Evaluation of oxidative stress biomarkers in idiopathic pulmonary fibrosis and therapeutic applications: a systematic review

Complications and comorbidities associated with antineoplastic chemotherapy: Rethinking drug design and delivery for anticancer therapy

Despite the considerable advancements in chemotherapy as a cornerstone modality in cancer treatment, the prevalence of complications and pre-existing diseases is on the rise among cancer patients along with prolonged survival and aging population. The relationships between these disorders and cancer are intricate, bearing significant influence on the survival and quality of life of individuals with cancer and presenting challenges for the prognosis and outcomes of malignancies. Herein, we review the prevailing complications and comorbidities that often accompany chemotherapy and summarize the lessons to learn from inadequate research and management of this scenario, with an emphasis on possible strategies for reducing potential complications and alleviating comorbidities, as well as an overview of current preclinical cancer models and practical advice for establishing bio-faithful preclinical models in such complex context.

Functional crosstalk between angiotensin receptors (types 1 and 2) and relaxin family peptide receptor 1 (RXFP1): Implications for the therapeutic targeting of fibrosis

Class A, rhodopsin-like, G-protein-coupled receptors (GPCRs) are by far the largest class of GPCRs and are integral membrane proteins used by various cells to convert extracellular signals into intracellular responses. Initially, class A GPCRs were believed to function as monomers, but a growing body of evidence has emerged to suggest that these receptors can function as homodimers and heterodimers and can undergo functional crosstalk to influence the actions of agonists or antagonists acting at each receptor. This review will focus on the angiotensin type 1 (AT1) and type 2 (AT2) receptors, as well as the relaxin family peptide receptor 1 (RXFP1), each of which have their unique characteristics but have been demonstrated to undergo some level of interaction when appropriately co-expressed, which influences the function of each receptor. In particular, this receptor functional crosstalk will be discussed in the context of fibrosis, the tissue scarring that results from a failed wound-healing response to injury, and which is a hallmark of chronic disease and related organ dysfunction. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Protective effects of E-CG-01 (3,4-lacto cycloastragenol) against bleomycin-induced lung fibrosis in C57BL/6 mice

Idiopathic pulmonary fibrosis is an aging-related, chronic lung disease, with unclear pathogenesis and no effective treatment. One of the triggering factors in cell aging is oxidative stress and it is known to have a role in idiopathic pulmonary fibrosis. In this paper, the protective effect of the E-CG-01 (3,4-lacto-cycloastragenol) molecule in terms of its antioxidant properties was evaluated in the bleomycin induced mice lung fibrosis model. Bleomycin sulfate was administered as a single dose (2.5 U/kg body weight) intratracheally to induce lung fibrosis. E-CG-01 was administered intraperitoneally in three different doses (2 mg/kg/day, 6 mg/kg/day, and 10 mg/kg/day) for 14 days, starting three days before the bleomycin administration. Fibrosis was examined by Hematoxylin-Eosin, Masson Trichrome, and immunohistochemical staining for TGF-beta1, Type I collagen Ki-67, and gama-H2AX markers. Activity analysis of catalase and Superoxide dismutase enzymes, measurement of total oxidant, total glutathione, and Malondialdehyde levels. In histological analysis, it was determined that all three different doses of the molecule provided a prophylactic effect against the progression of fibrosis compared to the bleomycin control group. However, it was observed that only the molecule applied in the high dose decreased the total oxidant stress level. Lung weight ratio increased in the BLM group but significantly reduced with high-dose E-CG-01. E-CG-01 at all doses reduced collagen deposition, TGF-β expression, and Ki-67 expression compared to the BLM group. Intermediate and high doses of E-CG-01 also significantly reduced alveolar wall thickness and edema formation. These findings suggest that E-CG-01 has potential therapeutic effects in mitigating lung fibrosis through its antioxidant properties.

Emerging roles of ferroptosis in pulmonary fibrosis: current perspectives, opportunities and challenges

Pulmonary fibrosis (PF) is a chronic interstitial lung disorder characterized by abnormal myofibroblast activation, accumulation of extracellular matrix (ECM), and thickening of fibrotic alveolar walls, resulting in deteriorated lung function. PF is initiated by dysregulated wound healing processes triggered by factors such as excessive inflammation, oxidative stress, and coronavirus disease (COVID-19). Despite advancements in understanding the disease's pathogenesis, effective preventive and therapeutic interventions are currently lacking. Ferroptosis, an iron-dependent regulated cell death (RCD) mechanism involving lipid peroxidation and glutathione (GSH) depletion, exhibits unique features distinct from other RCD forms (e.g., apoptosis, necrosis, and pyroptosis). Imbalance between reactive oxygen species (ROS) production and detoxification leads to ferroptosis, causing cellular dysfunction through lipid peroxidation, protein modifications, and DNA damage. Emerging evidence points to the crucial role of ferroptosis in PF progression, driving macrophage polarization, fibroblast proliferation, and ECM deposition, ultimately contributing to alveolar cell death and lung tissue scarring. This review provides a comprehensive overview of the latest findings on the involvement and signaling mechanisms of ferroptosis in PF pathogenesis, emphasizing potential novel anti-fibrotic therapeutic approaches targeting ferroptosis for PF management.

Therapeutic potential of salvigenin to combat atrazine induced liver toxicity in rats via regulating Nrf-2/Keap-1 and NF-κB pathway

Atrazine (ATR) is the second most extensively used herbicide which adversely affects the body organs including liver. Salvigenin (SGN) is a flavonoid which demonstrates a wide range of biological and pharmacological abilities. This study was planned to assess the protective ability of SGN to avert ATR induced liver damage in rats. Thirty-two rats (Rattus norvegicus) were divided into four groups including control, ATR (5 mg/kg), ATR (5 mg/kg) + SGN (10 mg/kg) and SGN (10 mg/kg) alone supplemented group. ATR exposure reduced the expression of Nrf-2 while instigating an upregulation in Keap-1 expression. Furthermore, the activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), heme‑oxygenase-1 (HO-1) and glutathione reductase (GSR) contents were decreased while increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels after ATR treatment. Moreover, ATR poisoning increased the levels of ALT, AST, and ALP while reducing the levels of total proteins, and albumin in hepatic tissues of rats. Besides, ATR administration escalated the expressions of Bax and Caspase-3 while inducing a downregulation in the expressions of Bcl-2. Similarly, ATR intoxication increased the levels of Interleukin-6 (IL-6), Nuclear factor kappa-B (NF-κB), Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and the activity of cyclooxygenase-2 (COX-2). Furthermore, ATR disrupted the normal histology of hepatic tissues. However, SGN treatment remarkably protected the liver tissues via regulating antioxidant, anti, inflammatory, anti-apoptotic as well as histology parameters. Therefore, it is concluded that SGN can be used as therapeutic agent to combat ATR-induced hepatotoxicity.

Inhibition of SMYD2 attenuates paraquat-induced pulmonary fibrosis by inhibiting the epithelial-mesenchymal transition through the GLIPR2/ERK/p38 axis

Paraquat (PQ) poisoning leads to irreversible fibrosis in the lungs with high mortality and no known antidote. In this study, we investigated the effect of the SET and MYND domain containing 2 (SMYD2) on PQ-induced pulmonary fibrosis (PF) and its potential mechanisms. We established an in vivo PQ-induced PF mouse model by intraperitoneal injection of PQ (20 mg/kg) and in vitro PQ (25 μM)-injured MLE-12 cell model. On the 15th day of administration, tissue injury, inflammation, and fibrosis in mice were evaluated using various methods including routine blood counts, blood biochemistry, blood gas analysis, western blotting, H&E staining, ELISA, Masson staining, and immunofluorescence. The findings indicated that AZ505 administration mitigated tissue damage, inflammation, and collagen deposition in PQ-poisoned mice. Mechanistically, both in vivo and in vitro experiments revealed that AZ505 treatment suppressed the PQ-induced epithelial-mesenchymal transition (EMT) process by downregulating GLI pathogenesis related 2 (GLIPR2) and ERK/p38 pathway. Further investigations demonstrated that SMYD2 inhibition decreased GLIPR2 methylation and facilitated GLIPR2 ubiquitination, leading to GLIPR2 destabilization in PQ-exposed MLE-12 cells. Moreover, rescue experiments conducted in vitro demonstrated that GLIPR2 overexpression eliminated the inhibitory effect of AZ505 on the ERK/p38 pathway and EMT. Our results reveal that the SMYD2 inhibitor AZ505 may act as a novel therapeutic candidate to suppress the EMT process by modulating the GLIPR2/ERK/p38 axis in PQ-induced PF.

