Intestinal host defense outcome is dictated by PGE2 production during efferocytosis of infected cells

Different bacterial cargo in apoptotic cells drive distinct macrophage phenotypes

The removal of dead cells (efferocytosis) contributes to the resolution of the infection and preservation of the tissue. Depending on the environment milieu, macrophages may show inflammatory (M1) or anti-inflammatory (M2) phenotypes. Inflammatory leukocytes are recruited during infection, followed by the accumulation of infected and non-infected apoptotic cells (AC). Efferocytosis of non-infected AC promotes TGF-β, IL-10, and PGE2 production and the polarization of anti-inflammatory macrophages. These M2 macrophages acquire an efficient ability to remove apoptotic cells that are involved in tissue repair and resolution of inflammation. On the other hand, the impact of efferocytosis of infected apoptotic cells on macrophage activation profile remains unknown. Here, we are showing that the efferocytosis of gram-positive Streptococcus pneumoniae-AC (Sp-AC) or gram-negative Klebsiella pneumoniae-AC (Kp-AC) promotes distinct gene expression and cytokine signature in macrophages. Whereas the efferocytosis of Kp-AC triggered a predominant M1 phenotype in vitro and in vivo, the efferocytosis of Sp-AC promoted a mixed M1/M2 activation in vitro and in vivo in a model of allergic asthma. Together, these findings suggest that the nature of the pathogen and antigen load into AC may have different impacts on inducing macrophage polarization.

Non-professional efferocytosis of Salmonella-infected intestinal epithelial cells in the neonatal host

The intestinal epithelium is the first line of defense against enteric pathogens. Removal of infected cells by exfoliation prevents mucosal translocation and systemic infection in the adult host, but is less commonly observed in the neonatal intestine. Instead, here, we describe non-professional efferocytosis of Salmonella-infected enterocytes by neighboring epithelial cells in the neonatal intestine. Intestinal epithelial stem cell organoid cocultures of neonatal and adult cell monolayers with damaged enterocytes replicated this observation, confirmed the age-dependent ability of intestinal epithelial cells for efferocytosis, and identified the involvement of the "eat-me" signals and adaptors phosphatidylserine and C1q as well as the "eat-me" receptors integrin-αv (CD51) and CD36 in cellular uptake. Consistent with this, massive epithelial cell membrane protrusions and CD36 accumulation at the contact site with apoptotic cells were observed in the infected neonatal host in vivo. Efferocytosis of infected small intestinal enterocytes by neighboring epithelial cells may represent a previously unrecognized mechanism of neonatal antimicrobial host defense to maintain barrier integrity.

Koetjapic acid: unveiling its potential as a saviour in the realm of biological and medicinal properties, with a focus on anticancer mechanism of action

Scientists have been compelled to search for alternative treatments due to the increasing prevalence of chemoresistance as well as the agonising and distressing side effects of both chemotherapy and radiation. Plant extracts have been exploited to treat various medical conditions for ages. Considering this fact, the main focus of various recent studies that are being conducted to find new and potent anticancer drugs involves the identification and utilisation of potential therapeutic chemicals present in plant extracts. Koetjapic acid (KJA), which belongs to the family of triterpenes, is primarily isolated from Sandoricum koetjape. Ongoing investigations into its therapeutic applications have revealed its tendency to impede the growth and proliferation of cancer cells. Koetjapic acid activates the intrinsic apoptotic pathway and promotes the death of cancer cells. Moreover, it inhibits angiogenesis and the dissemination of tumour (metastasis) by targeting the VEGF signalling cascade. Therefore, this study aims to elucidate the underlying mechanism of anticancer activity of koetjapic acid, providing significant insight into the compound's potential as an anticancer agent.

