Lung Histopathological Changes Research Articles

Cinobufagin alleviates lipopolysaccharide-induced acute lung injury by regulating autophagy through activation of the p53/mTOR pathway.

Acute lung injury (ALI) is a severe clinical disorder characterized by dysregulated inflammatory responses, leading to high rates of morbidity and mortality. Cinobufagin, a primary component isolated from cinobufotalin, exerts strong anticancer effects. However, there are few reports on its role in ALI, and it is unclear whether cinobufagin affects lipopolysaccharide (LPS)-induced ALI. Therefore, the present study aimed to investigate the effect of cinobufagin on LPS-induced ALI and to assess its potential mechanism of action. The results showed that cinobufagin alleviated lung histopathological changes and protected the permeability of lung tissues in LPS-induced ALI. In addition, cinobufagin effectively suppressed inflammatory responses through the induction of autophagy in LPS-induced ALI cells and in a mouse model. Moreover, cinobufagin enhanced autophagy through the p53/mTOR pathway in LPS-induced ALI. Herein, it was reported for the first time that cinobufagin inhibited the inflammatory response of LPS-induced ALI, which laid the foundation for further understanding and development of cinobufagin as a potential new drug for ALI.

Anti-inflammatory potential of turmeric, amla, and black pepper mixture against sepsis-induced acute lung injury in rats.

Acute lung injury (ALI), is a severe inflammatory lung disease. We tested the prophylactic effect of a functional food mix comprising three anti-inflammatory plant products: turmeric, amla, and black pepper (TAB) against lipopolysaccharide (LPS)-induced ALI in rats. Two-month-old male Wistar rats were randomly divided into three groups: control (C), LPS (5mg/kg), and LPS with TAB (TAB). After 6h of LPS injection, the rats were sacrificed by cervical decapitation to collect the lung tissue. Results showed that TAB partially ameliorated LPS-induced increase in circulating inflammatory cytokines (TNFα and IL6) and significantly prevented lung histopathological changes. TAB also suppressed LPS-activated ER stress markers (GRP78, pIRE1, and CHOP) and apoptotic markers (caspase-3 and - 12) in the lung. The anti-inflammatory effects of the TAB support its potential use as an adjuvant to mitigate ALI. Importantly, TAB's ingredients have been used for centuries as part of the diet with limited or no toxic effects.

Protective effect of genkwanin against lipopolysaccharide-induced acute lung injury in mice with p38 mitogen-activated protein kinase and nuclear factor-κB pathway inhibition

• Genkwanin inhibited the lung histopathological changes in LPS-induced ALI mice. • Genkwanin inhibited lung oedema, alveolar–capillary barrier, and leukocytes infiltration dysfunction in LPS-induced ALI mice. • Genkwanin reduced the secretion of IL-1β, IL-6, and TNF-α in LPS-induced ALI mice. • Genkwanin reduced IκB degradation and p65 phosphorylation in LPS-induced ALI mice. • Genkwanin reduced p38 MAPK phosphorylation in LPS-induced ALI mice. Acute lung injury (ALI) is a life-threatening clinical syndrome. Genkwanin is a nonglycosylated flavonoid that has several biopharmacological effects, such as anti-inflammatory, antioxidative, and immunomodulator effects. This study investigated the protective effect and mechanism of genkwanin in a lipopolysaccharide (LPS)-induced mouse model. Histopathological analysis indicated that genkwanin had a potential ameliorative effect on LPS-induced ALI. Genkwanin also inhibited several pathogenic features induced by LPS, including lung oedema, alveolar-capillary barrier dysfunction, and leukocyte and neutrophil infiltration. In addition, it inhibited NF-κB pathway activation, including phosphorylation of p65 and degradation of IκB, induced by LPS. Genkwanin also inhibited the phosphorylation of the p38 MAPK pathway induced by LPS, although it did not inhibit the phosphorylation of extracellular signal-regulated kinases or c-Jun N -terminal kinases induced by LPS. In conclusion, our results indicate that genkwanin has a protective effect against LPS-induced ALI that it exerts by inhibiting NF-κB pathway activation and p38 MAPK phosphorylation.

The effects of hydrogen treatment in a cigarette smoke solution-induced chronic obstructive pulmonary disease-like changes in an animal model.

