Lung Edema and Mortality Induced by Intestinal Ischemia and Reperfusion Is Regulated by VAChT Levels in Female Mice

Emodin alleviates intestinal ischemia-reperfusion injury through antioxidant stress, anti-inflammatory responses and anti-apoptosis effects via Akt-mediated HO-1 upregulation

BACKGROUND

Intestinal ischemia-reperfusion (I/R) injury is a severe vascular emergency. Previous research indicated the protective effects of Emodin on I/R injury. Our study aims to explore the effect of Emodin on intestinal I/R (II/R) injury and elucidate the underlying mechanisms.

METHODS

C57BL/6 mice and Caco-2 cells were used for in vivo and in vitro studies. We established an animal model of II/R injury by temporarily occluding superior mesenteric artery. We constructed an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model using a hypoxia-reoxygenation incubator. Different doses of Emodin were explored to determine the optimal therapeutic dose. Additionally, inhibitors targeting the protein kinase B (Akt) or Heme oxygenase-1 (HO-1) were administered to investigate their potential protective mechanisms.

RESULTS

Our results demonstrated that in animal experiments, Emodin mitigated barrier disruption, minimized inflammation, reduced oxidative stress, and inhibited apoptosis. When Akt or HO-1 was inhibited, the protective effect of Emodin was eliminated. Inhibiting Akt also reduced the level of HO-1. In cell experiments, Emodin reduced inflammation and apoptosis in the OGD/R cell model. Additionally, when Akt or HO-1 was inhibited, the protective effect of Emodin was weakened.

CONCLUSIONS

Our findings suggest that Emodin may protect the intestine against II/R injury through the Akt/HO-1 signaling pathway.

Effect of VAChT reduction on lung alterations induced by exposure to iron particles in an asthma model

INTRODUCTION

Pollution harms the health of people with asthma. The effect of the anti-inflammatory cholinergic pathway in chronic allergic inflammation associated to pollution is poorly understood.

METHODS

One hundred eight animals were divided into 18 groups (6 animals). Groups included: wild type mice (WT), genetically modified with reduced VAChT (VAChTKD), and those sensitized with ovalbumin (VAChTKDA), exposed to metal powder due to iron pelletizing in mining company (Local1) or 3.21 miles away from a mining company (Local2) in their locations for 2 weeks during summer and winter seasons. It was analyzed for hyperresponsivity, inflammation, remodeling, oxidative stress responses and the cholinergic system.

RESULTS

During summer, animals without changes in the cholinergic system revealed that Local1 exposure increased the hyperresponsiveness (%Rrs, %Raw), and inflammation (IL-17) relative to vivarium animals, while animals exposed to Local2 also exhibited elevated IL-17. During winter, animals without changes in the cholinergic system revealed that Local2 exposure increased the hyperresponsiveness (%Rrs) relative to vivarium animals. Comparing the exposure local of these animals during summer, animals exposed to Local1 showed elevated %Rrs, Raw, and IL-5 compared to Local 2, while in winter, Local2 exposure led to more IL-17 than Local1. Animals with VAChT attenuation displayed increased %Rrs, NFkappaB, IL-5, and IL-13 but reduced alpha-7 compared to animals without changes in the cholinergic system WT. Animals with VAChT attenuation and asthma showed increased the hyperresponsiveness, all inflammatory markers, remodeling and oxidative stress compared to animals without chronic lung inflammation. Exposure to Local1 exacerbated the hyperresponsiveness, oxidative stressand inflammation in animals with VAChT attenuation associated asthma, while Local2 exposure led to increased inflammation, remodeling and oxidative stress.

CONCLUSIONS

Reduced cholinergic signaling amplifies lung inflammation in a model of chronic allergic lung inflammation. Furthermore, when associated with pollution, it can aggravate specific responses related to inflammation, oxidative stress, and remodeling.

Acute Lung Injury in Cholinergic-Deficient Mice Supports Anti-Inflammatory Role of α7 Nicotinic Acetylcholine Receptor

(1) Background: The lung cholinergic pathway is important for controlling pulmonary inflammation in acute lung injury, a condition that is characterized by a sudden onset and intense inflammation. This study investigated changes in the expression levels of nicotinic and muscarinic acetylcholine receptors (nAChR and mAChR) in the lung during acute lung injury. (2) Methods: acute lung injury (ALI) was induced in wild-type and cholinergic-deficient (VAChT-KD^HOM) mice using intratracheal lipopolysaccharide (LPS) instillation with or without concurrent treatment with nicotinic ligands. Bronchoalveolar lavage fluid was collected to evaluate markers of inflammation, and then the lung was removed and processed for isolation of membrane fraction and determination of acetylcholine receptors level using radioligand binding assays. (3) Results: LPS-induced increase in lung inflammatory markers (e.g., neutrophils and IL-1β) was significantly higher in VAChT-KD^HOM than wild-type mice. In contrast, LPS treatment resulted in a significant increase in lung’s α7 nicotinic receptor level in wild-type, but not in VAChT-KD^HOM mice. However, treatment with PNU 282987, a selective α7 nicotinic receptor agonist, restored VAChT-KD^HOM mice’s ability to increase α7 nicotinic receptor levels in response to LPS-induced acute lung injury and reduced lung inflammation. LPS also increased muscarinic receptors level in VAChT-KD^HOM mice, and PNU 282987 treatment reduced this response. (4) Conclusions: Our data indicate that the anti-inflammatory effects of the lung cholinergic system involve an increase in the level of α7 nicotinic receptors. Pharmacological agents that increase the expression or the function of lung α7 nicotinic receptors have potential clinical uses for treating acute lung injury.