Immunohistochemical Characterization of M1, M2, and M4 Macrophages in Leprosy Skin Lesions

Mycobacterium leprae is the etiological agent of leprosy. Macrophages (Mφs) are key players involved in the pathogenesis of leprosy. In this study, immunohistochemical analysis was performed to examine the phenotype of Mφ subpopulations, namely M1, M2, and M4, in the skin lesions of patients diagnosed with leprosy. Based on the database of treatment-naïve patients treated between 2015 and 2019 at the Department of Dermatology of the University of the State of Pará, Belém, routine clinical screening samples were identified. The monolabeling protocol was used for M1 macrophages (iNOS, IL-6, TNF-α) and M2 macrophages (IL-10, IL-13, CD163, Arginase 1, TGF-β, FGFb), and the double-labeling protocol was used for M4 macrophages (IL-6, MMP7, MRP8, TNF-α e CD68). To confirm the M4 macrophage lineage, double labeling of the monoclonal antibodies CD68 and MRP8 was also performed. Our results demonstrated a statistically significant difference for the M1 phenotype among the Virchowian (VV) (4.5 ± 1.3, p < 0.0001), Borderline (1.6 ± 0.4, p < 0.0001), and tuberculoid (TT) (12.5 ± 1.8, p < 0.0001) clinical forms of leprosy. Additionally, the M2 phenotype showed a statistically significant difference among the VV (12.5 ± 2.3, p < 0.0001), Borderline (1.3 ± 0.2, p < 0.0001), and TT (3.2 ± 0.7, p < 0.0001) forms. For the M4 phenotype, a statistically significant difference was observed in the VV (9.8 ± 1.7, p < 0.0001), Borderline (1.2 ± 0.2, p < 0.0001), and TT (2.6 ± 0.7, p < 0.0001) forms. A significant correlation was observed between the VV M1 and M4 (r = 0.8712; p = 0.0000) and between the VV M2 × TT M1 (r = 0.834; p = 0.0002) phenotypes. The M1 Mφs constituted the predominant Mφ subpopulation in the TT and Borderline forms of leprosy, whereas the M2 Mφs showed increased immunoexpression and M4 was the predominant Mφ phenotype in VV leprosy. These results confirm the relationship of the Mφ profile with chronic pathological processes of the inflammatory response in leprosy.

Nonsteroidal anti-inflammatory drugs sensitize epithelial cells to Clostridioides difficile toxin-mediated mitochondrial damage

Clostridioides difficile damages the colonic mucosa through the action of two potent exotoxins. Factors shaping C. difficile pathogenesis are incompletely understood but are likely due to the ecological factors in the gastrointestinal ecosystem, mucosal immune responses, and environmental factors. Little is known about the role of pharmaceutical drugs during C. difficile infection (CDI), but recent studies have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs) worsen CDI. The mechanism underlying this phenomenon remains unclear. Here, we show that NSAIDs exacerbate CDI by disrupting colonic epithelial cells (CECs) and sensitizing cells to C. difficile toxin-mediated damage independent of their canonical role of inhibiting cyclooxygenase (COX) enzymes. Notably, we find that NSAIDs and C. difficile toxins target the mitochondria of CECs and enhance C. difficile toxin-mediated damage. Our results demonstrate that NSAIDs exacerbate CDI by synergizing with C. difficile toxins to damage host cell mitochondria. Together, this work highlights a role for NSAIDs in exacerbating microbial infection in the colon.

Cystathionine gamma-lyase (Cth) induces efferocytosis in macrophages via ERK1/2 to modulate intestinal barrier repair

BACKGROUND

The inflammatory response induced by intestinal ischaemia‒reperfusion injury (I/R) is closely associated with infectious complications and mortality in critically ill patients, and the timely and effective clearance of apoptotic cells is an important part of reducing the inflammatory response. Studies have shown that the efferocytosis by phagocytes plays an important role. Recently, studies using small intestine organoid models showed that macrophage efferocytosis could promote the repair capacity of the intestinal epithelium. However, no studies have reported efferocytosis in the repair of I/R in animal models.

RESULTS

We used an in vivo efferocytosis assay and discovered that macrophage efferocytosis played an indispensable role in repairing and maintaining intestinal barrier function after I/R. In addition, the specific molecular mechanism that induced macrophage efferocytosis was Cth-ERK1/2 dependent. We found that Cth drove macrophage efferocytosis in vivo and in vitro. Overexpression/silencing Cth promoted/inhibited the ERK1/2 pathway, respectively, which in turn affected efferocytosis and mediated intestinal barrier recovery. In addition, we found that the levels of Cth and macrophage efferocytosis were positively correlated with the recovery of intestinal function in clinical patients.

CONCLUSION

Cth can activate the ERK1/2 signalling pathway, induce macrophage efferocytosis, and thus promote intestinal barrier repair. Video Abstract.