Molecular hydrogen, with its antioxidant and anti-inflammatory properties, may be suitable for the prevention and treatment of chronic obstructive pulmonary disease (COPD). This study aims to investigate the therapeutic efficacy of hydrogen-oxygen (H2/O2) treatment in cigarette smoke solution (CSS)-induced COPD-like injury in a female BALB/c mouse model. Thirty mice were randomly assigned to three groups: Control (n=8), COPD (n=10), and COPD + H2/O2 (n=12). CSS was administered by intraperitoneal (IP) injection twice weekly for 6 weeks during the COPD induction phase. Simultaneously, the COPD + H2/O2 group started received 75 minutes of inhalation therapy (42% H2) delivered by the Oxy-Hydrogen Generator twice daily for 9 weeks. Mice body weights and survival were measured throughout the study period. Neutrophil elastase (NE) activity and lung histopathological changes were also evaluated. The results showed a higher survival rate in the COPD + H2/O2 group compared to the COPD group (100% vs. 80%) during the induction phase. Slight decreases in body weight gains were observed in the COPD and COPD + H2/O2 groups during the first 15 days of the induction phase, but there was no significant difference in mean body weights among the three groups throughout the study period. NE activity was numerically lower in the COPD + H2/O2 group compared to the COPD group. The histopathological evaluation showed significant improvements in the H2/O2-treated mice with respect to mean linear intercept (MLI) and lesion (inflammation and emphysema) scores. Improvements in goblet cell hypertrophy and hyperplasia of airway epithelium were not significant. A 9-week H2/O2 inhalation therapy delivered by the Oxy-Hydrogen Generator to CSS-induced COPD-like injury in mice showed improvement in survival rate, alveolar structural changes, and histopathological lesion scores of the lung.

Transmission and pathogenicity of canine H3N2 influenza virus in dog and guinea pig models

BackgroundInfluenza A virus causes respiratory disease in many animal species as well as in humans. Due to the high human-animal interface, the monitoring of canine influenza in dogs and the study of the transmission and pathogenicity of canine influenza in animals are important.MethodsEight-week-old beagle dogs (Canis lupus familaris) (n = 13) were used for the intraspecies transmission model. The dogs were inoculated intranasally with 1 ml of 106 EID50 per ml of canine H3N2 influenza virus (A/canine/Thailand/CU-DC5299/2012) (CIV-H3N2). In addition, 4-week-old guinea pigs (Cavia porcellus) (n = 20) were used for the interspecies transmission model. The guinea pigs were inoculated intranasally with 300 µl of 106 EID50 per ml of CIV-H3N2.ResultsFor the Thai CIV-H3N2 challenged in the dog model, the incoculated and direct contact dogs developed respiratory signs at 2 dpi. The dogs shed the virus in the respiratory tract at 1 dpi and developed an H3-specific antibody against the virus at 10 dpi. Lung congestion and histopathological changes in the lung were observed. For the Thai CIV-H3N2 challenge in the guinea pig model, the incoculated, direct contact and aerosol-exposed guinea pigs developed fever at 1–2 dpi. The guinea pigs shed virus in the respiratory tract at 2 dpi and developed an H3-specific antibody against the virus at 7 dpi. Mild histopathological changes in the lung were observed.ConclusionThe result of this study demonstrated evidence of intraspecies and interspecies transmission of CIV-H3N2 in a mammalian model.

Jinhua Qinggan granules attenuates acute lung injury by promotion of neutrophil apoptosis and inhibition of TLR4/MyD88/NF-κB pathway