Acetaldehyde Dehydrogenase 2 Deficiency Aggravates Lung Fibrosis through Mitochondrial Dysfunction and Aging in Fibroblasts

Idiopathic pulmonary fibrosis, a fatal interstitial lung disease, is characterized by fibroblast activation and aberrant extracellular matrix accumulation. Effective therapeutic development is limited because of incomplete understanding of the mechanisms by which fibroblasts become aberrantly activated. Here, we show acetaldehyde dehydrogenase 2 (ALDH2) in fibroblasts as a potential therapeutic target for pulmonary fibrosis. A decrease in ALDH2 expression was observed in patients with idiopathic pulmonary fibrosis and bleomycin-treated mice. ALDH2 deficiency spontaneously induces collagen accumulation in the lungs of aged mice. Furthermore, young ALDH2 knockout mice exhibited exacerbated bleomycin-induced pulmonary fibrosis and increased mortality compared with that in control mice. Mechanistic studies revealed that transforming growth factor (TGF)-β1 induction and ALDH2 depletion constitute a positive feedback loop that exacerbates fibroblast activation. TGF-β1 down-regulated ALDH2 through a TGF-β receptor 1/Smad3-dependent mechanism. The subsequent deficiency in ALDH2 resulted in fibroblast dysfunction that manifested as impaired mitochondrial autophagy and senescence, leading to fibroblast activation and extracellular matrix production. ALDH2 overexpression markedly suppressed fibroblast activation, and this effect was abrogated by PTEN-induced putative kinase 1 (PINK1) knockdown, indicating that the profibrotic effects of ALDH2 are PINK1- dependent. Furthermore, Alda-1-induced ALDH2 activation reversed the established pulmonary fibrosis in both young and aged mice. In conclusion, ALDH2 expression inhibits the pathogenesis of pulmonary fibrosis. Strategies to up-regulate or activate ALDH2 expression could be potential therapies for pulmonary fibrosis.

A Chinese classical prescription Maimendong decoction in treatment of pulmonary fibrosis: an overview

Pulmonary fibrosis (PF) is a chronic and progressive disease characterized by fibrosis and interstitial pneumonia. It has similar clinical symptoms to "Fei Bi" and "Fei Wei" as described in the traditional Chinese medicine (TCM) classic Jingui Yaolue written by Zhang Zhongjing in the Han Dynasty. This study explored the potential of Maimendong Decoction (MMDD). MMDD consists of Ophiopogon japonicus (L.f) (ophiopogonis), Pinellia ternata (Thunb.) Breit. (pinellia), Panax ginseng C. A. Mey. (ginseng), Glycyrrhiza uralensis Fisch. (glycyrrhiza), Zizi phus jujuba Mill. (jujuba), and Oryza sativa L. (oryza sativa), with the function of nourishing the lung and stomach, and reducing the effect of reverse qi. It has been used clinically for over two thousand years to treat conditions like "Fei Bi" and "Fei Wei". Previous research suggests that MMDD and its individual herbal extracts have anti-fibrotic effects. The main focus of MMDD in treating PF is to reduce inflammatory cytokines, inhibit pro-fibrotic factors and oxidative stress, promote differentiation and homing of bone marrow mesenchymal stem cells, and enhance cell autophagy activity. This review summarized the clinical applications, mechanisms, and pharmacological effects of MMDD in treating PF based on existing clinical applications and experimental research. It also discussed current issues and prospects, aiming to provide a reference for further research on the mechanism of PF, drug development, and clinical trials.

Co-Delivery of Astaxanthin and siTGF-β1 via Ionizable Liposome Nanoparticles for Improved Idiopathic Pulmonary Fibrosis Therapy

Alleviating the injury of type II alveolar epithelial cells (AEC 2s) and inhibiting the activation and differentiation of fibroblasts are significant for improving the therapeutic effect of idiopathic pulmonary fibrosis (IPF). To this aim, ionizable liposome nanoparticles (ASNPs) coloaded with antioxidant drug astaxanthin (AST) and small interfering RNA targeting transforming growth factor β1 (siTGF-β1) were developed for enhanced IPF therapy. ASNPs showed high loading and intracellular delivery efficiency for AST and siTGF-β1. After the injection of ASNPs in an IPF mice model, the loaded AST largely scavenged reactive oxygen species (ROS) in the diseased lung to reduce AEC2 apoptosis, thereby ensuring the integrity of the alveolar epithelium. Meanwhile, siTGF-β1, delivered by ASNPs, significantly silenced the expression of TGF-β1 in fibroblasts, inhibiting the differentiation of fibroblasts into myofibroblasts as well as reducing the excessive deposition of extracellular matrix (ECM). The combined use of the two drugs exhibited an excellent synergistic antifibrotic effect and was conducive to minimizing alveolar epithelial damage. This work provides a codelivery strategy of AST and siTGF-β1, which shows great promise for the treatment of IPF by simultaneously reducing alveolar epithelial damage and inhibiting fibroblast activation.

Unraveling the interplay between vital organelle stress and oxidative stress in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease characterized by excessive accumulation of extracellular matrix, leading to irreversible fibrosis. Emerging evidence suggests that endoplasmic reticulum (ER) stress, mitochondrial stress, and oxidative stress pathways play crucial roles in the pathogenesis of IPF. ER stress occurs when the protein folding capacity of the ER is overwhelmed, triggering the unfolded protein response (UPR) and contributing to protein misfolding and cellular stress in IPF. Concurrently, mitochondrial dysfunction involving dysregulation of key regulators, including PTEN-induced putative kinase 1 (PINK1), Parkin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and sirtuin 3 (SIRT3), disrupts mitochondrial homeostasis and impairs cellular energy metabolism. This leads to increased reactive oxygen species (ROS) production, release of pro-fibrotic mediators, and activation of fibrotic pathways, exacerbating IPF progression. The UPR-induced ER stress further disrupts mitochondrial metabolism, resulting in altered mitochondrial mechanisms that increase the generation of ROS, resulting in further ER stress, creating a feedback loop that contributes to the progression of IPF. Oxidative stress also plays a pivotal role in IPF, as ROS-mediated activation of TGF-β, NF-κB, and MAPK pathways promotes inflammation and fibrotic responses. This review mainly focuses on the links between ER stress, mitochondrial dysfunctions, and oxidative stress with different signaling pathways involved in IPF. Understanding these mechanisms and targeting key molecules within these pathways may offer promising avenues for intervention.

Phœnix dactylifera, L. seed oil alleviates Bleomycin-induced pulmonary fibrosis and oxidative stress in Wistar rats

OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) is the most serious form of interstitial lung disease. We aimed to investigate the effect of Phœnix dactylifera, L. seed oil (DSO) on a murine model of IPF induced by bleomycin (BLM).

METHODS

Male Wistar rats were treated with a single intra-tracheal injection of BLM (4 mg/kg) and a daily intraperitoneal injection of DSO (75, 150 and 300 mg/kg) for 4 weeks.

RESULTS

Our phytochemical results showed that DSO has an important antioxidant activity with a high content of polyphenols and flavonoids. High-Performance Liquid Chromatography (HPLC) and Gas chromatography/mass spectrometry (GC-MS) analysis revealed a high amount of oleic and lauric acids and a large quantity of vitamins. Histological examination showed a significant reduction in fibrosis score and collagen bands in the group of rats treated with 75 mg/kg of DSO compared to the BLM group. DSO (75 mg/kg) reversed also the increase in catalase and malondialdehyde (MDA) levels while higher doses (150 and 300 mg/kg) are ineffective against the deleterious effects of BLM. We revealed also that DSO has no renal or hepatic cytotoxic effects.

CONCLUSION

DSO can play antioxidant and antifibrotic effects on rat models of pulmonary fibrosis at the lowest dose administered.

Curative effects of tectochrysin on paraquat-instigated testicular toxicity in rats: A biochemical and histopathological based study

Background

Paraquat (PQ) is a herbicide that is used globally in the agriculture sector to eradicate unwanted weeds, however it also induces significant damages in various organs of the body such as testes. Tectochrysin (TEC) is an important flavonoid that shows versatile therapeutic potentials. Currently, there is no established antidote to cure PQ-induced testicular toxicity.

Objective

The present study was conducted to evaluate the ameliorative effects of TEC against PQ prompted testicular damage.

Methods

Sprague-Dawley rats (n = 48) were used to conduct the trial. Rats were allocated in to 4 groups i.e., Control, PQ administrated group (5 mgkg-1), PQ + TEC co-administrated group (5 mgkg-1 + 2.5 mgkg-1) and TEC only administrated group (2.5 mgkg-1). The trial was conducted for 8 weeks. The activity of anti-oxidants and the levels of MDA and ROS were determined by spectrophotometric method. Steroidogenic enzymes as well as apoptotic markers expressions were evaluated by qRT-PCR. The level of hormones and inflammatory indices was quantified by enzyme-linked immunosorbent assay.

Results

PQ exposure markedly (P < 0.05) disturbed the biochemical, spermatogenic and histological profile in the rats. Nevertheless, TEC treatment considerably (P < 0.05) increased CAT, GPx GSR and SOD activity, besides decreasing MDA and ROS contents. TEC administration also increased sperm viability, count and motility. 17β-HSD, 3β-HSD, StAR and Bcl-2 expressions were also increased following TEC administration. The supplementation of TEC substantially (P < 0.05) decreased Bax, Caspase-3 expression and the levels of inflammatory markers i.e., interleukin-1β (IL-1β), interleukin-6 (IL-6), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) activity. Additionally, the levels of plasma testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were increased following TEC supplementation. Furthermore, TEC supplementation considerably decreased sperm structural abnormalities and histomorphological damages of the testes. The mitigative role of TEC might be due to its anti-inflammatory, anti-apoptotic, androgenic and anti-oxidant potentials.

Conclusion

Taken together, it is concluded that TEC can be used as a potential candidate to treat testicular toxicity.

