Docosahexaenoic acid (DHA) attenuated paraquat induced lung damage in mice

Docosahexaenoic acid (DHA) alleviates inflammation and damage induced by experimental colitis

PURPOSE

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic gastrointestinal disorders associated with significant morbidity and complications. This study investigates the therapeutic potential of docosahexaenoic acid (DHA) in a trinitrobenzene sulfonic acid (TNBS) induced colitis model, focusing on inflammation, oxidative stress, and intestinal membrane permeability.

METHODS

Wistar albino rats were divided into Control, Colitis, and Colitis + DHA groups (n = 8-10/group). The Colitis and Colitis + DHA groups received TNBS intrarectally, while the Control group received saline. DHA (600 mg/kg/day) or saline was administered via gavage for six weeks. Macroscopic and microscopic evaluations of colon tissues were conducted. Parameters including occludin and ZO-1 expressions, myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), total antioxidant status (TAS), total oxidant status (TOS), Interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) levels were measured in colon tissues.

RESULTS

Colitis induction led to significantly higher macroscopic and microscopic damage scores, elevated TOS levels, reduced occludin and ZO-1 intensity, decreased mucosal thickness, and TAS levels compared to the Control group (p < 0.001). DHA administration significantly ameliorated these parameters (p < 0.001). MPO, MDA, TNF-α, and IL-6 levels were elevated in the Colitis group but significantly reduced in the DHA-treated group (p < 0.001 for MPO, MDA; p < 0.05 for TNF-α and IL-6).

CONCLUSION

DHA demonstrated antioxidant and anti-inflammatory effects by reducing reactive oxygen species production, enhancing TAS capacity, preserving GSH content, decreasing proinflammatory cytokine levels, preventing neutrophil infiltration, reducing shedding in colon epithelium, and improving gland structure and mucosal membrane integrity. DHA also upregulated the expressions of occludin and ZO-1, critical for barrier function. Thus, DHA administration may offer a therapeutic strategy or supplement to mitigate colitis-induced adverse effects.

Metabolomics approach in lung tissue of septic rats and the interventional effects of Xuebijing injection using UHPLC-Q-Orbitrap-HRMS

Sepsis is the dysregulated host response to an infection which leads to life-threatening organ dysfunction. Metabolomic profiling in bio-fluid or tissue is vital for elucidating the pathogenesis of sepsis and evaluating therapeutic effects of medication. In this study, an untargeted metabolomics approach was applied to study the metabolic changes in lung tissue of septic rats induced by cecal ligation and puncture (CLP) and investigate the treatment effects of Xubijing injection (XBJ). Metabolomics analyses were performed on ultra-high performance liquid chromatography-Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry (UHPLC-Q-Orbitrap-HRMS) together with multivariate statistical analysis. A total of 26 differential metabolites between CLP and sham-operated group were identified. The altered metabolic pathways included energy metabolism, amino metabolism, lipid metabolism, fatty acid metabolism and hormone metabolism. Among the 26-varied metabolites, 15 were significantly regulated after XBJ treatment. The metabolic pathway network of sepsis was drawn to interpret the pathological feature of lung damage caused by sepsis and the underlying regulating mechanism of XBJ on the molecular levels. Our findings display that LC-MS-based metabolomics is a useful tool for uncovering the underlying molecular mechanism of sepsis, and XBJ may exert therapeutic effect by regulating multiple metabolic pathways.

Protective Effect of Anthocyanin on Paraquat-Induced Apoptosis and Epithelial-Mesenchymal Transition in Alveolar Type II Cells