Ethnopharmacological relevanceAcute lung injury (ALI) is one of the fatal complications of respiratory virus infections such as influenza virus and coronavirus, which has high clinical morbidity and mortality. Jinhua Qinggan granules (JHQG) has been approved by China Food and Drug Administration in the treatment of H1N1 influenza and mild or moderate novel coronavirus disease 2019 (COVID-19), which is an herbal formula developed based on Maxingshigan decoction and Yinqiao powder that have been used to respiratory diseases in China for thousands of years. However, the underlying mechanism of JHQG in treating infectious diseases remains unclear. Aim of the studyThis study investigated the effects of JHQG on neutrophil apoptosis and key signaling pathways in lipopolysaccharide (LPS) -induced ALI mice in order to explore its mechanism of anti-inflammation. Materials and methodsThe effect of JHQG on survival rate was observed in septic mouse model by intraperitoneal injection of LPS (20 mg/kg). To better pharmacological evaluation, the mice received an intratracheal injection of 5 mg/kg LPS. Lung histopathological changes, wet-to-dry ratio of the lungs, and MPO activity in the lungs and total protein concentration, total cells number, TNF-α, IL-1β, IL-6, and MIP-2 levels in BALF were assessed. Neutrophil apoptosis rate was detected by Ly6G-APC/Annexin V-FITC staining. Key proteins associated with apoptosis including caspase 3/7 activity, Bcl-xL and Mcl-1 were measured by flow cytometry and confocal microscope, respectively. TLR4 receptor and its downstream signaling were analyzed by Western blot assay and immunofluorescence, respectively. ResultsJHQG treatment at either 6 or 12 g/kg/day resulted in 20% increase of survival in 20 mg/kg LPS-induced mice. In the model of 5 mg/kg LPS-induced mice, JHQG obviously decreased the total protein concentration in BALF, wet-to-dry ratio of the lungs, and lung histological damage. It also attenuated the MPO activity and the proportion of Ly6G staining positive neutrophils in the lungs, as well as the MIP-2 levels in BALF were reduced. JHQG inhibited the expression of Mcl-1 and Bcl-xL and enhanced caspase-3/7 activity, indicating that JHQG partially acted in promoting neutrophil apoptosis via intrinsic mitochondrial apoptotic pathway. The levels of TNF-α, IL-1β, and IL-6 were significantly declined in LPS-induced mice treated with JHQG. Furthermore, JHQG reduced the protein expression of TLR4, MyD88, p-p65 and the proportion of nuclei p65, suggesting that JHQG treatment inhibited TLR4/MyD88/NF-κB pathway. ConclusionJHQG reduced pulmonary inflammation and protected mice from LPS-induced ALI by promoting neutrophil apoptosis and inhibition of TLR4/MyD88/NF-κB pathway, suggesting that JHQG may be a promising drug for treatment of ALI.

Activation of cannabinoid receptor 2 alleviates acute lung injury in rats with lipopolysaccharide-induced sepsis

To investigate the protective effect of cannabinoid receptor 2 (CB2) activation against acute lung injury in rats with lipopolysaccharide (LPS)-induced sepsis and explore the underlying mechanism. Forty-eight SD rats were randomly assigned into control group, model group, CB2 agonist group and P38 MAPK inhibitor group (n=12). In the latter 3 groups, the rats received intraperitoneal injection of LPS to induce sepsis, and the control rats were given saline injection. In CB2 agonist group, JWH133 (3 mg/kg) was injected intraperitoneally 30 min before LPS injection; in P38 MAPK inhibitor group, the rats received intraperitoneal injection of SB203580 (5 mg/kg) 30 min prior to JWH133 injection. The changes in lung histopathology, water content, fluid clearance rate, inflammatory factors, pulmonary expressions of CB2 and tight junctionrelated genes, and phosphorylation of P38 MAPK in the lung tissues were examined. The rat models of sepsis showed severe damage of alveolar structures with significantly decreased fluid clearance rate, lowered pulmonary expressions of CB2, occludin and ZO-1 mRNA and proteins, increased water content in the lung tissue, and increased phosphorylation level of P38 MAPK and TNF-α and IL-1β levels in lung lavage fluid (all P < 0.05). Treatment with JWH133 improved alveolar pathology in the septic rats, but there was still inflammatory infiltration; lung tissue water content, phosphorylation of P38 MAPK, and TNF-α and IL-1β levels in lung lavage fluid were all significantly decreased, and the fluid clearance rate, pulmonary expressions of CB2, occludin and ZO-1 were significantly increased (all P < 0.05). Additional treatment with SB203580 resulted in further improvements of alveolar pathologies, lowered phosphorylation levels of P38 MAPK in the lung tissue and TNF-α and IL-1β levels in lung lavage fluid, and increased the protein expressions of occludin and ZO-1 (P < 0.05) without causing significant changes in mRNA and protein expression of CB2 (P > 0.05). In rats with LPS-induced sepsis, activation of CB2 can inhibit the p38 MAPK signaling pathway, reduce the release of inflammatory factors in the lung tissues, promote tight junction protein expressions, and thus offer protection against acute lung injury.

Adjunctive therapy with the Tie2 agonist Vasculotide reduces pulmonary permeability in Streptococcus pneumoniae infected and mechanically ventilated mice