Superoxide dismutase secreting Bacillus amyloliquefaciens spores attenuate pulmonary fibrosis

Superoxide dismutase (SOD) can convert active oxygen to oxygen or hydrogen peroxide, and recent research has suggested that it can protect against lung damage and fibrosis. Clinical applications based on SOD remain limited however due to costs and low stability. We here investigated a potential new therapeutic delivery system for this enzyme in the form of SOD-overexpressing Bacillus amyloliquefaciens spores which we introduced into a bleomycin-induced pulmonary fibrosis mouse model. This treatment significantly alleviated the disease, as quantified using a hydroxyproline assay, at 107 colony forming unit (CFU) of Bacillus spores per day. Exposure of the mice to the spores was further found to decrease the lung mRNA levels of CTGF, Col1a1, α-SMA, TGF-β, TNF-α, and IL-6, and the protein levels of TGF-β, Smad2/3, αSMA and Col1a1, all major indicators of pulmonary fibrosis. Survival benefits, and reduced byproducts of lipid peroxidase such as malondialdehyde and 4-hydroxynen, were also noted in the treated animals. The beneficial effects of these Bacillus spores on pulmonary fibrosis were further found to be greater than the equivalent free SOD concentration. Immunofluorescence staining of primary pulmonary fibroblasts extracted from the bleomycin-induced model showed decreased αSMA expression following the in vivo treatment with SOD-overexpressing Bacillus. Our treatment approach SOD through Bacillus spores shows beneficial effects against pulmonary fibrosis, combined with the suppression of the SMAD/TGF-β pathway, suggesting that it is an effective novel delivery route for antioxidants.

Disruption of extracellular redox balance drives persistent lung fibrosis and impairs fibrosis resolution

Lung fibrosis is a devastating outcome of various diffuse parenchymal lung diseases. Despite rigorous research efforts, the mechanisms that propagate its progressive and nonresolving nature remain enigmatic. Oxidative stress has been implicated in the pathogenesis of lung fibrosis. However, the role of extracellular redox state in disease progression and resolution remains largely unexplored. Here, we show that compartmentalized control over extracellular reactive oxygen species (ROS) by aerosolized delivery of recombinant extracellular superoxide dismutase (ECSOD) suppresses an established bleomycin-induced fibrotic process in mice. Further analysis of publicly available microarray, RNA-seq and single-cell RNAseq datasets reveals a significant decrease in ECSOD expression in fibrotic lung tissues that can be spontaneously restored during fibrosis resolution. Therefore, we investigate the effect of siRNA-mediated ECSOD depletion during the established fibrotic phase on the self-limiting nature of the bleomycin mouse model. Our results demonstrate that in vivo knockdown of ECSOD in mouse fibrotic lungs impairs fibrosis resolution. Mechanistically, we demonstrate that transforming growth factor (TGF)-β1 downregulates endogenous ECSOD expression, leading to the accumulation of extracellular superoxide via Smad-mediated signaling and the activation of additional stores of latent TGF-β1. In addition, depletion of endogenous ECSOD during the fibrotic phase in the bleomycin model induces an apoptosis-resistant phenotype in lung fibroblasts through unrestricted Akt signaling. Taken together, our data strongly support the critical role of extracellular redox state in fibrosis persistence and resolution. Based on these findings, we propose that compartment-specific control over extracellular ROS may be a potential therapeutic strategy for managing fibrotic lung disorders.

Sohlh2 promotes pulmonary fibrosis via repression of p62/Keap1/Nrf2 mediated anti-oxidative signaling pathway

Disturbance in the redox balance of alveolar epithelial cells (AECs) was considered as a causal factor for pulmonary fibrosis. The regulatory mechanisms of redox hemostasis in the development of pulmonary fibrosis remain largely unknown. Using a type II AEC-specific Sohlh2 conditional knock-in (CKI) mouse model, we found that Sohlh2, a basic HLH transcription factor, accelerated age-related pulmonary fibrosis. High-fat diet (HFD) resulted in a tremendous increase in lung inflammation and fibrotic changes in the lung tissues of Sohlh2 CKI mice. Sohlh2 overexpression led to a significant rise of intracellular ROS and apoptosis in the lung, mouse primary AECIIs, and human A549 cells, which was attenuated by ROS inhibitor (NAC). Sohlh2 enhanced oxidative stress via repressing p62/Keap1/Nrf2 mediated anti-oxidative signaling pathway. p62, a direct target of Sohlh2, mediated Sohlh2 effects on ROS generation and apoptosis in A549 cells. Hence, our findings elucidate a pivotal mechanism underlying oxidative stress-induced pulmonary fibrosis, providing a framework for aging-related disorder interventions.

Evaluation of possible attenuative role of chrysoeriol against polyethylene microplastics instigated testicular damage: A biochemical, spermatogenic and histological study

The current study was designed to evaluate the protective role of chrysoeriol against polyethylene microplastics (PE-MP) induced testicular damage. Forty eight male rats were distributed into 4 equal groups: vehicle control, PE-MP administrated, PE-MP + chrysoeriol co-administrated and only chrysoeriol supplemented group. The administration of PE-MP significantly reduced the activities of anti-oxidant enzymes, i.e., glutathione peroxidase, catalase, glutathione reductase and superoxide dismutase, whereas the levels of reactive oxygen species and malondialdehyde were increased. PE-MP exposure increased the levels of inflammatory markers (TNF-α, 1L-1β, NF-κβ, IL-6 & COX-2). Additionally, a considerable increase was observed in dead sperms number, abnormality of sperms (tail, midpiece and head), while a potential decrease was noticed in sperm motility in PE-MP treated rats. The expressions of steroidogenic enzymes were also decreased in PE-MP administrated group. The levels of plasma testosterone, luteinizing & follicle stimulating hormone were decreased in PE-MP treated group. Moreover, Bax and Caspase-3 expressions were increased, whereas Bcl-2 expressions were reduced. Furthermore, histopathological analysis showed that PE-MP exposure considerably damaged the testicular tissues. However, chrysoeriol supplementation potentially decreased all the adverse effects induced by PE-MP. Taken together, our findings indicate that chrysoeriol holds significant potential to avert PE-MP-induced testicular damage due to its androgenic, anti-apoptotic, anti-oxidant and anti-inflammatory nature.

Mitigative potential of rhoifolin against cisplatin prompted testicular toxicity: biochemical, spermatogenic and histological based analysis

Rhoifolin (ROF) is a naturally occurring flavonoid compound with diverse pharmacological and therapeutic benefits. The current investigation was designed to evaluate the curative potential of Rhoifolin (ROF) against Cisplatin (CP) induced testicular damage. Mature male albino rats (n = 48) were randomly distributed into 4 equal groups: control, CP (10 mg/kg), CP + ROF (10 mg/kg + 20 mg/kg) and ROF (20 mg/kg) supplemented group. Following 56 days of the trial, biochemical, inflammatory markers, spermatogenic, steroidogenic, hormonal, apoptotic, anti-apoptotic, and histopathological parameters were evaluated. The exposure to CP markedly (p < 0.05) lowered the activities of anti-oxidant enzymes, glutathione reductase (GSR), catalase (CAT), and glutathione peroxidase (GPx) as well as superoxide dismutase (SOD) in testicular tissues of male albino rats. Besides the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) were considerably augmented in CP exposed rats. The administration of CP also increased the level of inflammatory cytokines i.e. IL-6, TNF-α, 1L-1β and NF-κβ as well as COX-2 activity. Additionally, a notable (p < 0.05) upsurge was observed in dead sperms count, abnormality in the tail, midpiece as well as head of sperms along with a notable decline in sperm motility in CP treated rats. Moreover, the expressions of steroidogenic enzymes were also lowered in CP administered group. The levels of follicle stimulating hormone (FSH) and plasma testosterone as well as luteinizing hormone (LH) were decreased in CP treated group. Moreover, the expression of Bax as well as Caspase-3 (apoptotic markers) were increased. On the other hand, Bcl-2 expression (anti-apoptotic marker) was reduced. Furthermore, the histopathological analysis showed that CP considerably (p < 0.05) damaged the testicular tissues. However, the administration of ROF significantly reduced the damaging effects of CP in testicular tissues. The results of our study suggested that ROF can potentially alleviate CP-induced testicular damages due to its androgenic, anti-oxidant and anti-inflammatory as well as anti-apoptotic nature.

Idiopathic pulmonary fibrosis (IPF): disease pathophysiology, targets, and potential therapeutic interventions

Idiopathic pulmonary fibrosis (IPF) is a progressive, degenerative pulmonary condition. Transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), and tumor necrosis factor-α (TNF-α) are the major modulators of IPF that mediate myofibroblast differentiation and promote fibrotic remodeling of the lung. Cigarette smoke, asbestos fiber, drugs, and radiation are known to favor fibrotic remodeling of the lungs. Oxidative stress in the endoplasmic reticulum (ER) also leads to protein misfolding and promotes ER stress, which is predominant in IPF. This phenomenon further results in excess reactive oxygen species (ROS) aggregation, increasing oxidative stress. During protein folding in the ER, thiol groups on the cysteine residue are oxidized and disulfide bonds are formed, which leads to the production of hydrogen peroxide (H2O2) as a by-product. With the accumulation of misfolded proteins in the ER, multiple signaling cascades are initiated by the cell, collectively termed as the unfolded protein response (UPR). UPR also induces ROS production within the ER and mitochondria and promotes both pro-apoptotic and pro-survival pathways. The prevalence of post-COVID-19 pulmonary fibrosis (PCPF) is 44.9%, along with an alarming increase in "Coronavirus Disease 2019" (COVID-19) comorbidities. Fibrotic airway remodeling and declined lung function are the common endpoints of SARS-CoV-2 infection and IPF. Flavonoids are available in our dietary supplements and exhibit medicinal properties. Apigenin is a flavonoid found in plants, including chamomile, thyme, parsley, garlic, guava, and broccoli, and regulates several cellular functions, such as oxidative stress, ER stress, and fibrotic responses. In this study, we focus on the IPF and COVID-19 pathogenesis and the potential role of Apigenin in addressing disease progression.