BACKGROUND Paraquat (PQ) can over-accumulate in alveolar epithelial cells. Anthocyanin (An) can exert anti-oxidative properties. The role of An in PQ-induced toxicity is unclear, so we aimed to explore whether An could inhibit epithelial mesenchymal transition (EMT) induced by PQ in alveolar cells. MATERIAL AND METHODS lveolar epithelial cells were treated with PQ and An with concentration gradient for 12, 24, and 48 h. The cell viability, ROS level, and apoptosis rate were determined using the Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The lactate dehydrogenase (LDH) leakage, methane dicarboxylic aldehyde (MDA) level, glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities were determined by spectrophotometric method. The mRNA and protein expressions were detected using quantitative real-time PCR (qPCR) and Western blot, respectively. RESULTS An reduced the PQ-induced apoptosis in a dose-dependent manner. Moreover, An reduced the ratio of Bax/Bcl-2 to ROS level. We found that An suppressed the activity of LDH and MDA and improved SOD and GPX levels. Additionally, the level of PQ-induced E-cadherin was decreased by An while the expressions of vimentin, α-smooth muscle actin (α-SMA), and collagens type I (col-I) were increased. Furthermore, An inhibited the levels of transforming growth factor β1 (TGF-β1) and activin receptor-like kinase 5 (ALK5) and reduced the phosphorylation of smad2. CONCLUSIONS Our study shows newly discovered effects of anthocyanidins on EMT and supports their chemopreventive effects in paraquat-induced apoptosis in alveolar type II cells.

Endogenous ω-3 Fatty Acid Production by fat-1 Transgene and Topically Applied Docosahexaenoic Acid Protect against UVB-induced Mouse Skin Carcinogenesis

The present study was intended to explore the effects of endogenously produced ω-3 polyunsaturated fatty acids (PUFAs) on ultraviolet B (UVB)-induced skin inflammation and photocarcinogenesis using hairless fat-1 transgenic mice harboring ω-3 desaturase gene capable of converting ω-6 to ω-3 PUFAs. Upon exposure to UVB irradiation, fat-1 transgenic mice exhibited a significantly reduced epidermal hyperplasia, oxidative skin damage, and photocarcinogenesis as compared to wild type mice. The transcription factor, Nrf2 is a master regulator of anti-inflammatory and antioxidant gene expression. While the protein expression of Nrf2 was markedly enhanced, the level of its mRNA transcript was barely changed in the fat-1 transgenic mouse skin. Topical application of docosahexaenoic acid (DHA), a representative ω-3 PUFA, in wild type hairless mice induced expression of the Nrf2 target protein, heme oxygenase-1 in the skin and protected against UVB-induced oxidative stress, inflammation and papillomagenesis. Furthermore, transient overexpression of fat-1 gene in mouse epidermal JB6 cells resulted in the enhanced accumulation of Nrf2 protein. Likewise, DHA treated to JB6 cells inhibited Nrf2 ubiquitination and stabilized it. Taken together, our results indicate that functional fat-1 and topically applied DHA potentiate cellular defense against UVB-induced skin inflammation and photocarcinogenesis through elevated activation of Nrf2 and upregulation of cytoprotective gene expression.

The alpha-lipoic acid derivative DHLHZn: a new therapeutic agent for acute lung injury in vivo

OBJECTIVE AND DESIGN

An animal experiment was performed to demonstrate the anti-inflammatory effects of an alpha-lipoic acid (ALA) derivative, dihydrolipoyl histidinate zinc complex (DHLHZn) for acute lung injury (ALI) and to investigate the mechanism of action.

MATERIAL

Rats were randomly divided into three experimental groups: control group (n = 17), DHLHZn(-) group (n = 11, ALI model rats), and DHLHZn(+) group (n = 12, ALI model rats treated by DHLHZn).

TREATMENT

Lipopolysaccharides (LPS, 10 mg/kg) were administered intratracheally in the DHLHZn(-) group and the DHLHZn(+) group. For the DHLHZn(+) group, DHLHZn (100 mg/kg) was administered intraperitoneally 2 h prior to LPS administration.

METHODS

Four hours after LPS administration, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The findings were analyzed using the Mann-Whitney U test.

RESULTS

Total number of cells, number of neutrophils and lymphocytes, levels of various inflammatory cytokines, and NF-kB p65 concentration of BALF were significantly lower in the DHLHZn(+) group than in the DHLHZn(-) group (p < 0.05). ALI pathology scores were significantly lower in the DHLHZn(+) group than in the DHLHZn(-) group (p < 0.001).

CONCLUSIONS

Anti-inflammatory effects of DHLHZn for ALI were demonstrated by BALF and histopathological findings. The mechanism of action of DHLHZn was considered to be via inhibition of the NF-kB signaling pathway. DHLHZn is thus suggested to be a new prophylactic agent for ALI.