Community acquired pneumonia, mainly caused by Streptococcus pneumoniae (S.pn.), is a common cause of death worldwide. Despite adequate antibiotic therapy, pneumococcal pneumonia can induce pulmonary endothelial hyperpermeability leading to acute lung injury, which often requires mechanical ventilation (MV) causing ventilator-induced lung injury (VILI). Endothelial stabilization is mediated by angiopoietin-1 induced Tie2 activation. PEGylated (polyethylene glycol) Tie2-agonist Vasculotide (VT) mimics Angiopietin-1 effects. Recently, VT has been shown to reduce pulmonary hyperpermeability in murine pneumococcal pneumonia. The aim of this study was to determine whether VT reduces lung damage in S.pn. infected and mechanically ventilated mice. Pulmonary hyperpermeability, immune response and bacterial load were quantified in S.pn. infected mice treated with Ampicillin + /−VT and undergoing six hours of MV 24 h post infection. Histopathological lung changes, Tie2-expression and -phosphorylation were evaluated. VT did not alter immune response or bacterial burden, but interestingly combination treatment with ampicillin significantly reduced pulmonary hyperpermeability, histological lung damage and edema formation. Tie2-mRNA expression was reduced by S.pn. infection and/or MV but not restored by VT. Moreover, Tie2 phosphorylation was not affected by VT. These findings indicate that VT may be a promising adjunctive treatment option for prevention of VILI in severe pneumococcal pneumonia.

Taurine mitigates the development of pulmonary inflammation, oxidative stress, and histopathological alterations in a rat model of bile duct ligation.

Lung injury is a significant complication associated with cholestasis/cirrhosis. This problem significantly increases the risk of cirrhosis-related morbidity and mortality. Hence, finding effective therapeutic options in this field has significant clinical value. Severe inflammation and oxidative stress are involved in the mechanism of cirrhosis-induced lung injury. Taurine (TAU) is an abundant amino acid with substantial anti-inflammatory and antioxidative properties. The current study was designed to evaluate the role of TAU in cholestasis-related lung injury. For this purpose, bile duct ligated (BDL) rats were treated with TAU (0.5 and 1% w: v in drinking water). Significant increases in the broncho-alveolar lavage fluid (BALF) level of inflammatory cells (lymphocytes, neutrophils, basophils, monocytes, and eosinophils), increased IgG, and TNF-α were detected in the BDL animals (14 and 28days after the BDL surgery). Alveolar congestion, hemorrhage, and fibrosis were the dominant pulmonary histopathological changes in the BDL group. Significant increases in the pulmonary tissue biomarkers of oxidative stress, including reactive oxygen species formation, lipid peroxidation, increased oxidized glutathione levels, and decreased reduced glutathione, were also detected in the BDL rats. Moreover, significant myeloperoxidase activity and nitric oxide levels were seen in the lung of BDL rats. It was found that TAU significantly blunted inflammation, alleviated oxidative stress, and mitigated lung histopathological changes in BDL animals. These data suggest TAU as a potential protective agent against cholestasis/cirrhosis-related lung injury.

Inflammatory and proapoptotic effects of inhaling gasoline fumes on the lung and ameliorative effects of fenugreek seeds

Impacts of inhaling gasoline fumes on the lungs of adult male rats and the alleviating role of fenugreek seeds were evaluated. Twenty-four rats were divided into four groups, unexposed control and fenugreek groups, gasoline exposed groups for 6 h/6 day/week for 10 weeks with and without supplementation of fenugreek seed powder in food (5% w/w). Rats exposed to gasoline fumes showed significant elevation in lung tumor necrosis factor-α, as an inflammatory marker, and the proapoptotic marker Bax with a reduction in the antiapoptotic marker Bcl2. Moreover, remarkable elevations in transforming growth factor-β1, collagen and hydroxyproline were observed as fibrotic markers. Lung oxidative stress markers (hydrogen peroxides, malondialdehyde, and protein carbonyl) increased significantly along with marked decrease in total antioxidant capacity, superoxide dismutase, and catalase levels. Additionally, marked decreases in white and red blood cell counts, hemoglobin content, platelet count, accompanied by elevated red cell distribution width percentage were observed, supporting the inflammatory status. Histopathological changes represented by hematoxylin&eosin, immunohistochemistry staining for Bax&Bcl2, and transmission electron microscopy supported the negative impacts of gasoline fumes compared to the control group. Fenugreek seeds supplementation with gasoline exposure showed pronounced alleviation of lung biochemical and histopathological changes compared to the gasoline-exposed group.

Protective effects of fargesin on cadmium-induced lung injury through regulating aryl hydrocarbon receptor.

Fragesin, a traditional Chinese medicine, has been shown to exert anti-inflammatory effect. The aim of this study was to figure out the possible effectiveness of the fargesin, and to invest the mechanisms by which it works in the cadmium-induced lung injury in mice. Fargesin was given 1 h before cadmium treatment for 7 days. Then, the bronchoalveolar lavage fluid (BALF) were harvested to test inflammatory cells and pro-inflammatory cytokine production. Lung histopathological changes, myeloperoxidase (MPO) activity, and aryl hydrocarbon receptor (AhR) and nuclear factor kappa B (NF-κB) activation were measured. Fargesin dose-dependently reduced inflammatory cells and pro-inflammatory cytokines in BALF, improved lung histopathological injury, and inhibited lung wet/dry ratio and MPO activity. Furthermore, fargesin inhibited cadmium-induced NF-κB activation. In addition, fargesin was found to increase AhR expression. In conclusion, fargesin attenuates cadmium-induced lung injury may be via activating AhR, which subsequently suppressing the inflammatory response.