Vitamin D alleviates hypothyroidism associated liver dysfunction: Histological and biochemical evidence

There is a complex correlation between thyroid hormones (THs) and liver function. Hypothyroidism as a failure of the thyroid gland to produce adequate thyroid hormones to fulfill the metabolic requirements of the body, may perturb liver structure and function. Emerging evidence suggests the protective effects of vitamin D against liver damage. Herein, this study aimed to investigate the role of vitamin D in hypothyroidism-associated liver injury. Forty male Wistar rats were classified into 4 groups: control, hypothyroid (Hypo) group received 0.05% PTU, Hypo- Vitamin D groups were given 100 and 500 IU/kg vitamin D orally via gavage for 6 weeks. Serum level of liver function including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were measured. Malondialdehyde (MDA) level, superoxide dismutase (SOD) enzyme activity, and total thiol content were measured as oxidative stress indicators in the liver tissue. Furthermore, to estimate liver tissue fibrosis, Masson's trichrome staining was done. Our findings showed that hypothyroidism-induced liver fibrosis was associated with increased levels of ALT, AST and ALP. Though, vitamin D administration could significantly reduce the ALT, AST and ALP in the serum and suppress the accumulation of collagen fibers. Moreover, the activity of SOD and total thiol content was notably reduced, while the MDA content was significantly increased in the PTU- induced hypothyroid rats compared to the control group. Nonetheless, treatment with vitamin D improved mentioned oxidative stress markers in the Hypo-vitamin D groups. In conclusion, vitamin D due to its potential antioxidant and anti-fibrotic properties could be effective in the decrease of hypothyroidism-associated liver injury.

Eriodictyol attenuates Furan induced testicular toxicity in Rats: Role of oxidative stress, steroidogenic enzymes and apoptosis

Furan (C₄H₄O) is a naturally occurring organic compound. It develops as a result of the thermal processing of food and stimulates critical impairments in male reproductive tract. Eriodictyol (Etyol) is a natural dietary flavonoid possessing diverse pharmacological potentials. The recent investigation was proposed to ascertain the ameliorative potential of eriodictyol against furan-instigated reproductive dysfunctions. Male rats (n = 48) were classified into 4 groups: untreated/control, furan (10 mg/kg), furan+ eriodictyol (10 mg/kg + 20 mg/kg) and eriodictyol (20 mg/kg). At the 56th day of the trial, the protective effects of eriodictyol were evaluated by assessing various parameters. Results of the study revealed that eriodictyol attenuated furan-induced testicular toxicity in the biochemical profile by increasing catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) along with glutathione reductase (GSR) activities, whereas reduced the reactive oxygen species (ROS) along with malondialdehyde (MDA) levels. It also restored the normal state of sperm motility, viability, the count of hypo-osmotic tail swelled sperm as well as epididymal sperm number along with reduced sperm anomalies (morphological) tail, mid-piece and head. Furthermore, it elevated the decreased levels of luteinizing hormone (LH), plasma testosterone and follicle-stimulating hormone (FSH) as well steroidogenic enzymes (17β-HSD, StAR protein & 3β-HSD) and testicular anti-apoptotic marker (Bcl-2) expression, whereas, down-regulating apoptotic markers (Bax & Caspase-3) expression. Eriodictyol treatment also effectively mitigated the histopathological damages. The outcomes of the current study provide fundamental insights into the ameliorative potential of eriodictyol against furan-instigated testicular toxicity.

Therapeutic effect of gossypetin against paraquat-induced testicular damage in male rats: a histological and biochemical study

Paraquat (PQ) is an organic compound, which is commonly used as a herbicide in the agriculture sector, and it is also known to stimulate critical damages in the male reproductive system. Gossypetin (GPTN) is one of important members of the flavonoid family, which is an essential compound in flowers and calyx of Hibiscus sabdariffa with potential pharmacological properties. The current investigation was aimed to examine the ameliorative potential of GPTN against PQ-instigated testicular damages. Adult male Sprague-Dawley rats (n = 48) were distributed into four groups: control, PQ (5 mg/kg), PQ + GPTN (5 mg/kg + 30 mg/kg respectively), and GPTN (30 mg/kg). After 56 days of treatment, biochemical, spermatogenic indices, hormonal, steroidogenic, pro-or-anti-apoptotic, and histopathological parameters were estimated. PQ exposure disturbed the biochemical profile by reducing the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GSR), while it increased the concentration of reactive oxygen species (ROS) and malondialdehyde (MDA) level. Furthermore, PQ exposure decreased the sperm motility, viability, number of hypo-osmotic tail swelled spermatozoa, and epididymal sperm count; additionally, it increased sperm morphological (head mid-piece and tail) abnormalities. Moreover, PQ lessened the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and plasma testosterone levels. Besides, PQ-intoxication downregulated the gene expression of steroidogenic enzymes (StAR, 3β-HSD, and 17β-HSD) and anti-apoptotic marker (Bcl-2), whereas upregulated the gene expression of apoptotic markers (Bax and Caspase-3). PQ exposure led to histopathological damages in testicular tissues as well. Nonetheless, GPTN inverted all the illustrated impairments in testes. Taken together, GPTN could potently ameliorate PQ-induced reproductive dysfunctions due to its antioxidant, androgenic, and anti-apoptotic potential.

Repurposing of carvedilol to alleviate lung fibrosis in rats: Repressing of TGF-β1/α-SMA/Smad2/3 and STAT3 gene expressions

Idiopathic pulmonary fibrosis (IPF) is the most widely studied interstitial lung disease. IPF eventually leads to respiratory insufficiency, lung cancer, and death. Carvedilol (CAR) is a third-generation β-adrenergic receptor antagonist with α1-blocking effect. CAR demonstrates antifibrotic activities in various experimental models of organ fibrosis.

AIMS

This work is designed to explore the possible alleviating effects of CAR on bleomycin (BLM)-induced lung fibrosis in rats.

MAIN METHODS

The BLM rat model of lung fibrosis was achieved by intratracheal delivery of a single dose of 5 mg/kg of BLM. Seven days following BLM injection, either prednisolone or CAR was orally administered at doses of 10 mg/kg once daily for 21 days to rats. The actions of CAR were evaluated by lung oxidant/antioxidant parameters, protein concentration and total leucocyte count (TLC) in bronchoalveolar lavage fluid (BALF), fibrosis regulator-related genes along with the coexistent lung histological changes.

KEY FINDINGS

CAR effectively decreased lung malondialdehyde level, increased superoxide dismutase activity, declined both protein concentration and TLC in BALF, downregulated TGF-β1/α-SMA/Smad2/3 and STAT3 gene expressions, and repaired the damaged lung tissues.

SIGNIFICANCE

CAR conferred therapeutic potential against BLM-induced lung fibrosis in rats, at least in part, to its antioxidant, anti-inflammatory, and antifibrotic activities. CAR could be utilized as a prospective therapeutic option in patients with lung fibrosis in clinical practice.

Secretome of hESC-Derived MSC-like Immune and Matrix Regulatory Cells Mitigate Pulmonary Fibrosis through Antioxidant and Anti-Inflammatory Effects

Oxidative stress and inflammation are major drivers in the pathogenesis and progression of pulmonary fibrosis (PF). The mesenchymal stem cell (MSC) secretome has regenerative potential and immunomodulatory functions. Human embryonic stem cell (hESC)-derived MSC-like immune and matrix regulatory cells (IMRCs) are manufacturable with large-scale good manufacturing practice (GMP) preparation. In the present study, the antioxidative and anti-inflammatory properties and the therapeutic effect of the secretome of hESC-MSC-IMRC-derived conditioned culture medium (CM) (hESC-MSC-IMRC-CM) were investigated. Results revealed the capacities of hESC-MSC-IMRC-CM to reduce bleomycin (BLM)-induced reactive oxygen species (ROS), extracellular matrix (ECM) deposition, and epithelial-mesenchymal transition (EMT) in A549 cells. The administration of concentrated hESC-MSC-IMRC-CM significantly alleviated the pathogenesis of PF in lungs of BLM-injured mice, as accessed by pathohistological changes and the expression of ECM and EMT. A mechanistic study further demonstrated that the hESC-MSC-IMRC-CM was able to inhibit BLM-induced ROS and pro-inflammatory cytokines, accompanied by a reduced expression of Nox4, Nrf2, Ho-1, and components of the Tlr4/MyD88 signaling cascade. These results provide a proof of concept for the hESC-MSC-IMRC-derived secretome treatment of PF, in part mediated by their antioxidative and anti-inflammatory effects. This study thus reinforces the development of ready-to-use, cell-free hESC-MSC-IMRC secretome biomedicine for the treatment of PF in clinical settings.

