both cytokines and chemokines in a LPS COPD model

Context: Socheongryongtang is a traditional Korean medical prescription used to treat pulmonary diseases.Objective: This study investigated the therapeutic mechanism of socheongryongtang for pulmonary diseases.Materials and methods: Seventy BALB/c mice were used: control, 0.8 mg/kg/study LPS intranasal instillation, 1 mg/kg/day Spiriva oral administration for five days, two socheongryongtang groups (150 or 1500 mg/kg/day orally treatment for five days). To illuminate the anti-COPD mechanism, several factors were evaluated such as WBC and differential counts in BALF and IgE in serum, morphological changes, and changes of COPD-related cytokines (TNF-α, IFN-γ, TGF-β) and chemokines (CXCL1, CCL-2, CCR2) in the lung. In order to confirm the statistical significance, all results were compared under p < 0.01 and p < 0.05.Results: LPS induced a high level of WBC, neutrophils and eosinophils in our in vivo study. Additionally, COPD related cytokines and chemokines such as TNF-α, IFN-γ, TGF-β, CXCL1, CCL-2 and CCR2 were induced by LPS. Compared to the LPS treatment group, socheongryongtang significantly controlled the level of WBC, neutrophils and eosinophils as well as the level of IgE. It effectively down-regulated the morphological changes, such as fibrosis near bronchoalveolar spaces, small airway destruction (emphysema), etc. It also inhibited the levels of COPD-related cytokines (TNF-α, IFN-γ, TGF-β) and chemokines (CXCL1, CCL-2, CCR2) compared to the LPS treatment group. In particular, socheongryongtang significantly down-regulated the levels of TNF-α, IFN-γ, and CCR2.Conclusions: Socheongryongtang controlled COPD, but as it has been used as a prescription for respiratory disease, we should additionally evaluate the therapeutic effects against various pulmonary diseases.

Treadmill exercise ameliorates memory deficits and hippocampal inflammation in ovalbumin-sensitized juvenile rats

The behavioral changes, including spatial learning and memory impairment as well as depressive- and anxiety-like behaviors in an animal model of asthma were demonstrated previously. On the other hand, there is increasing evidence that the anti-inflammatory actions of exercise are related to their neuroprotective properties against different insults in the brain. This study was aimed to explore the effects of moderate treadmill exercise on cognitive deficits and possible anti-inflammatory mechanisms in ovalbumin (OVA)-sensitized rats. The exercise groups were trained to run on the treadmill 30 min/day with an intensity of 12 m/min, 5 days/week for 4 weeks. Animals in the OVA groups were sensitized by two intraperitoneal (i.p.) injections of OVA (10 μg/injection) and challenged with OVA by inhalation during the treadmill running exercise period. Passive avoidance (PA) memory, levels of interleukin (IL)-10 and tumor necrosis factor (TNF)-α in the hippocampus, total and differential white blood cell (WBC) count in the blood as well as pathological changes of the lung were then evaluated. OVA-sensitization was resulted in cognitive deficits in the PA task, along with increased total and differential WBC in blood and TNF-α in the hippocampus. However, exercise ameliorated these changes and increased the IL-10 level in the hippocampus, suggesting that moderate treadmill exercise can improve memory impairment in OVA-sensitized rats due to its anti-inflammatory properties.

Echinacea polysaccharide alleviates LPS-induced lung injury via inhibiting inflammation, apoptosis and activation of the TLR4/NF-κB signal pathway