Total terpenoids of Inula japonica activated the Nrf2 receptor to alleviate the inflammation and oxidative stress in LPS-induced acute lung injury

BackgroundAcute lung injury (ALI) is a life-threatening lung disease and characterized by pulmonary edema and atelectasis. Inula japonica Thunb. is a commonly used traditional Chinese medicine for the treatment of lung diseases. However, the potential effect and mechanism of total terpenoids of I. japonica (TTIJ) on ALI remain obscure. PurposeThis study focused on the protective effect of TTIJ on lipopolysaccharide (LPS)-induced ALI in mice and its potential mechanism. Study design and methodsA mouse model of ALI was established by intratracheal instillation of LPS to investigate the protective effect of TTIJ. RNA-seq and bioinformatics were then performed to reveal the underlying mechanism. Finally, western blot and real-time qPCR were used to verify the effects of TTIJ on the inflammation and oxidative stress. ResultsTTIJ notably attenuated LPS-induced histopathological changes of lung. The RNA-seq result suggested that the protective effect of TTIJ on LPS-induced ALI were associated with the Toll-like receptor 4 (TLR4) and nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathways. Pretreatment with TTIJ significantly reduced the inflammation and oxidative stress via regulating levels of pro-inflammatory and anti-oxidative cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione (GSH), in LPS-induced ALI mice. TTIJ treatment could suppress the cyclooxygenase-2 (COX-2) expression level and the phosphorylation of p65, p38, ERK, and JNK through the inactivation of the MAPK/NF-κB signaling pathway in a TLR4-independent manner. Meanwhile, TTIJ treatment upregulated expression levels of proteins involved in the Nrf2 signaling pathway, such as heme oxygenase-1 (HO-1), NAD(P)H: quinoneoxidoreductase-1 (NQO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM), via activating the Nrf2 receptor, which was confirmed by the luciferase assay. ConclusionTTIJ could activate the Nrf2 receptor to alleviate the inflammatory response and oxidative stress in LPS-induced ALI mice, which suggested that TTIJ could serve as the potential agent in the treatment of ALI.

Baicalin Ameliorates Radiation-Induced Lung Injury by Inhibiting the CysLTs/CysLT1 Signaling Pathway.

Objective Radiation-induced lung injury (RILI) is a common complication of radiotherapy for thoracic tumors. This study investigated the alleviating effect of baicalin (BA) on RILI and its possible mechanism. Methods RILI model was established by chest irradiation (IR) of C57BL/6 mice for 16 weeks. Different concentrations of BA were administered, and dexamethasone (DXM) was used as a positive control. Then, the lung pathological changes were observed by HE and Masson staining. The levels of TGF-β, TNF-α, IL-1β, IL-6, CysLT, LTC4, and LTE4 were measured by ELISA. The CysLT1 expression was detected by qPCR, immunohistochemistry, and western blot. Type II AEC cells were pretreated with LTD-4 to establish the RILI cell model and intervened with different concentrations of BA. Then, the collagen I protein level was measured by ELISA. The CysLT1 and α-SMA expression were detected by qPCR, immunofluorescence, and western blot. Results BA could effectively improve lung histopathological changes and pulmonary fibrosis. In vivo, BA could inhibit the levels of TGF-β, TNF-α, IL-1β, and IL-6 and reduce the levels of CysLT, LTC4, and LTE4. In vitro, different concentrations of LTD4 could reduce the viability of type II AEC cells, which could be reversed by the administration of different concentrations of BA. In addition, BA could reduce CysLT1 mRNA, as well as CysLT1 and α-SMA protein levels in vitro and in vivo. Conclusion BA attenuated lung inflammation and pulmonary fibrosis by inhibiting the CysLTs/CysLT1 pathway, thereby protecting against RILI.

Gut Microbiota Protected Against pseudomonas aeruginosa Pneumonia via Restoring Treg/Th17 Balance and Metabolism.