A mitochondrial-targeted near-infrared fluorescent probe for visualizing the fluctuation of hypochlorite acid in idiopathic pulmonary fibrosis mice

Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory disease destroying lungs irreversibly with high mortality rates. There are challenges in diagnosing IPF and treating it at an early stage. Mounting evidence suggests that hypochlorous acid (HClO) can help in diagnosing inflammation and relevant conditions. Pulmonary fibrosis is linked to the mitochondrial oxidative stress where excessive HClO production is a key molecular mechanism. Measuring mitochondrial HClO levels assists in the investigations of how the mitochondrial oxidative stress affects IPF. Herein, NIR-PTZ-HClO was developed and optimized as a probe for detecting fluctuations in HClO concentrations of cells and mice models through near-infrared (NIR) fluorescence. The probe featured large Stokes shift of 150 nm, NIR turn-on signal at 650 nm, high sensitivity (45-fold) and quick HClO detection (2 s). The probe is selective for HClO in the presence of range of other analytes. NIR-PTZ-HClO visualized both endogenous and exogenous HClO in living cells (RAW264.7, H460 and A549). The probe monitored HClO in mice models with IPF and moreover the HClO profile could be tracked during the IPF process. The probe also detected precipitous decrease in HClO levels in IPF mice treated with OFEV. NIR-PTZ-HClO probe has thus the potential for earlier diagnosis of lung fibrosis, thereby improving the treatment efficacy.

Effect of Capparis spinosa Fruit Hydroalcoholic Extract on Paraquat-Induced Pulmonary Fibrosis in the Rat

Pulmonary fibrosis (PF) is a lethal inflammatory disease and there has been no effective medication for this progressive disease up to now. Paraquat is commonly used in agricultural settings to control weed growth and is one of the important risk factors for PF. Additionally, emerging evidence has demonstrated Capparis spinosa (C. spinose) fruit extract has anti-fibrotic, anti-inflammatory, and antioxidant properties. We aimed to evaluate whether C. spinose fruit hydroalcoholic extract has a positive effect against Paraquat-induced PF in rats. 30 male Wistar rats were randomly divided into 5 groups, which included: a control group, a Paraquat control group, a C. spinose group with a dose of 20 mg/kg, a C. spinose group with a dose of 30 mg/kg, a C. spinose group with a dose of 50 mg/kg. After 21 days of the treatment, levels of hydroxyproline and malondialdehyde (MDA) in lung tissue were assessed and lung indices and semi-quantitative histopathological changes were determined. The results showed that treatment with C. spinose, led to increased weight gain, whereas reduced lung weight. C. spinose demonstrated a decreasing effect on levels of MDA, and hydroxyproline in lung tissue. Moreover, histopathological data and the number of lung indices indicated the preventive role of C. spinose Paraquat-induced PF in rats.

Long-term exposure to PM2.5 aggravates pulmonary fibrosis and acute lung injury by disrupting Nrf2-mediated antioxidant function

Epidemiological studies have indicated that exposure to ambient air-borne fine particulate matter (PM2.5) is associated with many cardiopulmonary diseases; however, the underlying pathological mechanisms of PM2.5-induced lung injury remain unknown. In this study, we aimed to assess the impact of acute or prolonged exposure to water-insoluble fractions of PM2.5 (PM2.5 particulate) on lung injury and its molecular mechanisms. Balb/c mice were randomly exposed to PM2.5 once (acute exposure) or once every three days for a total of 6 times (prolonged exposure). Lung, BALF and blood samples were collected, and pulmonary pathophysiological alterations were analyzed. Nrf2 knockout mice were adapted to assess the involvement of Nrf2 in lung injury, and transcriptomic analysis was performed to delineate the mechanisms. Through transcriptomic analysis and validation of Nrf2 knockout mice, we found that acute exposure to PM2.5 insoluble particulates induced neutrophil infiltration-mediated airway inflammation, whereas prolonged exposure to PM2.5 insoluble particulate triggered lung fibrosis by decreasing the transcriptional activity of Nrf2, which resulted in the downregulated expression of antioxidant-related genes. In response to secondary LPS exposure, prolonged PM2.5 exposure induced more severe lung injury, indicating that prolonged PM2.5 exposure induced Nrf2 inhibition weakened its antioxidative defense capacity against oxidative stress injury, leading to the formation of pulmonary fibrosis and increasing its susceptibility to secondary bacterial infection.

Effects of Different Concentrations of Oil Mist Particulate Matter on Pulmonary Fibrosis In Vivo and In Vitro

Oil-mist particulate matter (OMPM) refers to oily particles with a small aerodynamic equivalent diameter in ambient air. Since the pathogenesis of pulmonary fibrosis (PF) has not been fully elucidated, this study aims to explore the potential molecular mechanisms of the adverse effects of exposure to OMPM at different concentrations in vivo and in vitro on PF. In this study, rats and cell lines were treated with different concentrations of OMPM in vivo and in vitro. Sirius Red staining analysis shows that OMPM exposure could cause pulmonary lesions and fibrosis symptoms. The expression of TGF-β1, α-SMA, and collagen I was increased in the lung tissue of rats. The activities of MMP2 and TIMP1 were unbalanced, and increased N-Cadherin and decreased E-Cadherin upon OMPM exposure in a dose-dependent manner. In addition, OMPM exposure could activate the TGF-β1/Smad3 and TGF-β1/MAPK p38 signaling pathways, and the differentiation of human lung fibroblast HFL-1 cells. Therefore, OMPM exposure could induce PF by targeting the lung epithelium and fibroblasts, and activating the TGF-β1/Smad3 and TGF-β1/MAPK p38 signaling pathways.

Molecular Regulation of Heme Oxygenase-1 Expression by E2F Transcription Factor 2 in Lung Fibroblast Cells: Relevance to Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic lung disease. Heme oxygenase-1 (HMOX1/HO-1) is an enzyme that catalyzes the degradation of heme. The role of HO-1 in the pathogenesis of IPF has been studied; however, the molecular regulation of HO-1 and its role in IPF are still unclear. In this study, we found that HO-1 protein levels significantly increased in lung myofibroblasts in IPF patients and in lungs in a murine model of bleomycin-induced lung fibrosis. In addition, we observed that administration of a E2F transcription factor inhibitor elevated HO-1 mRNA and protein levels in lung fibroblasts. Downregulation of E2F2 by siRNA transfection increased HO-1 mRNA and protein levels, while overexpression of E2F2 reduced HO-1 levels. However, overexpression of E2F2 did not alter hemin-induced HO-1 protein levels. Furthermore, modulation of HO-1 levels regulated TGF-β1-induced myofibroblast differentiation without altering the phosphorylation of Smad2/3 in lung fibroblast cells. Moreover, the phosphorylation of protein kinase B (Akt) was significantly upregulated in HO-1-depleted lung fibroblast cells. In summary, this study demonstrated that E2F2 regulates the baseline expression of HO-1, but has no effect on modulating HO-1 expression by hemin. Finally, elevated HO-1 expression contributes to the TGF-β1-induced lung myofibroblast differentiation through the activation of the serine/threonine kinase AKT pathway. Overall, our findings suggest that targeting E2F2/HO-1 might be a new therapeutic strategy to treat fibrotic diseases such as IPF.

Thromboxane-Prostanoid Receptor Signaling Drives Persistent Fibroblast Activation in Pulmonary Fibrosis

Rationale: Although persistent fibroblast activation is a hallmark of idiopathic pulmonary fibrosis (IPF), mechanisms regulating persistent fibroblast activation in the lungs have not been fully elucidated. Objectives: On the basis of our observation that lung fibroblasts express TBXA2R (thromboxane-prostanoid receptor) during fibrosis, we investigated the role of TBXA2R signaling in fibrotic remodeling. Methods: We identified TBXA2R expression in lungs of patients with IPF and mice and studied primary mouse and human lung fibroblasts to determine the impact of TBXA2R signaling on fibroblast activation. We used TBXA2R-deficient mice and small-molecule inhibitors to investigate TBXA2R signaling in preclinical lung fibrosis models. Measurements and Main Results: TBXA2R expression was upregulated in fibroblasts in the lungs of patients with IPF and in mouse lungs during experimental lung fibrosis. Genetic deletion of TBXA2R, but not inhibition of thromboxane synthase, protected mice from bleomycin-induced lung fibrosis, thereby suggesting that an alternative ligand activates profibrotic TBXA2R signaling. In contrast to thromboxane, F2-isoprostanes, which are nonenzymatic products of arachidonic acid induced by reactive oxygen species, were persistently elevated during fibrosis. F2-isoprostanes induced TBXA2R signaling in fibroblasts and mediated a myofibroblast activation profile due, at least in part, to potentiation of TGF-β (transforming growth factor-β) signaling. In vivo treatment with the TBXA2R antagonist ifetroban reduced profibrotic signaling in the lungs, protected mice from lung fibrosis in three preclinical models (bleomycin, Hermansky-Pudlak mice, and radiation-induced fibrosis), and markedly enhanced fibrotic resolution after bleomycin treatment. Conclusions: TBXA2R links oxidative stress to fibroblast activation during lung fibrosis. TBXA2R antagonists could have utility in treating pulmonary fibrosis.