Selenium–phycocyanin from selenium-enriched cultures of Nostoc sp. isolated from rice field prevents human kidney cells from paraquat-induced damage

Herein we demonstrate that Se-containing phycocyanin (Se–PC) purified from Se-enriched cultures of Nostoc sp. could reverse paraquat (PQ)-induced DNA cell apoptosis through inhibition of superoxide overproduction in human kidney cells.

Protective Effects of Arachidonic Acid Against Paraquat-Induced Pulmonary Injury

In this study, we aimed to study the effects of arachidonic acid (AA) on acute lung injury (ALI) caused by paraquat (PQ) in mice. Male Kunming mice were randomly divided into three groups: control group, PQ group, and PQ + AA group (n = 24). The mice in the PQ and PQ + AA groups received a single oral dose of 20 mg/kg bodyweight PQ, and the mice of the PQ + AA group were challenged by 500 mg/kg bodyweight AA posttreatment 2 h after PQ administration. The results indicated that the administration of AA significantly increased the activity of superoxide dismutase (SOD), decreased the activity of myeloperoxidase (MPO), the content of malondialdehyde (MDA), and the level of lactate dehydrogenase (LDH). Pathological examination also revealed that AA effectively alleviated PQ-induced histological damage. Furthermore, AA significantly reduced PQ-induced upregulations of inflammatory mediators such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8. These results demonstrated that AA had effective protection against PQ-induced ALI.

Enhanced Resolution of Hyperoxic Acute Lung Injury as a result of Aspirin Triggered Resolvin D1 Treatment

Acute lung injury (ALI), which presents as acute respiratory failure, is a major clinical problem that requires aggressive care, and patients who require prolonged oxygen exposure are at risk of developing this disease. Although molecular determinants of ALI have been reported, the molecules involved in disease catabasis associated with oxygen toxicity have not been well studied. It has been reported that lung mucosa is rich in omega-3 fatty acid dicosahexanoic acid (DHA), which has antiinflammatory properties. Aspirin-triggered resolvin D1 (AT-RvD1) is a potent proresolution metabolite of DHA that can curb the inflammatory effects in various acute injuries, yet the effect of AT-RvD1 on hyperoxic acute lung injury (HALI) or in the oxygen toxicity setting in general has not been investigated. The effects of AT-RvD1 on HALI were determined for the first time in 8- to 10-week-old C57BL/6 mice that were exposed to hyperoxia (≥95% O2) for 48 hours. Mice were given AT-RvD1 (100 ng) in saline or a saline vehicle for 24 hours in normoxic (≈21% O2) conditions after hyperoxia. Lung tissue and bronchoalveolar lavage (BAL) fluid were collected for analysis associated with proinflammatory signaling and lung inflammation. AT-RvD1 treatment resulted in reduced oxidative stress, increased glutathione production, and significantly decreased tissue inflammation. AT-RvD1 treatment also significantly reduced the lung wet/dry ratio, protein in BAL fluid, and decreased apoptotic and NF-κB signaling. These results show that AT-RvD1 curbs oxygen-induced lung edema, permeability, inflammation, and apoptosis and is thus an effective therapy for prolonged hyperoxia exposure in this murine model.

Can maternal DHA supplementation offer long-term protection against neonatal hyperoxic lung injury?

The effect of adverse perinatal environment (like maternal infection) has long-standing effects on many organ systems, including the respiratory system. Use of maternal nutritional supplements is an exciting therapeutic option that could be used to protect the developing fetus. In a recent issue of the journal, Ali and associates (Ali M, Heyob KM, Velten M, Tipple TE, Rogers LK. Am J Physiol Lung Cell Mol Physiol 309: L441-L448, 2015) specifically look at maternal docosahexaenoic acid (DHA) supplementation and its effect on chronic apoptosis in the lung in a mouse model of perinatal inflammation and postnatal hyperoxia. Strikingly, the authors show that pulmonary apoptosis was augmented even 8 wk after the hyperoxia-exposed mice had been returned to room air. This effect was significantly attenuated in mice that were subjected to maternal dietary DHA supplementation. These findings are novel, significantly advance our understanding of chronic effects of adverse perinatal and neonatal events on the developing lung, and thereby offer novel therapeutic options in the form of maternal dietary supplementation with DHA. This editorial reviews the long-term effects of adverse perinatal environment on postnatal lung development and the protective effects of dietary supplements such as DHA.