Backgrounds and PurposeThe theory of “entero-pulmonary axis” proves that pneumonia leads to gut microbiota disturbance and Treg/Th17 immune imbalance. This study is aimed to explore the potential mechanism of fecal microbiota transplantation (FMT) in the treatment of Pseudomonas aeruginosa pneumonia, in order to provide new insights into the treatment of pneumonia.Methods Pseudomonas aeruginosa and C57/BL6 mice were used to construct the acute pneumonia mouse model, and FMT was treated. Histopathological changes in lung and spleen were observed by HE staining. The expression of CD25, Foxp3 and IL-17 was observed by immunofluorescence. The proportion of Treg and Th17 cells was analyzed by flow cytometry. Serum IL-6, LPS, and IFN-γ levels were detected by ELISA. The expression of TNF-α, IFN-γ, IL-6, IL-2, Foxp3, IL-17, IL-10, and TGFβ1 in lung tissue homogenate was detected by qRT-PCR. 16S rRNA sequencing and non-targeted metabolomics were used to analyze gut microbiota and metabolism.Results Pseudomonas aeruginosa caused the decrease of body weight, food and water intake, lung tissue, and spleen injury in mice with pneumonia. Meanwhile, it caused lung tissue and serum inflammation, and Treg/Th17 cell imbalance in mice with pneumonia. Pseudomonas aeruginosa reduced the diversity and number of gut microbiota in pneumonia mice, resulting in metabolic disorders, superpathway of quinolone and alkylquinolone biosynthesis. It also led to the decrease of 2-heptyl-3-hydroxy-4(1H)-quinolone biosynthesis, and the enrichment of Amino sugar and nucleotide sugar metabolism. FMT with or without antibiotic intervention restored gut microbiota abundance and diversity, suppressed inflammation and tissue damage, and promoted an immunological balance of Treg/Th17 cells in mice with pneumonia. In addition, FMT inhibited the aerobactin biosynthesis, 4-hydroxyphenylacetate degradation, superpathway of lipopolysaccharide biosynthesis and L-arabinose degradation IV function of microbiota, and improved amino sugar and nucleotide sugar metabolism.ConclusionsFMT restored the Treg/Th17 cells’ balance and improved inflammation and lung injury in mice with Pseudomonas aeruginosa pneumonia by regulating gut microbiota disturbance and metabolic disorder.

Histological Changes in the Lung Tissue in Association with COVID-19: Review Article

Background: It has been shown that SARS-CoV-2 is a multi-systemic virus and can affect number of body systems including the respiratory tract, the gastro-intestinal tract, the liver, the kidney and the nervous system. Despite the high mortality rate, there is little literature on postmortem findings of this unique virus, perhaps due to its highly contagious nature, inadequate information on prevention, and a lack of robust infrastructure for appropriate management of infected cases at various centers throughout the world. Aim of the study: The aim of the current study was to review and list the main histological changes seen in patients died because of COVID-19. Methods: A systemic search was carried out including Google Scholar, PubMed, and MEDLINE and the Google search Engine in order to scan all available published articles dealing with histological changes affection the lung in patients with documented COVID-19. The following key words were used to accomplish the search mission: COVID-19, SARS-CoV-2, Lung Histology, Pulmonary Histology, Histopathology. The search was limited to articles written in English language. Any article published between the end of 2019 and the time of initiating the current work was reviewed. The information in the current review is totally based on reviewed articles that are mentioned in the section of references. Results: The main sources of lung tissues were Whole lung biopsy, Postmortem study, Core needle biopsy and Ultrasound based samples from autopsy. The exudative changes include injury to pneumocytes, congestion of capillaries, giant cell formations, dilation of alveolar ducts, thickening of capillaries, edema of interstitium and formation of hyaline membrane. The proliferative changes include hyperplasia of Type-2 pneumocytes with some reactive atypia with proliferation of myofibroblastic cells leading to granulation tissue formation, thickening of alveolar wall accumulation of alveolar macrophages, interstitial thickening which harbors collections of proliferating fibroblasts together with foci of hemorrhage and lymphocytic infiltration. Conclusion: The main histopathological changes in lung of patients with COVID-19 can be grouped into three main phases, exudative, proliferative and fibrotic phases in addition to changes involving vascular tissues, bronchi and bronchioles and the main changes are the diffuse alveolar damage seen in exudative and proliferative phases.

The Alleviation of LPS-Induced Murine Acute Lung Injury by GSH-Mediated PEGylated Artesunate Prodrugs.