Electrolyzed Hydrogen Water Alleviates Abdominal Pain through Suppression of Colonic Tissue Inflammation in a Rat Model of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the digestive tract and is typically accompanied by characteristic symptoms, such as abdominal pain, diarrhea, and bloody stool, severely deteriorating the quality of the patient's life. Electrolyzed hydrogen water (EHW) has been shown to alleviate inflammation in several diseases, such as renal disease and polymyositis/dermatomyositis. To investigate whether and how daily EHW consumption alleviates abdominal pain, the most common symptom of IBD, we examined the antioxidative and anti-inflammatory effects of EHW in an IBD rat model, wherein colonic inflammation was induced by colorectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS). We found that EHW significantly alleviated TNBS-induced abdominal pain and tissue inflammation. Moreover, the production of proinflammatory cytokines in inflamed colon tissue was also decreased significantly. Meanwhile, the overproduction of reactive oxygen species (ROS), which is intricately involved in intestinal inflammation, was significantly suppressed by EHW. Additionally, expression of S100A9, an inflammatory biomarker of IBD, was significantly suppressed by EHW. These results suggest that the EHW prevented the overproduction of ROS due to its powerful free-radical scavenging ability and blocked the crosstalk between oxidative stress and inflammation, thereby suppressing colonic inflammation and alleviating abdominal pain.

Photodynamic Therapy-Induced Cyclooxygenase 2 Expression in Tumor-Draining Lymph Nodes Regulates B-Cell Expression of Interleukin 17 and Neutrophil Infiltration

Photodynamic therapy (PDT) is an effective anticancer modality approved by the U.S. Food and Drug Administration (FDA). Antitumor immunity can be augmented during PDT by inducing sterile inflammation in an acute manner, and this process is characterized by interleukin 17 (IL-17)-mediated neutrophil infiltration to tumor-draining lymph nodes (TDLNs). However, the inflammatory factors that influence IL-17 expression in TDLNs are poorly understood. Prior studies have linked the cyclooxygenase 2 (COX2)-driven prostaglandin E₂ (PGE2) pathway to IL-17 expression. Here, we report that an immune-activating PDT regimen (imPDT) induces COX2/PGE2 expression in TDLNs, whereby IL-17 expression is facilitated without corresponding effects on the expression of RORγt, the transcriptional driver of the canonical IL-17 pathway. Pharmacologic inhibition with NS398, a COX2 inhibitor, was utilized to demonstrate that imPDT-induced COX2 regulates RORγt-independent expression of IL-17 by B cells and neutrophil entry into TDLNs. Depletion of B cells prior to imPDT significantly reduced neutrophil entry into TDLNs following treatment, and diminishes the efficacy of imPDT, which is dependent upon antitumor immunity. These findings are suggestive of a novel role for B cells in the augmentation of antitumor immunity by imPDT.

Mechanisms of efferocytosis in determining inflammation resolution: Therapeutic potential and the association with cardiovascular disease

Efferocytosis is defined as the clearance of apoptotic cells (ACs) in physiological and pathological states and is performed by efferocytes, such as macrophages. Efferocytosis can lead to the resolution of inflammation and restore tissue homoeostasis; however, the mechanisms of efferocytosis in determining inflammation resolution are still not completely understood, and the effects of efferocytosis on other proresolving properties need to be explored and explained. In this review, the process of efferocytosis will be summarized briefly, and then these mechanisms and effects will be thoroughly discussed. In addition, the association between the mechanisms of efferocytosis in determining inflammation resolution and cardiovascular diseases will also be reviewed, as an understanding of this association may provide information on novel treatment targets.

DCs unchained: Whetting dendritic-cell appetite boosts wound healing

Apoptotic-cell uptake (efferocytosis) by dendritic cells (DCs) has been mainly linked to their antigen presentation property. In a recent issue of Nature, Maschalidi et al. identified a break to efferocytosis in DCs, the inhibition of which improves skin debris cleansing after a wound, accelerating healing.

