Naringin attenuates Actinobacillus pleuropneumoniae-induced acute lung injury via MAPK/NF-κB and Keap1/Nrf2/HO-1 pathway

Actinobacillus pleuropneumoniae (APP) causes porcine pleuropneumonia (PCP), which is clinically characterized by acute hemorrhagic, necrotizing pneumonia, and chronic fibrinous pneumonia. Although many measures have been taken to prevent the disease, prevention and control of the disease are becoming increasingly difficult due to the abundance of APP sera, weak vaccine cross-protection, and increasing antibiotic resistance in APP. Therefore, there is an urgent need to develop novel drugs against APP infection to prevent the spread of APP. Naringin (NAR) has been reported to have an excellent therapeutic effect on pulmonary diseases, but its therapeutic effect on lung injury caused by APP is not apparent. Our research has shown that NAR was able to alleviate APP-induced weight loss and quantity of food taken and reduce the number of WBCs and NEs in peripheral blood in mice; pathological tissue sections showed that NAR was able to prevent and control APP-induced pathological lung injury effectively; based on the establishment of an in vivo/in vitro model of APP inflammation, it was found that NAR was able to play an anti-inflammatory role through inhibiting the MAPK/NF-κB signaling pathway and exerting anti-inflammatory effects; additionally, NAR activating the Nrf2 signalling pathway, increasing the secretion of antioxidant enzymes Nqo1, CAT, and SOD1, inhibiting the secretion of oxidative damage factors NOS2 and COX2, and enhancing the antioxidant stress ability, thus playing an antioxidant role. In summary, NAR can relieve severe lung injury caused by APP by reducing excessive inflammatory response and improving antioxidant capacity.

Naringin alleviates pneumonia caused by Klebsiella pneumoniae infection by suppressing NLRP3 inflammasome

Klebsiella pneumoniae (Kpn) is an important pathogen of hospital-acquired pneumonia, which can lead to sepsis and death in severe cases. In this study, we simulated pneumonia induced by Kpn infection in mice to investigate the therapeutic effect of naringin (NAR) on bacterial-induced lung inflammation. Mice infected with Kpn exhibited increases in white blood cells (WBC) and neutrophils in the peripheral blood and pathological severe injury of the lungs. This injury was manifested by increased expression of the inflammatory cytokines interleukin (IL)- 18, IL-1β, tumor necrosis factor-α (TNF-α) and IL-6, and elevated the expression of NLRP3 protein. NAR treatment could decrease the protein expression of NLRP3, alleviate lung inflammation, and reduce lung injury in mice caused by Kpn. Meanwhile, molecular docking results suggest NAR could bind to NLRP3 and Surface Plasmon Resonance (SPR) analyses also confirm this result. In vitro trials, we found that pretreated with NAR not only inhibited nuclear translocation of nuclear factor (NF)-κB protein P65 but also attenuated the protein interaction of NLRP3, caspase-1 and ASC and inhibited the assembly of NLRP3 inflammasome in mice AMs. Additionally, NAR could reduce intracellular potassium (K+) efflux, inhibiting NLRP3 inflammasome activation. These results indicated that NAR could protect against Kpn-induced pneumonia by inhibiting the overactivation of the NLRP3 inflammasome signaling pathway. The results of this study confirm the efficacy of NAR in treating bacterial pneumonia, refine the mechanism of action of NAR, and provide a theoretical basis for the research and development of NAR as an anti-inflammatory adjuvant.

[The relationship between acid reflux and esophageal motility, esophagitis and cardiac morphology in gastroesophageal reflux disease]

Objective: To analyze the relationship between the severity of esophageal acid reflux and esophageal motility, esophageal mucosal injury and morphological anatomy of gastroesophageal junction (GEJ) in patients with gastroesophageal reflux disease (GERD). Methods: The clinicaldata of GERD patients who underwent 24 h pH-impedance monitoring, gastroscopy and high-resolution manometry (HRM) from January 2016 to January 2019 in the Gastroesophageal Surgery Department of PLA Rocket Force Characteristic Medical Center were retrospectively analyzed. The patients were divided into non-pathological acid reflux group, mild pathological acid reflux group and moderate to severe pathological acid reflux group according to the DeMeester score. The gender and age of each group were matched, with 60 cases in each group. Statistical analysiswas performed to analyze thedifferences in upper esophageal sphincter pressure, lower esophageal sphincter pressure (LES), LES length, length of ventral LES, percentage of ineffective swallowing, esophagitis, Hill grade of GEJ, and hiatus hernia (HH) in each group. The comparison and correlation analysis are also carried out between the groups. Results: The male-female ratio was 33/27, and the age was (57±13) years in each group. Non-parametric analysis showed that the LES pressure and the length of the ventral LES decreased with the severity of acid reflux, and there was a statistical difference (P= 0.033, P=0.015). The detection rate of HH by HRM increased significantly (χ(2)=0.001) as well. Esophagitis score increased with the severity of acid reflux and there was statistical difference (P<0.001).The detection rate of esophagitis increased significantly (χ(2)<0.001) as well. Hill grading score of GEJ increased with the severity of acid reflux, and there was statistical difference (P<0.001).The detection rate of HH by endoscopy increased significantly (χ(2)<0.001) as well. The correlation between DeMeester score and LES pressure, length of ventral LES, percentage of ineffective swallowing, esophagitis score, and Hill grade score were statistically significant (P<0.05). Conclusions: The esophageal low motility (such as low LES pressure) and anatomical abnormalities (abdominal esophageal shortening, GEJ flabbiness, and even HH formation) of the GEJ regionare significantly associated with the severity of acid reflux. These factors may be important causes of increased acid reflux. In addition, the aggravation of acid reflux can also increase the incidence and severity of esophagitis.