Contribution of Adiponectin/Carnitine Palmityl Transferase 1A-Mediated Fatty Acid Metabolism during the Development of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that leads rapidly to death. The present study is aimed at discovering the in-depth pathogenesis of IPF, exploring the role of adiponectin/carnitine palmityl transferase 1A- (APN/CPT1A-) mediated fatty acid metabolism during the development of IPF, and excavating its potential mechanism. Here, THP-1 cells were differentiated into M0 macrophages, followed by polarization to M1 macrophages upon hypoxia. Subsequently, lung fibroblast HFL-1 cells were stimulated by M1 macrophages to simulate hypoxia-related IPF condition in vitro. It was discovered that the stimulation of M1 macrophages promoted fibroblast proliferation and fibrosis formation in vitro, accompanied with a disorder of the APN/CPT1A pathway, an overproduction of lipid peroxides, and a low level of autophagy in HFL-1 cells. Thereafter, APN treatment or CPT1A overexpression greatly suppressed above lipid peroxide accumulation, fibroblast proliferation, and fibrosis but activated autophagy in vitro. Furthermore, an in vivo IPF rat model was established by injection of bleomycin (BLM). Consistently, CPT1A overexpression exerted a protective role against pulmonary fibrosis in vivo; however, the antifibrosis property of CPT1A was partly abolished by 3-methyladenine (an autophagy inhibitor). In summary, APN/CPT1A-mediated fatty acid metabolism exerted its protective role in IPF partly through activating autophagy, shedding a new prospective for the treatment of IPF.

Fibropreventive and Antifibrotic Effects of Uncaria gambir on Rats with Pulmonary Fibrosis

Pulmonary fibrosis causes scar tissue formation that disrupts the functioning of the lungs. Uncaria gambir (Hunter) Roxb (hereafter gambir)—a plant native to West Sumatra in Indonesia—contains flavonoid (+)-catechin, which has strong antioxidant activity and can be used to combat pulmonary fibrosis. This random in vivo experimental study analyzed the antifibrotic effect of gambir on the lungs of rats with bleomycin-induced fibrosis. The subjects were 10 groups of 10-week-old male rats weighing around 200–250 g. All groups were terminated at the end of the seventh week or on day 50. The lungs were cleaned, and tissues were taken to analyze inflammatory cell counts and TGF-β1 levels using bronchoalveolar lavage (BAL) with ELISA; type I collagen and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels using immunohistochemistry (IHC); and activation of NF-κB using ELISA and Western blot assays. The most severe histopathological characteristic based on the modified Ashcroft score was in the bleomycin group (BG), whereas the mildest was in the 262 mg/kg of the bodyweight antifibrotic gambir-dosed group (AF G262). The results showed a significant difference in the BAL inflammatory cell count (p=0.017; p < 0.05). AF G262 differed most from the other antifibrotic groups in terms of the number of inflammatory cells (0.63), TGF-β1 levels (3.80), and NF-κB levels (0.48), followed by the 131 mg/kg of the bodyweight antifibrotic gambir-dosed group (AF G131), which also differed most from other antifibrotic groups in terms of NF-κB (0.48), TIMP-1 (11.74), and collagen I (14.50) levels. Western blot analysis showed that the fibropreventive and antifibrotic groups had a specific band size of p65, whereas no specific band binding existed in the control group. This study concluded that the administration of AF G262 could improve fibrosis by lysing the extracellular matrix (ECM) in rat lungs.

Nonspecific Interstitial Pneumonitis in a Child Associated With Hashimoto Thyroiditis

Interstitial lung disease (ILD) is a rare disease defined as a specific type of chronic fibrosing interstitial pneumonitis whose effects are limited to the lung. Nonspecific interstitial pneumonia (NSIP) was defined as a histopathological form that can be seen in the presence of large different clinical and radiological features.

The exact role of thyroid hormone in the pathogenetic mechanism of idiopathic interstitial pneumonitis (IIP) is unclear. But there is a suggestion that the thyroid hormone plays a role in pulmonary inflammation and fibrosis. In this case report, we described the presentation of NSIP which was associated with Hashimoto thyroiditis.

Pulmonary Protein Oxidation and Oxidative Stress Modulation by Lemna minor L. in Progressive Bleomycin-Induced Idiopathic Pulmonary Fibrosis

Bleomycin (BLM) administration is associated with multifunctional proteins inflammations and induction of idiopathic pulmonary fibrosis (IPF). Lemna minor L. extract, a free-floating monocot macrophyte possesses antioxidant and anti-inflammatory potential. The aim of the study was to examine the protective effect of L. minor extract on lung protein oxidation and oxidative stress modulation by BLM-induced pulmonary fibrosis in Balb/c mice. For this purpose, the protein carbonyl content, advanced glycation end product, nitroxide protein oxidation (5-MSL), and lipid peroxidation (as MDA and ROS), in lung cells were examined. The histological examinations, collagen deposition, and quantitative measurements of IL-1β, IL-6, and TNF in lung tissues and blood were investigated. Intraperitoneal, BLM administration (0.069 U/mL; 0.29 U/kg b.w.) for 33 days, caused IPF induction in Balb/c mice. Pulmonary combining therapy was administered with L. minor at dose 120 mg/mL (0.187 mg/kg b.w.). L. minor histologically ameliorated BLM induced IPF in lung tissues. L. minor significantly modulated (p < 0.05) BLM-alterations induced in lung hydroxyproline, carbonylated proteins, 5-MSL-protein oxidation. Oxidative stress decreased levels in antioxidant enzymatic and non-enzymatic systems in the lung were significantly regulated (p < 0.05) by L. minor. L. minor decreased the IL-1β, IL-6, and TNF-α expression in lung tissues and plasma. The L. minor improves the preventive effect/defense response in specific pulmonary protein oxidation, lipid peroxidation, ROS identifications, and cytokine modulation by BLM-induced chronic inflammations, and could be a good antioxidant, anti-inflammatory, and anti-fibrotic alternative or IPF prevention involved in their pathogenesis.

Pachypodol attenuates Perfluorooctane sulphonate-induced testicular damage by reducing oxidative stress

Perfluorooctane sulfonate (PFOS) is an endocrine disruptor chemical (EDC) with potentially adverse effects on the male reproductive system. Pachypodol (5,4'-dihydroxy-3,7,3'-trimethoxyflavone) is a promising flavonoid isolated from Pogostemon cablin (Blanco) Benth that shows a broad range of pharmacological properties. However, the potential curative effects of pachypodol on testicular toxicity are not available until now. Therefore, this research was proposed to examine the efficiency of pachypodol against PFOS-induced testicular toxicity in adult male rats. The experiments were conducted on Sprague-Dawley rats (n = 48), which were equally distributed into four groups: control, PFOS (20 mg/kg), PFOS + Pachypodol (20 mg/kg + 10 mg/kg respectively), and Pachypodol (10 mg/kg). After 56 days of treatment, testes were excised by slaughtering rats, weighed, and stored till further analysis. The estimated parameters include biochemical markers, spermatogenic indices, hormonal and histopathological profiles. PFOS exposure disturbed the biochemical profile by altering the antioxidant/oxidant balance. For instance, it decreased the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GSR) while increasing the concentration of reactive oxygen species (ROS) and level of thiobarbituric acid reactive substances (TBARS). PFOS intoxication also led to a notable decline in viability, motility, epididymal sperm count, and the number of HOS coiled-tail sperms, whereas the higher level of abnormality in the head, mid-piece, and tail of sperms were observed. Besides, it lowered luteinizing hormone (LH), follicle-stimulating hormone (FSH), and plasma testosterone. In addition, PFOS exposure led to histopathological damages in testicles. However, pachypodol treatment potently alleviated all the illustrated impairments in testes. Conclusively, our results demonstrate the promising free-radical scavenging activity of pachypodol, a novel phytochemical, against the PFOS-instigated testicular dysfunctions.

Pathogenic Mechanisms Underlying Idiopathic Pulmonary Fibrosis

The pathogenesis of idiopathic pulmonary fibrosis (IPF) involves a complex interplay of cell types and signaling pathways. Recurrent alveolar epithelial cell (AEC) injury may occur in the context of predisposing factors (e.g., genetic, environmental, epigenetic, immunologic, and gerontologic), leading to metabolic dysfunction, senescence, aberrant epithelial cell activation, and dysregulated epithelial repair. The dysregulated epithelial cell interacts with mesenchymal, immune, and endothelial cells via multiple signaling mechanisms to trigger fibroblast and myofibroblast activation. Recent single-cell RNA sequencing studies of IPF lungs support the epithelial injury model. These studies have uncovered a novel type of AEC with characteristics of an aberrant basal cell, which may disrupt normal epithelial repair and propagate a profibrotic phenotype. Here, we review the pathogenesis of IPF in the context of novel bioinformatics tools as strategies to discover pathways of disease, cell-specific mechanisms, and cell-cell interactions that propagate the profibrotic niche.