Concentrations of PGE2 and TXB2 in the Eyes of Mice with Disseminated Acanthamoebiasis

Previous studies have shown that Acanthamoeba spp. may invade the eyes by migrating along the optic nerve to the eyes from the brain. This study aimed to confirm the presence of inflammation in the eyes of mice with disseminated acanthamoebiasis by examining prostaglandin E₂ (PGE₂) and thromboxane B₂ (TXB₂) concentrations in the eyes of immunocompetent and immunocompromised mice intranasally inoculated with Acanthamoeba spp. The PGE₂ concentration was statistically significantly lower in the immunocompromised amoebae-infected mice on 8 dpi compared with the noninfected group of animals, and it was higher in the eyes of immunosuppressed amoebae-infected mice on 16 dpi than in the control group of animals. There was a statistically significant lower TXB₂ concentration in the eyes of immunocompetent infected mice compared with the noninfected group on 8 dpi. However, on 24 dpi, we noted statistically significant higher TXB₂ levels in the immunocompetent infected mice than in the control group. In immunocompromised mice, there was a lower TXB₂ level on 8 dpi than in control mice. This study confirmed the existence of an inflammatory process in the eyes of immunocompetent and immunocompromised mice infected with Acanthamoeba spp. without damaged corneas.

Adipocyte-derived PGE2 is required for intermittent fasting-induced Treg proliferation and improvement of insulin sensitivity

The intermittent fasting (IF) diet has profound benefits for diabetes prevention. However, the precise mechanisms underlying IF's beneficial effects remain poorly defined. Here, we show that the expression levels of cyclooxygenase-2 (COX-2), an enzyme that produces prostaglandins, are suppressed in white adipose tissue (WAT) of obese humans. In addition, the expression of COX-2 in WAT is markedly upregulated by IF in obese mice. Adipocyte-specific depletion of COX-2 led to reduced fractions of CD4+Foxp3+ Tregs and a substantial decrease in the frequency of CD206+ macrophages, an increase in the abundance of γδT cells in WAT under normal chow diet conditions, and attenuation of IF-induced antiinflammatory and insulin-sensitizing effects, despite a similar antiobesity effect in obese mice. Mechanistically, adipocyte-derived prostaglandin E2 (PGE2) promoted Treg proliferation through the CaMKII pathway in vitro and rescued Treg populations in adipose tissue in COX-2-deficient mice. Ultimately, inactivation of Tregs by neutralizing anti-CD25 diminished IF-elicited antiinflammatory and insulin-sensitizing effects, and PGE2 restored the beneficial effects of IF in COX-2-KO mice. Collectively, our study reveals that adipocyte COX-2 is a key regulator of Treg proliferation and that adipocyte-derived PGE2 is essential for IF-elicited type 2 immune response and metabolic benefits.

Efferocytosis and Its Role in Inflammatory Disorders

Efferocytosis is the effective clearance of apoptotic cells by professional and non-professional phagocytes. The process is mechanically different from other forms of phagocytosis and involves the localization, binding, internalization, and degradation of apoptotic cells. Defective efferocytosis has been demonstrated to associate with the pathogenesis of various inflammatory disorders. In the current review, we summarize recent findings with regard to efferocytosis networks and discuss the relationship between efferocytosis and different immune cell populations, as well as describe how efferocytosis helps resolve inflammatory response and modulate immune balance. Our knowledge so far about efferocytosis suggests that it may be a useful target in the treatment of numerous inflammatory diseases.

Th17 cells in the liver: balancing autoimmunity and pathogen defense

In addition to carcinogenesis, T helper 17 (Th17) cells (a subtype of CD4 + T lymphocytes) are involved in the acute, chronic, and cirrhotic phases of liver diseases; however, their role in the development and progression of liver diseases remains unclear. It is difficult to elucidate the role of Th17 cells in liver diseases due to their dichotomous nature, i.e., plasticity in terms of pathogenic or host protective function depending on environmental and time phase factors. Moreover, insufficient depletion of Th17 cells by inhibiting the cytokines and transcription factors involved in their production causes difficulties in analyzing their specific role in vitro and in vivo murine models, partially due to complex interaction. This review summarizes the recent progress in understanding the plasticity and function of hepatic Th17 cells and type 3 cytokines.