Acute lung injury (ALI) or its aggravated stage acute respiratory distress syndrome (ARDS) is a common severe clinical syndrome in intensive care unit, may lead to a life-threatening form of respiratory failure, resulting in high mortality up to 30–40% in most studies. Nanotechnology-mediated anti-inflammatory therapy is an emerging novel strategy for the treatment of ALI, has been demonstrated with unique advantages in solving the dilemma of ALI drug therapy. Artesunate (ART), a derivative of artemisinin, has been reported to have anti-inflammatory effects. Therefore, in the present study, we designed and synthesized PEGylated ART prodrugs and assessed whether ART prodrugs could attenuate lipopolysaccharide (LPS) induced ALI in vitro and in vivo. All treatment groups were conditioned with ART prodrugs 1 h before challenge with LPS. Significant increased inflammatory cytokines production and decreased GSH levels were observed in the LPS stimulated mouse macrophage cell line RAW264.7. Lung histopathological changes, lung W/D ratio, MPO activity and total neutrophil counts were increased in the LPS-induced murine model of ALI via nasal administration. However, these results can be reversed to some extent by treatment of ART prodrugs. The effectiveness of mPEG2k-SS-ART in inhibition of ALI induced by LPS was confirmed. In conclusion, our results demonstrated that the ART prodrugs could attenuate LPS-induced ALI effectively, and mPEG2k-SS-ART may serve as a novel strategy for treatment of inflammation induced lung injury.

Small Extracellular Vesicles Containing miR-34c Derived from Bone Marrow Mesenchymal Stem Cells Regulates Epithelial Sodium Channel via Targeting MARCKS.

Epithelial sodium channel (ENaC) is a pivotal regulator of alveolar fluid clearance in the airway epithelium and plays a key role in the treatment of acute lung injury (ALI), which is mainly composed of the three homologous subunits (α, β and γ). The mechanisms of microRNAs in small extracellular vesicles (sEVs) derived from mesenchymal stem cell (MSC-sEVs) on the regulation of lung ion transport are seldom reported. In this study, we aimed at investigating whether miR-34c had an effect on ENaC dysfunction induced by lipopolysaccharide and explored the underlying mechanism in this process. Primarily, the effect of miR-34c on lung edema and histopathology changes in an ALI mouse model was investigated. Then the uptake of PKH26-labeled sEVs was observed in recipient cells, and we observed that the overexpression of miR-34c in MSC-sEVs could upregulate the LPS-inhibited γ-ENaC expression. The dual luciferase reporter gene assay demonstrated that myristoylated alanine-rich C kinase substrate (MARCKS) was one of target genes of miR-34c, the protein expression of which was negatively correlated with miR-34c. Subsequently, either upregulating miR-34c or knocking down MARCKS could increase the protein expression of phospho-phosphatidylinositol 3-kinase (p-PI3K) and phospho-protein kinase B (p-AKT), implying a downstream regulation pathway was involved. All of the above suggest that miR-34c in MSC-sEVs can attenuate edematous lung injury via enhancing γ-ENaC expression, at least partially, through targeting MARCKS and activating the PI3K/AKT signaling pathway subsequently.

Punicalagin suppresses inflammation in ventilator-induced lung injury through protease-activated receptor-2 inhibition-induced inhibition of NLR family pyrin domain containing-3 inflammasome activation.

Punicalagin is recorded to be a potent anti-inflammatory drug, while its effect on inflammation existing in ventilator-induced lung injury (VILI) requires further verification. Rats were pretreated with punicalagin, followed by VILI modeling. Lung histopathological examination was performed with hematoxylin-eosin staining accompanied by the lung injury score. The lung wet/dry (W/D) weight ratio and total bronchoalveolar lavage fluid (BALF) protein level were measured. After transfection with protease-activated receptor-2 (PAR2) overexpression plasmids, mouse alveolar epithelial MLE-12 cells were treated with punicalagin and then subjected to cyclic stretching. Punicalagin's cytotoxicity to MLE-12 cells were measured by MTT assay. The levels of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6), PAR2, NLR family pyrin domain containing-3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC) in the BALF, lung tissues or cells were analyzed by enzyme-linked immune-sorbent assay (ELISA), qRT-PCR or/and western blot. Punicalagin treatment attenuated VILI-induced lung histopathological changes and counteracted VILI-induced increases in the lung injury score, W/D weight ratio and total protein level in BALF. Also, punicalagin treatment counteracted in vivo VILI/cyclic stretching-induced increases in the levels of PAR2, inflammatory cytokines, NLRP3, and ASC. PAR2 overexpression potentiated the cyclic stretching-induced effects, while punicalagin treatment revoked this PAR2 overexpression-induced potentiation effect. In turn, PAR2 overexpression partly resisted the punicalagin treatment-induced counteractive effects on the cyclic stretching-induced effects. Punicalagin suppresses inflammation in VILI through PAR2 inhibition-induced inhibition of NLRP3 inflammasome activation.