The nitroxide/antioxidant 3-carbamoyl proxyl attenuates disease severity in murine models of severe asthma

Asthma is characterized by airway inflammation, hyper-responsiveness, symptoms of dyspnea, wheezing and coughing. In most patients, asthma is well controlled using inhaled corticosteroids and bronchodilators. A minority of patients with asthma develop severe disease, which is frequently only partially responsive or even resistant to treatment with corticosteroids. Severe refractory asthma is associated with structural changes in the airways, termed "airway remodeling", and/or with neutrophilic rather than eosinophilic airway inflammation. While oxidative stress plays an important role in the pathophysiology of asthma, cyclic nitroxide stable radicals, which are unique and efficient catalytic antioxidants, effectively protect against oxidative injury. We have demonstrated that the nitroxide 3-carbamoyl proxyl (3-CP) attenuates airway inflammation and hyperresponsiveness in allergic asthma as well as bleomycin-induced fibrosis both using murine models, most probably through modulation of oxidative stress. The present study evaluates the effect of 3-CP on airway inflammation and remodeling using two murine models of severe asthma where mice are sensitized and challenged either by ovalbumin (OVA) or by house dust mite (HDM). 3-CP was orally administered during the entire period of the experiment or during the challenge period alone where its effect was compared to that of dexamethasone. The induced increase by OVA and by HDM of BALf cell counts, airway hyperresponsiveness, fibrosis, transforming growth factor-beta (TGF-β) levels in BALf and protein nitration levels of the lung tissue was significantly reduced by 3-CP. The effect of 3-CP, using two different murine models of severe asthma, is associated at least partially with attenuation of oxidative stress and with TGF-β expression in the lungs. The results of this study suggest a potential use of 3-CP as a novel therapeutic agent in different forms of severe asthma.

Mendelian randomisation highlights hypothyroidism as a causal determinant of idiopathic pulmonary fibrosis

Background

Although the association between hypothyroidism and idiopathic pulmonary fibrosis (IPF) is found in observational studies, it remains uncertain whether hypothyroidism causally influences IPF.

Methods

Two-sample Mendelian randomisation (MR) was conducted with hypothyroidism genome-wide association study (GWAS) data in the UK Biobank from 289,307 individuals (18,740 cases and 270,567 controls) and the largest GWAS summary statistics of IPF from 11,259 individuals (2,668 cases and 8,591 controls). Findings were verified using an independent validation dataset, as well as through different MR methods with different model assumptions. A multivariable MR based on Bayesian model averaging was further performed to evaluate whether hypothyroidism, even given several other comorbidities of IPF, remained to be the true causal one of IPF.

Findings

A positive causal effect of hypothyroidism on IPF was revealed (MR inverse-variance weighted [MR-IVW], odds ratio [OR]=1.125, 95% confidence interval [CI] 1.028-1.231; P=0.011), which was further verified in an independent validation set (MR-IVW, OR=1.229, 95% CI 1.054-1.432; P=0.008). The results were consistent from a variety of MR methods. Bidirectional analyses also indicated no reverse causation. Multivariable MR analysis showed hypothyroidism had the strongest marginal evidence (marginal inclusion probability=0.397, false discovery rate=0.025) compared with other comorbidities of IPF.

Interpretation

Our results illustrate the significant causal effect of hypothyroidism on IPF, which holds even given several other comorbidities of IPF. These findings may have an important insight into pathogenesis and possible future therapies of IPF.

Funding

National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province and the Young Scholars Program of Shandong University.

The Role of Interaction between Mitochondria and the Extracellular Matrix in the Development of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a condition which affects mainly older adults, that suggests mitochondrial dysfunction and oxidative stress, which follow cells senescence, and might contribute to the disease onset. We have assumed pathogenesis associated with crosstalk between the extracellular matrix (ECM) and mitochondria, mainly based on mitochondrial equilibrium impairment consisting of (1) tyrosine kinases and serine-threonine kinase (TKs and ST-Ks) activation via cytokines, (2) mitochondrial electron transport chain dysfunction and in consequence electrons leak with lower ATP synthesis, (3) the activation of latent TGF-β via αVβ6 integrin, (4) tensions transduction via α2β1 integrin, (5) inefficient mitophagy, and (6) stress inhibited biogenesis. Mitochondria dysfunction influences ECM composition and vice versa. Damaged mitochondria release mitochondrial reactive oxygen species (mtROS) and the mitochondrial DNA (mtDNA) to the microenvironment. Therefore, airway epithelial cells (AECs) undergo transition and secrete cytokines. Described factors initiate an inflammatory process with immunological enhancement. In consequence, local fibroblasts exposed to harmful conditions transform into myofibroblasts, produce ECM, and induce progression of fibrosis. In our review, we summarize numerous aspects of mitochondrial pathobiology, which seem to be involved in the pathogenesis of lung fibrosis. In addition, an increasing body of evidence suggests considering crosstalk between the ECM and mitochondria in this context. Moreover, mitochondria and ECM seem to be important players in the antifibrotic treatment of IPF.

The Role of Oxidative Stress in Sarcoidosis

Sarcoidosis is a rare, systemic inflammatory disease whose diagnosis and management can pose a challenge for clinicians and specialists. Scientific knowledge on the molecular pathways that drive its development is still lacking, with no standardized therapies available and insufficient strategies to predict patient outcome. In recent years, oxidative stress has been highlighted as an important factor in the pathogenesis of sarcoidosis, involving several enzymes and molecules in the mechanism of the disease. This review presents current data on the role of oxidative stress in sarcoidosis and its interaction with inflammation, as well as the application of antioxidative therapy in the disease.

Role of Nrf2 in Disease: Novel Molecular Mechanisms and Therapeutic Approaches - Pulmonary Disease/Asthma

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a major transcription factor involved in redox homeostasis and in the response induced by oxidative injury. Nrf2 is present in an inactive state in the cytoplasm of cells. Its activation by internal or external stimuli, such as infections or pollution, leads to the transcription of more than 500 elements through its binding to the antioxidant response element. The lungs are particularly susceptible to factors that generate oxidative stress such as infections, allergens and hyperoxia. Nrf2 has a crucial protective role against these ROS. Oxidative stress and subsequent activation of Nrf2 have been demonstrated in many human respiratory diseases affecting the airways, including asthma and chronic obstructive pulmonary disease (COPD), or the pulmonary parenchyma such as acute respiratory distress syndrome (ARDS) and pulmonary fibrosis. Several compounds, both naturally occurring and synthetic, have been identified as Nrf2 inducers and enhance the activation of Nrf2 and expression of Nrf2-dependent genes. These inducers have proven particularly effective at reducing the severity of the oxidative stress-driven lung injury in various animal models. In humans, these compounds offer promise as potential therapeutic strategies for the management of respiratory pathologies associated with oxidative stress but there is thus far little evidence of efficacy through human trials. The purpose of this review is to summarize the involvement of Nrf2 and its inducers in ARDS, COPD, asthma and lung fibrosis in both human and in experimental models.

Renin angiotensin aldosterone system in pulmonary fibrosis: Pathogenesis to therapeutic possibilities

Pulmonary fibrosis is a devastating lung disease with multifactorial etiology characterized by alveolar injury, fibroblast proliferation and excessive deposition of extracellular matrix proteins, which progressively results in respiratory failure and death. Accumulating evidence from experimental and clinical studies supports a central role of the renin angiotensin aldosterone system (RAAS) in the pathogenesis and progression of idiopathic pulmonary fibrosis. Angiotensin II (Ang II), a key vasoactive peptide of the RAAS mediates pro-inflammatory and pro-fibrotic effects on the lungs, adversely affecting organ function. Recent years have witnessed seminal discoveries in the field of RAAS. Identification of new enzymes, peptides and receptors has led to the development of several novel concepts. Of particular interest is the establishment of a protective axis of the RAAS comprising of Angiotensin converting enzyme 2 (ACE2), Angiotensin-(1-7) [Ang-(1-7)], and the Mas receptor (the ACE2/Ang-(1-7)/Mas axis), and the discovery of a functional role for the Angiotensin type 2 (AT₂) receptor. Herein, we will review our current understanding of the role of RAAS in lung fibrogenesis, provide evidence on the anti-fibrotic actions of the newly recognized RAAS components (the ACE2/Ang-(1-7)/Mas axis and AT₂ receptor), discuss potential strategies and translational efforts to convert this new knowledge into effective therapeutics for PF.

Involvement of 4-hydroxy-2-nonenal in the pathogenesis of pulmonary fibrosis

Pulmonary fibrosis is a chronic progressive disease with high incidence, prevalence, and mortality rates worldwide. It is characterized by excessive accumulation of extracellular matrix in the lung parenchyma. The cellular and molecular mechanisms involved in its pathogenesis are complex, and some are still unknown. Several studies indicate that oxidative stress, characterized by overproduction of 4-hydroxy-2-nonenal (4-HNE), is an important player in pulmonary fibrosis. 4-HNE is a highly reactive compound derived from polyunsaturated fatty acids that can react with proteins, phospholipids, and nucleic acids. Thus, many of the altered cellular mechanisms that contribute to this disease can be explained by the participation of 4-HNE. Here, we summarize the current knowledge on the molecular states and signal transduction pathways that contribute to the pathogenesis of pulmonary fibrosis. Furthermore, we describe the participation of 4-HNE in various mechanisms involved in pulmonary fibrosis development, with a focus on the cell populations involved in the initiation, development, and maintenance of the fibrotic process, mainly alveolar cells, endothelial cells, macrophages, and inflammatory cells. Due to its characteristic activity as a second messenger, 4-HNE, in addition to being a consequence of oxidative stress, can support maintenance of the inflammatory and fibrotic process by spreading the effects of reactive oxygen species (ROS). Thus, regulation of 4-HNE levels could be a viable strategy to reduce its effects on the mechanisms involved in pulmonary fibrosis development.