Protective effect of Xuebijing injection on paraquat-induced pulmonary injury via down-regulating the expression of p38 MAPK in rats

Background

Exposure to paraquat results in acute lung injury. A systemic inflammatory response has been widely established as a contributor to paraquat-induced acute lung injury. Recent studies have reported that consumption of Xuebijing prevents inflammatory response-induced diseases. This study investigated whether consumption of Xuebijing protected rats against paraquat-induced acute lung injury.

Methods

Adult male Sprague Dawley rats were randomly divided into four groups: control group; paraquat group; paraquat + Xuebijing group; and paraquat + dexamethasone group. Rats in the paraquat, paraquat + Xuebijing and paraquat + dexamethasone groups were intraperitoneally injected with paraquat (30 mg/kg) or administered paraquat and Xuebijing at 8 mL/kg or dexamethasone at 5 mg/kg, respectively, via an injection into the tail vein. Lung p38 MAPK, NF-κB65, IkB, p-IκB-α, HIF-1α, Nrf2 and TGF-β1 expression were essayed using western blotting. IL-6, TNF-α, IL-1β, IL-10, TGF-β1 and PIIIP were measured using ELISA. ROS, oxidised glutathione and glutathione activity were measured.

Results

After inducing acute lung injury with paraquat for 24 h, Xuebijing was observed to block lung p-p38 MAPK, NF-κB65, HIF-1α, p-IκB-α and TGF-β1 expression, and increased Nrf2 and IkB expression. The numbers of neutrophils and lymphocytes and total number of cells were significantly lower in the Xuebijing group compared with the control group. IL-6, TNF-α, IL-1β, TGF-β1 and PIIIP levels were significantly decreased in the Xuebijing group. ROS and oxidised glutathione activity were markedly inhibited by Xuebijing. Histological evaluation showed attenuation of the effects of Xuebijing on paraquat-induced lung injury. Compared with the paraquat + dexamethasone group, the Xuebijing + paraquat group showed no significant differences.

Conclusions

Inhibiting the expression of p38 MAPK and NF-κB65 was crucial for the protective effects of Xuebijing on paraquat-induced acute lung injury. The findings suggest that Xuebijing could effectively ameliorate paraquat-induced acute lung injury in rats. Xuebijing was as effective as dexamethasone at improving paraquat-induced lung injury by regulating lung inflammation, lung function and oxidative stress responses.

Metallothioneins attenuate paraquat-induced acute lung injury in mice through the mechanisms of anti-oxidation and anti-apoptosis

Paraquat (PQ) is a widely used herbicide, and lung is the primary target of PQ poisoning. Metallothionein (MT) is a potent antioxidant and free radical scavenger, and has been shown to play a protective role in lung injury induced by different stressors. This study was undertaken to evaluate the protective potential of MT against PQ-induced acute lung injury using MT-I/II null (MT(-/-)) mice. Wild-type (MT(+/+)) mice and MT(-/-) mice were given one intragastric administration of 50mg/kg PQ for 24h, and it was revealed that MT(-/-) mice were more susceptible to PQ-induced acute lung injury than MT(+/+) mice evidenced by the following findings. As compared with MT(+/+) mice, MT(-/-) mice presented more severe histopathological lesions in the lung, higher pulmonary malondialdehyde content, and more reduced pulmonary antioxidative enzymes activities. PQ also induced more apoptosis in pneumocytes from MT(-/-) mice, and the expressions of apoptosis-related proteins Bax, Bcl-2, cleaved-caspase-3, and the ratio of Bax/Bcl-2 were all more significantly increased in PQ-treated MT(-/-) mice. Our results clearly demonstrate that endogenous MT can attenuate PQ-induced acute lung injury, possibly through the mechanisms of anti-oxidation and anti-apoptosis.

Molecular mechanisms of paraquat-induced acute lung injury: a current review

Paraquat is an organic heterocyclic herbicide that is widely used in agriculture, especially in Asian countries. The prevalence of paraquat poisonings has increased dramatically in the past two decades in China. Nearly all paraquat poisonings resulted from intentional or accidental oral administration leading to acute lung injury and, ultimately, acute respiratory distress syndrome. The mortality rate has been reported to be greater than 90%. However, the exact toxic mechanism remains unclear. Herein, we reviewed and summarized the most recent publications related to the molecular mechanisms of paraquat-induced acute lung injury.