Human Oral Epithelial Cells Suppress T Cell Function via Prostaglandin E2 Secretion

The oral mucosa is constantly exposed to a plethora of stimuli including food antigens, commensal microbiota and pathogens, requiring distinct immune responses. We previously reported that human oral epithelial cells (OECs) suppress immune responses to bacteria, using H413 and TR146 OEC lines and primary OECs in co-culture with dendritic cells (DCs) and T cells (OEC-conditioned cells). OECs reduced DCs expression of CD80/CD86 and IL-12/TNFα release and impaired T cell activation. Here, we further evaluated the immunosuppression by these OECs and investigated the underlying mechanisms. OEC-conditioned DCs did not induce CD4 T cell polarization towards Treg, judging by the absence of FoxP3 expression. OECs also repressed T-bet/IFNγ expression in CD4 and CD8 T cells activated by DCs or anti-CD3/CD28 antibodies. This inhibition depended on OEC:T cell ratio and IFNγ repression occurred at the transcriptional level. Time-lapse experiments showed that OECs inhibited early steps of T cell activation, consistent with OECs inability to suppress T cells stimulated with PMA/ionomycin. Blocking CD40/CD40L, CD58/CD2 and PD-L1/PD-1 interactions with specific antibodies did not disrupt T cell suppression by OECs. However, preventing prostaglandin E2 (PGE2) synthesis or blocking PGE2 binding to the cognate EP2/EP4 receptors, restored IFNγ and TNFα production in OEC-conditioned T cells. Finally, treating OECs with poly(I:C), which simulates viral infections, limited T cell suppression. Overall, these results point to an inherent ability of OECs to suppress immune responses, which can nonetheless be eluded when OECs are under direct assault.

Roles of Eicosanoids in Regulating Inflammation and Neutrophil Migration as an Innate Host Response to Bacterial Infections

Eicosanoids are lipid-based signaling molecules that play a unique role in innate immune responses. The multiple types of eicosanoids, such as prostaglandins (PGs) and leukotrienes (LTs), allow the innate immune cells to respond rapidly to bacterial invaders. Bacterial pathogens alter cyclooxygenase (COX)-derived prostaglandins (PGs) in macrophages, such as PGE2 15d-PGJ₂, and lipoxygenase (LOX)-derived leukotriene LTB_4, which has chemotactic functions. The PG synthesis and secretion are regulated by substrate availability of arachidonic acid and by the COX-2 enzyme, and the expression of this protein is regulated at multiple levels, both transcriptionally and posttranscriptionally. Bacterial pathogens use virulence strategies such as type three secretion systems (T3SSs) to deliver virulence factors altering the expression of eicosanoid-specific biosynthetic enzymes, thereby modulating the host response to bacterial lipopolysaccharides (LPS). Recent advances have identified a novel role of eicosanoids in inflammasome activation during intracellular infection with bacterial pathogens. Specifically, PGE₂ was found to enhance inflammasome activation, driving the formation of pore-induced intracellular traps (PITs), thus trapping bacteria from escaping the dying cell. Finally, eicosanoids and IL-1β released from macrophages are implicated in the efferocytosis of neighboring neutrophils. Neutrophils play an essential role in phagocytosing and degrading PITs and associated bacteria to restore homeostasis. This review focuses on the novel functions of host-derived eicosanoids in the host-pathogen interactions.

The Effect of Lipid Metabolism on CD4+ T Cells

CD4⁺ T cells play a vital role in the adaptive immune system and are involved in the pathogenesis of many diseases, including cancer, autoimmune diseases, and chronic inflammation. As an important mechanism for energy storage, a lot of researches have clarified that metabolism imbalance interacts with immune disorder, and one leads to the other. Lipid metabolism has close relationship with CD4⁺ T cells. In this review, we discuss fatty acid, cholesterol, prostaglandin, and phospholipid metabolism in CD4⁺ T cell subsets. Fatty acid β-oxidation (FAO) is activated in Th17 cell to support the proinflammatory function. Cholesterol promotes Th1, Th2, and Treg cell differentiation. In addition to glucose metabolism, lipid metabolism is also very important for immunity. Here, it is highlighted that lipid metabolism regulates CD4⁺ T cell differentiation and function and is related to diseases.

Efferocytosis in health and disease

The clearance of apoptotic cells by professional and non-professional phagocytes - a process termed 'efferocytosis' - is essential for the maintenance of tissue homeostasis. Accordingly, defective efferocytosis underlies a growing list of chronic inflammatory diseases. Although much has been learnt about the mechanisms of apoptotic cell recognition and uptake, several key areas remain incompletely understood. This Review focuses on new discoveries related to how phagocytes process the metabolic cargo they receive during apoptotic cell uptake; the links between efferocytosis and the resolution of inflammation in health and disease; and the roles of efferocytosis in host defence. Understanding these aspects of efferocytosis sheds light on key physiological and pathophysiological processes and suggests novel therapeutic strategies for diseases driven by defective efferocytosis and impaired inflammation resolution.