Arbutin Alleviates LPS Induced Sepsis Pneumonia in Mice.

The aim of this study was to investigate the effects of arbutin (AR) on lipopolysaccharide (LPS)-induced sepsis pneumonia. LPS-induced mice and A549 cells were used to establish septic pneumonia model. AR significantly decreased lung wet-to-dry weight (W/D) ratio, lung myeloperoxidase (MPO) activity and ameliorated lung histopathological changes. In addition, AR increased super oxide dismutase (SOD) activity, decreased malondialdehyde (MDA) content and levels of cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-β) and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) in mice. Furthermore, the results demonstrated that AR inhibited the JAK2/STAT3/NF-κB pathway in LPS-induced A549 cells which was further confirmed by siRNA JAK2 experiment. The experimental results indicated that the protective mechanism of AR on sepsis pneumonia might be attributed partly to the inhibition of cytokine production and JAK2/STAT3/NF-κB pathway.

Effect of Houpo-Mahuang Decoction on aggravated asthma induced by cigarette smoke and the expression of TRPA1 and tight junctions in mice

Ethnopharmacological relevanceCigarette smoke (CS) is a common environmental irritant and a risk factor for asthma, as it induces as well as aggravates asthmatic attacks. The injured airway epithelial tight junctions (TJs) aggravate asthma. CS can aggravate asthma by activating the transient receptor potential ankyrin A1 (TRPA1) channel and enhancing TJs destruction. Houpo Mahuang decoction (HPMHD) is a classic traditional Chinese prescription for the treatment of asthma. However, its underlying action mechanism is unclear. Aim of the studyThe present study aimed to evaluate the effect of HPMHD on the asthma phenotype and the regulation of TRPA1 and TJs in a CS-induced mouse model of aggravated asthma. Materials and methodsUnder optimized chromatographic and mass spectrometry conditions, the ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) technique was used to detect and analyze the major chemical components of HPMHD. C57BL/6 female mice were randomly divided into seven groups, viz, normal saline (NS) group, ovalbumin (OVA) + CS group, dexamethasone group, HPMHD high-dose group and low-dose groups, n-butanol extract group, and ethyl acetate extract group, with 10 mice in each group. OVA sensitization and challenge, and CS exposure were used to establish the aggravated asthma model. As the main indices to evaluate the protective effect of HPMHD, the eosinophils count in peripheral blood, percentages of inflammatory cells classified and the levels of interleukin (IL)-4, IL-5, IL-13 in the bronchoalveolar lavage fluid (BALF), airway responsiveness enhanced pause (Penh), and changes in lung histopathology were determined and compared among the groups. The mRNA and protein expression of TRPA1 and TJs in lung tissue was also examined. ResultsUsing UPLC-QTOF-MS, the chemical components of HPMHD, including ephedrine, pseudoephedrine, laetrile, and amygdalin amide, were identified by 51 signal peaks. Compared with those in the NS group, the eosinophil number in the peripheral blood and the eosinophils and neutrophils percentages in BALF of the OVA + CS group were remarkably increased. Following the inhalation of 50 μl of acetylcholine chloride (ACH) at doses of 25 and 50 mg/mL, the Penh increased significantly (p < 0.01). Moreover, in the OVA + CS group, hematoxylin and eosin (H&E) staining of lung tissue showed a significant number of infiltrated inflammatory cells, increased mucus secretion in the lumen, damaged bronchial mucosa, increased thickness of tracheal wall, and increased score of lung damage (p < 0.01). The IL-4/5/13 levels were also remarkably increased (p < 0.01). The protein as well as gene expression of both ZO-1 and occludin decreased markedly in the lung tissue, while the expression of TRPA1 and claudin-2 was increased (p < 0.05, p < 0.01). Next, the OVA + CS group and the treatment groups were compared. The inflammatory cells, Penh value, and levels of IL-4/5/13 were significantly reduced, and less lung injury was observed in the treatment groups. The gene and protein levels of TRPA1 and TJs were corrected (p < 0.05, p < 0.01); the effects on the HPMHD high-dose and ethyl acetate extract groups were particularly remarkable. ConclusionsHPMHD reduced airway hyperresponsiveness, inflammatory cell recruitment and Th2 cytokine secretion in CS-induced aggravated asthma mice, in a manner potentially dependent on regulation of the expression of TRPA1 and TJ proteins. Both the n-butanol and ethyl acetate extracts contained the active ingredients, especially the ethyl acetate extract.