3-Carbamoyl-proxyl nitroxide radicals attenuate bleomycin-induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with a poor prognosis and limited treatment options. Oxidative and nitrosative stress is implicated as one of the main pathogenic pathways in IPF. The rationale for the use of antioxidants to treat lung fibrosis is appealing, however to date a consistent beneficial effect for such an approach has not been observed. We have recently demonstrated that nitroxides, particularly 3-carbamoyl-proxyl (3-CP), markedly reduce airway inflammation, airway hyper-responsiveness, and protein nitration of the lung tissue in a mouse model of ovalbumin-induced acute asthma, thus prompting its use for the treatment of IPF. The present study investigates the effect of 3-CP on the development of lung fibrosis using the murine intratracheal bleomycin model. 3-CP was administered either intranasally or orally during the entire experiment or starting 7 days after induction of the lung injury. 3-CP was found to be both a preventive and a therapeutic drug reducing the lung fibrosis (histological score), the increase in collagen content, protein nitration, TGF-β levels, the degree of weight loss as well as inhibiting the impairment of lung function. Nitroxides are catalytic antioxidants that preferentially detoxify radicals, and therefore the effect of 3-CP on the severity of the disease supports the involvement of reactive oxygen and nitrogen species in the disease pathology.

Chronic lung inflammation and pulmonary fibrosis after multiple intranasal instillation of PM2 .5 in mice

Fine particulate matter (PM_2.5 ) is an important component of air pollution and can induce lung inflammation and oxidative stress. We hypothesized that PM_2.5 could play a role in the induction of pulmonary fibrosis. We examined whether multiple intranasal instillation of PM_2.5 can induce pulmonary fibrosis in the mouse, and also investigated the underlying pro-fibrotic signaling pathways. C57/BL6 mice were intranasally instilled with 50 μl of PM_2.5 suspension (7.8 μg/g body weight) or PBS three times a week over 3 weeks, 6 weeks or 9 weeks. To observe the recovery of pulmonary fibrosis after the termination of PM_2.5 exposure, 9 week-PM_2.5 instilled mice were also studied at 3 weeks after termination of instillation. There were significant decreases in total lung capacity (TLC) and compliance (Cchord) in the 9-week PM_2.5 -instilled mice, while there were increased histological fibrosis scores with enhanced type I collagen and hydroxyproline deposition, increased mitochondrial ROS levels and NOX activity, decreased total SOD and GSH levels, accompanied by decreased mitochondrial number and aberrant mitochondrial morphology (swelling, vacuolization, cristal disruption, reduced matrix density) in PM_2.5 -instilled mice. Multiple PM_2.5 instillation resulted in increased expression of TGFβ1, increases of N-Cadherin and Vimentin and a decrease of E-Cadherin. It also led to decreases in OPA1 and MFN2, and increases in Parkin, SQSTM1/p62, the ratio of light china (LC) 3B II to LC3B I, PI3k/Akt phosphorylation, and NLRP3 expression. Intranasal instillation of PM_2.5 for 9 weeks induced lung inflammation and pulmonary fibrosis, which was linked with aberrant epithelial-mesenchymal transition, oxidative stress, mitochondrial damage and mitophagy, as well as activation of TGFβ1-PI3K/Akt, TGFβ1- NOX and TGFβ1-NLRP3 pathways.

Circulating Malondialdehyde Concentrations in Obstructive Sleep Apnea (OSA): A Systematic Review and Meta-Analysis with Meta-Regression

Oxidative stress induced by nocturnal intermittent hypoxia plays a significant pathophysiological role in obstructive sleep apnea (OSA). Malondialdehyde (MDA), one of the most commonly investigated markers of lipid peroxidation, might assist with the monitoring of oxidative balance in OSA. We conducted a systematic review and meta-analysis to evaluate the differences in circulating MDA concentrations between patients with OSA and non-OSA controls. A systematic search was conducted in the electronic databases Pubmed, Web of Science, Scopus and Google Scholar from inception to December 2020 by using the following terms: “malondialdehyde” or “MDA”; and “Obstructive Sleep Apnea Syndrome”, “OSAS” or “OSA”. We identified 26 studies in 1223 OSA patients and 716 controls. The pooled MDA concentrations were significantly higher in patients with OSA (standardized mean difference (SMD) 1.43 μmol/L, 95% confidence interval (CI) 1.03 to 1.83 μmol/L, p < 0.001). There was extreme heterogeneity between the studies (I² = 92.3%, p < 0.001). In meta-regression analysis, the SMD was significantly associated with age, the assay type used and publication year. In our meta-analysis, MDA concentrations were significantly higher in OSA patients than in controls. This finding suggests that MDA, which is a marker of lipid peroxidation, is involved in the pathogenesis of OSA and provides insights for future studies investigating its potential clinical use.

Inhibiting HDAC3 (Histone Deacetylase 3) Aberration and the Resultant Nrf2 (Nuclear Factor Erythroid-Derived 2-Related Factor-2) Repression Mitigates Pulmonary Fibrosis

[Figure: see text].

Idiopathic pulmonary fibrosis and systemic sclerosis: pathogenic mechanisms and therapeutic interventions

Fibrotic diseases take a very heavy toll in terms of morbidity and mortality equal to or even greater than that caused by metastatic cancer. In this review, we examine the pathogenesis of fibrotic diseases, mainly addressing triggers for induction, processes that lead to progression, therapies and therapeutic trials. For the most part, we have focused on two fibrotic diseases with lung involvement, idiopathic pulmonary fibrosis, in which the contribution of inflammatory mechanisms may be secondary to non-immune triggers, and systemic sclerosis in which the contribution of adaptive immunity may be predominant.

Protective Effects of Extracellular Matrix-Derived Hydrogels in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease with significant gas exchange impairment owing to exaggerated extracellular matrix (ECM) deposition and myofibroblast activation. IPF has no cure, and although nintedanib and pirfenidone are two approved medications for symptom management, the total treatment cost is exuberant and prohibitive to a global uninsured patient population. New therapeutic alternatives with moderate costs are needed to treat IPF. ECM hydrogels derived from decellularized lungs are cost-effective therapeutic candidates to treat pulmonary fibrosis because of their reported antioxidant properties. Oxidative stress contributes to IPF pathophysiology by damaging macromolecules, interfering with tissue remodeling, and contributing to myofibroblast activation. Thus, preventing oxidative stress has beneficial outcomes in IPF. For this purpose, this review describes ECM hydrogel's properties to regulate oxidative stress and tissue remodeling in IPF.

Repurposing Anticancer Drugs for the Treatment of Idiopathic Pulmonary Fibrosis and Antifibrotic Drugs for the Treatment of Cancer: State of the Art

Idiopathic pulmonary fibrosis (IPF) is an aggressive pulmonary disease which shares several molecular, pathophysiological and clinical aspects with lung cancer, including high mortality rates. The antifibrotic drugs Nintedanib and Pirfenidone have recently been introduced in clinical practice for the treatment of IPF. Nintedanib is also used for the treatment of several malignancies, including non-small cell lung cancer (NSCLC) in combination with Docetaxel, while Pirfenidone showed some anti-neoplastic effects in preclinical studies. On the other hand, novel targeted agents and immunotherapies have been introduced in the last decade for the treatment of NSCLC, and some of them showed anti-fibrotic properties in recent studies. These evidences, based on the common pathophysiological backgrounds of IPF and lung cancer, make possible the mutual or combined use of anti-fibrotic and anti-neoplastic drugs to treat these highly lethal diseases. The aim of the present review is to depict the current scientific landscape regarding the repurposing of anti-neoplastic drugs in IPF and anti-fibrotic drugs in lung cancer, and to identify future research perspectives on the topic.

Tauroursodeoxycholic acid alleviates pulmonary endoplasmic reticulum stress and epithelial-mesenchymal transition in bleomycin-induced lung fibrosis

Background

Several studies demonstrate that endoplasmic reticulum (ER) stress-mediated epithelial-mesenchymal transition (EMT) is involved in the process of bleomycin (BLM)-induced pulmonary fibrosis. Tauroursodeoxycholic acid (TUDCA), a bile acid with chaperone properties, is an inhibitor of ER stress. This study aimed to investigate the preventive effects of TUDCA on BLM-induced EMT and lung fibrosis.

Methods

The model of lung fibrosis was established by intratracheal injection with a single dose of BLM (3.0 mg/kg). In TUDCA + BLM group, mice were intraperitoneally injected with TUDCA (250 mg/kg) daily.

Results

BLM-induced alveolar septal destruction and inflammatory cell infiltration were alleviated by TUDCA. BLM-induced interstitial collagen deposition, as determined by Sirius Red staining, was attenuated by TUDCA. BLM-induced elevation of pulmonary α-smooth muscle actin (α-SMA) and reduction of pulmonary E-cadherin were attenuated by TUDCA. BLM-induced pulmonary Smad2/3 phosphorylation was suppressed by TUDCA. BLM-induced elevation of Ki67 and PCNA was inhibited by TUDCA in mice lungs. In addition, BLM-induced elevation of HO-1 (heme oxygenase-1) and 3-NT (3-nitrotyrosine) was alleviated by TUDCA. Finally, BLM-induced upregulation of pulmonary GRP78 and CHOP was attenuated by TUDCA.

Conclusions

These results provide evidence that TUDCA pretreatment inhibits Smad2/3-medited EMT and subsequent lung fibrosis partially through suppressing BLM-induced ER stress and oxidative stress.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01514-6.