[Relationship between the severity of reflux esophagitis and the esophageal motility features on high resolution manometry]

Objective: To analyze esophageal motility dysfunction in gastroesophageal reflux disease (GERD) with different severity of esophagitis, and the relationship between the esophageal motility dysfunction and the severity of esophagitis. Methods: GERD patients simultaneously undergone endoscopy and high-resolution manometry were divided into four groups: Non-esophagitis (Non-erosive gastroesophageal reflux disease, NERD) group, mild esophagitis group, moderate esophagitis group and severe esophagitis group. The gender and age were matched for each group, and every group consisted of 80 cases. Nonparametric test was used to analyze the differences in HRM parameters, such as upper esophageal sphincter (UES) pressure, lower esophageal sphincter (LES) pressure, LES length, LES-CD (crural diaphragm) separation distance, and the percentage of failed peristalsis of the four groups, and the differences between each two of the groups were also analyzed. Results: Nonparametric test showed that the LES pressure and length decreased with the severity of esophagitis, and there were statistical differences (P<0.001, P=0.030). The failed peristalsis percentage increased with the severity of esophagitis and the difference was statistically significant (P<0.001). The LES-CD separation distance was increased with the severity of esophagitis and had statistically significance (P<0.001). When comparing the differences between each two of the groups, there were significant differences (P<0.001, P=0.012, P<0.001, P<0.001) between NERD group and severe esophagitis group in the HRM parameters of the lower esophageal sphincter pressure, the LES length, the LES-CD separation distance, and the percentage of ineffective swallowing in the NERD and severe esophagitis group. The detection rate of HH was significantly increased from NERD to severe esophagitis, the detection rate of HH was 6.3% to 82.5% in gastoracopy and 16.3% to 45.0% in HRM, and the diagnostic consistency was fair (Kappa Value: 0.31). Conclusions: Hypo-dynamic state of esophageal and HH are the main motility characteristics of erosive gastroesophageal reflux disease, Esophageal motility abnormalities increase in parallel with the severity of GERD from NERD to severe esophagitis, these motility disorders may also play important roles in causing esophagitis.

EVALUATION OF THE ACUTE AND SUBCHRONIC TOXICITY OF Aster tataricus L. F

BACKGROUND

Aster tataricus L. f. is used as a traditional Chinese drug to relieve cough and asthma symptoms and to eliminate phlegm. However, Aster tataricus L. f. possesses toxicity, and little systematic research has been conducted on its toxic effects in the laboratory.

METHODS AND MATERIALS

The acute group was administered 75% alcohol extract of Aster tataricus L. f. in a single dose. A subchronic toxicity study was performed via daily oral administration of Aster tataricus L. f. at a dose of 0.34 g/kg body weight in SD rats. The rats were divided into six groups: a petroleum ether extract (PEA) group, an ethyl acetate extract (EEA) group, an n-butyl alcohol extract (NEA) group, a remaining lower aqueous phases (REA) group, a 75% alcohol extract (AEA) group and a control group. Quantitative measurements of cytokines were obtained by fluorescence with a laser scanner using a Cy3 equivalent dye.

RESULTS

The LD₅₀ of the 75% alcohol extract of Aster tataricus L. f. was 15.74 g/kg bw. In the subchronic toxicity study, no significant differences were observed among groups in relative organ weights, urine traits, liver antioxidase levels, or cytokine levels. However, significant sporadic differences were observed in body weight gains, haematology indices, biochemistry values, and histopathology features in PEA, EEA group. In addition, sporadic changes in other groups in measures such as WBC, MCHC, CK, ALP, AST, ALT, LDH, T-BIL, LDL-C, HDL-C, and TC were observed.

CONCLUSION

The toxicity study showed that Aster tataricus L. f. can produce toxic effects, mainly on the liver; much less on the heart. The LD₅₀ was 15.74 g/kg BW in mice, and the subchronic toxicity study, used a dosage of 0.34 g/kg/d.BW, showed that the toxic components of Aster tataricus L. f. were mainly concentrated in the petroleum ether fraction, followed by the ethyl acetate fraction, the n-butyl alcohol fraction, the lower aqueous phase and the 75% ethanol extracts. Abbreviations: PEA, petroleum ether extract of Aster tataricus L. f.; EEA, ethyl acetate extract of Aster tataricus L. f.; NEA: n-butyl alcohol extract of Aster tataricus L. f.; REA: lower aqueous phases of Aster tataricus L. f.; AEA, 75% alcohol extract of Aster tataricus L. f.; WBC, white blood cell; RBC, red blood cell, PLT, platelet; HCT, haematocrit; MCV, mean corpuscular volume; HGB, haemoglobin; MCH, mean corpuscular haemoglobin; MCHC, mean corpuscular haemoglobin concentration; CREA, creatinine; LDH, lactate dehydrogenase; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; T-BIL, total bilirubin; ALT, alanine aminotransferase; ALP, alkaline phosphatase; AST, aspartate aminotransferase; TP, total protein; ALB, albumin; Glu, glucose; TC, total cholesterol; TG, triglycerides; CK, creatine kinase; GSH, Glutathione; MDA, malondialdehyde; T-SOD, total superoxide dismutase; TNF, tumour necrosis factor; IFN, interferon; MCP, monocyte chemotactic protein C.