Prostaglandin regulation of T cell biology

Prostaglandins (PG) are pleiotropic bioactive lipids involved in the control of many physiological processes, including key roles in regulating inflammation. This links PG to the modulation of the quality and magnitude of immune responses. T cells, as a core part of the immune system, respond readily to inflammatory cues from their environment, and express a diverse array of PG receptors that contribute to their function and phenotype. Here we put in context our knowledge about how PG affect T cell biology, and review advances that bring light into how specific T cell functions that have been newly discovered are modulated through PG. We will also comment on drugs that target PG metabolism and sensing, their effect on T cell function during disease, and we will finally discuss how we can design new approaches that modulate PG in order to maximize desired therapeutic T cell effects.

Innate immune cell-epithelial crosstalk during wound repair

Skin and intestinal epithelial barriers play a pivotal role in protecting underlying tissues from harsh external environments. The protective role of these epithelia is, in part, dependent on a remarkable capacity to restore barrier function and tissue homeostasis after injury. In response to damage, epithelial wounds repair by a series of events that integrate epithelial responses with those of resident and infiltrating immune cells including neutrophils and monocytes/macrophages. Compromise of this complex interplay predisposes to development of chronic nonhealing wounds, contributing to morbidity and mortality of many diseases. Improved understanding of crosstalk between epithelial and immune cells during wound repair is necessary for development of better pro-resolving strategies to treat debilitating complications of disorders ranging from inflammatory bowel disease to diabetes. In this Review we focus on epithelial and innate immune cell interactions that mediate wound healing and restoration of tissue homeostasis in the skin and intestine.

The in vitro and in vivo anti-inflammatory effect of osthole, the major natural coumarin from Cnidium monnieri (L.) Cuss, via the blocking of the activation of the NF-κB and MAPK/p38 pathways

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory condition of the intestines and is difficult to cure once diagnosed. The efficacy of the current clinical treatment for UC is limited. Common anti-inflammatory drugs are prone to adverse effects, while novel biological agents are expensive, although tolerated by patients. Therefore, an urgency exists to find more safe and effective drugs to treat UC. Osthole is an active constituent isolated from the fruit of Cnidium monnieri (L.) Cuss. Osthole has anti-inflammatory activities and offers certain intestinal protection. These characteristics indicate that osthole has the potential to inhibit UC.

PURPOSE

The study was conducted to investigate the anti-inflammatory potential of osthole in LPS-induced RAW 264.7 cells and dextran sulphate sodium (DSS)-induced ulcerative colitis in mice.

METHODS

In in vitro experiments, mouse monocyte-macrophage RAW 264.7 cells were stimulated by 1 μg/ml LPS to produce inflammatory mediators. Griess reagent was used to determine Nitric Oxide (NO) production, and ELISA kits were used to determine the levels of PGE_2, TNF-α, and IL-6. The anti-inflammatory mechanisms of osthole were detected using western blot. In in vivo experiments, UC was induced via the intragastric administration of 3.5% DSS to BALB/C mice for 7 days. During the experiment, clinical signs and body weight were monitored and recorded daily to calculate the DAI score. At the end of the experiment, the colon lengths were measured. The colonic histopathological lesions were evaluated. MPO activity and TNF-α levels were determined using the corresponding kits. The protein expression of TNF-α and NF-κB pathways were analysed using western blot.

RESULTS

In an in vitro study, osthole inhibited the production of NO, PGE2, TNF-α, and IL-6 in LPS-induced RAW 264.7 cells. The results of western blot showed that osthole inhibited the expression of iNOS, COX-2, p38 MAPK and IκB α in RAW 264.7 cells. On this basis, in DSS-induced UC mice, it was found that osthole relieved the symptoms of UC by inhibiting weight loss, colon shortening and the DAI score, and simultaneously alleviating colon tissue lesions. It was also found that osthole reduced the levels of TNF-α in serum and colon tissues and effectively inhibited the activity of MPO. The western blot results showed that osthole reduced the expression of NF-κB p65 and p-IκB α and increased the content of IκB α in colon tissues.

CONCLUSION

Osthole exerted anti-inflammatory effects by blocking the activation of the NF-κB and MAPK/p38 pathways. Additionally, osthole possesses therapeutic potential in the treatment of UC.