Lung injury is a common critical life-threatening syndrome. Inflammation is a key factor in the pathogenesis of lung injury. It is reported that Echinacea Polysaccharides (EP) has anti-inflammatory activity. However, the effect of EP on lung injury remains unclear. In our study, murine model of lung injury was induced with 2.5 mg/kg LPS before administration of 5 mg/kg or 10 mg/kg EP. EP ameliorated LPS-induced lung pathological damage, along with reduction in lung wet/dry weight ratio and myeloperoxidase activity. EP decreased the number of leukocytes, eosinophils, neutrophils, lymphocytes and macrophages in bronchoalveolar lavage fluid, and the release of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in LPS-treated lung. EP suppressed LPS-induced apoptosis along with down-regulation of Bcl2-associated X (Bax) and cleaved caspase-3 (CC3), and elevated B-cell lymphoma-2 (Bcl-2). Besides, RAW 264.7 cells were treated with EP 100 μg/ml for 1 h and then incubated with 1 μg/ml LPS for 24 h. TNF-α, IL-6 and IL-1β levels were lowered by treatment of EP in LPS-treated RAW 264.7 cells. Moreover, EP down-regulated the expression of toll-like receptor 4 (TLR4), myeloid differentiating factor 88 (MyD88), p-IκBα, nuclear factor kappa-B (NF-κB), p-NF-κB, and up-regulated the inhibitor of NF-κB (IκBα) in vivo and in vitro following LPS induction, which is consistent with the effect of TAK-242. In conclusion, EP may alleviate LPS-induced lung injury via inhibiting inflammation, apoptosis and activation of TLR4/NF-κB signal pathway.

Inhibition of HtrA2 alleviates inflammatory response and cell apoptosis in lipopolysaccharide‑induced acute pneumonia in rats

Pneumonia is one of the commonest causes of death worldwide. High-temperature requirement A2 (HtrA2) is a proapoptotic mitochondrial serine protease involved in caspase-dependent or caspase-independent cell apoptosis. UCF-101 (5-[5-(2-nitrophenyl) furfuryl iodine]-1,3-diphenyl-2-thiobarbituric acid), an inhibitor of HtrA2, has a protective effect on organs in various diseases by inhibiting cell apoptosis. The aim of the present study was to explore whether UCF-101 has a protective effect on lungs in pneumonia. A lipopolysaccharide (LPS)-induced pneumonia model was established in rats. UCF-101 (2 µmol/kg) was used for treatment. Lung injury was detected by hematoxylin and eosin staining. Pro-inflammatory cytokines and oxidative stress-related factors were detected using corresponding test kits. TUNEL staining was used to measure the amount of cell apoptosis. Apoptosis-associated proteins were detected by western blot assay. The present study indicated pulmonary injury induced by LPS. Treatment with UCF-101 clearly alleviated this pulmonary damage and restored the levels of pro-inflammatory cytokines and oxidative stress-related factors. In addition, UCF-101 significantly reduced LPS-induced cell apoptosis, the release of HtrA2 and cytochrome from mitochondria to the cytoplasm and inhibited the expression of pro-apoptotic proteins. UCF-101 also restored the ATP level. The present results demonstrated that UCF-101 acts as a positive regulator of acute pneumonia by inhibiting inflammatory response, oxidative stress and mitochondrial apoptosis. The present study suggests UCF-101 as a potential candidate for pneumonia therapy.

Epithelial Dysfunction in Lung Diseases: Effects of Amino Acids and Potential Mechanisms

Lung diseases affect millions of individuals all over the world. Various environmental factors, such as toxins, chemical pollutants, detergents, viruses, bacteria, microbial dysbiosis, and allergens, contribute to the development of respiratory disorders. Exposure to these factors activates stress responses in host cells and disrupt lung homeostasis, therefore leading to dysfunctional epithelial barriers. Despite significant advances in therapeutic treatments for lung diseases in the last two decades, novel interventional targets are imperative, considering the side effects and limited efficacy in patients treated with currently available drugs. Nutrients, such as amino acids (e.g., arginine, glutamine, glycine, proline, taurine, and tryptophan), peptides, and bioactive molecules, have attracted more and more attention due to their abilities to reduce oxidative stress, inhibit apoptosis, and regulate immune responses, thereby improving epithelial barriers. In this review, we summarize recent advances in amino acid metabolism in the lungs, as well as multifaceted functions of amino acids in attenuating inflammatory lung diseases based on data from studies with both human patients and animal models. The underlying mechanisms for the effects of physiological amino acids are likely complex and involve cell signaling, gene expression, and anti-oxidative reactions. The beneficial effects of amino acids are expected to improve the respiratory health and well-being of humans and other animals. Because viruses (e.g., coronavirus) and environmental pollutants (e.g., PM2.5 particles) induce severe damage to the lungs, it is important to determine whether dietary supplementation or intravenous administration of individual functional amino acids (e.g., arginine-HCl, citrulline, N-acetylcysteine, glutamine, glycine, proline and tryptophan) or their combinations to affected subjects may alleviate injury and dysfunction in this vital organ.

The protective effect of Nigella sativa extract on lung inflammation and oxidative stress induced by lipopolysaccharide in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Oxidative stress during inflammation can increase inflammation and damage tissue. Nigella sativa L. (NS) showed many pharmacological properties including antioxidant and anti-inflammatory activities.

AIM OF THE STUDY

In this study, the preventive effect of NS on lung inflammation and oxidative stress induced by lipopolysaccharide (LPS) in the rats was investigated.

MATERIALS AND METHODS

Male rats were assigned to: Control, LPS (1 mg/kg, i.p.), LPS + NS (100, 200, 400 mg/kg, i.p.), (10 per group). Saline (1 ml/kg) was intra-peritoneal (i.p.) injected instead of LPS in the rats of the control group. LPS dissolved in saline and injected i.p. daily for 14 days. Treatment with NS extracts started two days before LPS administration and treatment continued during LPS administration. White blood cells (WBC), total and differential as well as oxidative stress index in bronchoalveolar fluid (BALF) and serum, TGF-β1, IFN-γ, PGE2, and IL-4 levels in the BALF and lung histopathology were examined.

RESULTS

LPS administration increased total WBC, eosinophils, neutrophils, basophils, and monocytes counts as well as oxidative stress markers in the BALF and serum as well as TGF-β1, IFN-γ, PGE2, IL-4 levels in the BALF and pathological changes of the lung tissue. All of these effects were reduced by NS extract treatment dose-dependently.

CONCLUSION

These results suggested the protective effects of NS extract on lung inflammation and oxidative stress as well as its effect on lung pathology induced by LPS dose-dependently.

Aminoguanidine affects systemic and lung inflammation induced by lipopolysaccharide in rats

BACKGROUND

Nitric oxide is a mediator of potential importance in numerous physiological and inflammatory processes in the lung. Aminoguanidine (AG) has been shown to have anti-inflammation and radical scavenging properties. This study aimed to investigate the effects of AG, an iNOS inhibitor, on lipopolysaccharide (LPS)-induced systemic and lung inflammation in rats.

METHODS

Male Wistar rats were divided into control, LPS (1 mg/kg/day i.p.), and LPS groups treated with AG 50, 100 or 150 mg/kg/day i.p. for five weeks. Total nitrite concentration, total and differential white blood cells (WBC) count, oxidative stress markers, and the levels of IL-4, IFN-γ, TGF-β1, and PGE2 were assessed in the serum or bronchoalveolar lavage fluid (BALF).

RESULTS

Administration of LPS decreased IL-4 level (p < 0.01) in BALF, total thiol content, superoxide dismutase (SOD) and catalase (CAT) activities (p < 0.001) in BALF and serum, and increased total nitrite, malondialdehyde (MDA), IFN-γ, TGF-β1 and PGE2 (p < 0.001) concentrations in BALF. Pre-treatment with AG increased BALF level of IL-4 and total thiol as well as SOD and CAT activities (p < 0.05 to p < 0.001), but decreased BALF levels of total nitrite, MDA, IFN-γ, TGF-β1, and PGE2 (p < 0.01 to p < 0.001). AG treatment decreased total WBC count, lymphocytes and macrophages in BALF (p < 0.01 to p < 0.001) and improved lung pathological changes including interstitial inflammation and lymphoid infiltration (p < 0.05 to p < 0.001).

CONCLUSIONS

AG treatment reduced oxidant markers, inflammatory cytokines and lung pathological changes but increased antioxidants and anti-inflammatory cytokines. Therefore, AG may play a significant protective role against inflammation and oxidative stress that cause lung injury.