Effect of intestinal microbiota on lung injury in mice with acute necrotizing pancreatitis
10.3760/cma.j.cn115667-20240430-00087
- VernacularTitle:肠道菌群对急性坏死性胰腺炎小鼠肺损伤的影响
- Author:
Mengqi ZHAO
1
;
Mengyan CUI
;
Miaoyan FAN
;
Yingying LU
;
Qiaoli JIANG
Author Information
1. 上海交通大学医学院附属第一人民医院嘉定医院消化内科，上海 201803
- Publication Type:Journal Article
- Keywords:
Pancreatitis, acute necrotizing;
Lung injury;
Pyroptosis;
Intestinal microbiota
- From:
Chinese Journal of Pancreatology
2025;25(2):126-133
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the effects and possible mechanism of intestinal microbiota on lung injury in mice with acute necrotizing pancreatitis (ANP).Methods:The experimental mice were randomly assigned to normal control group (CON group), ANP model group (ANP group) and intestinal germ-free group (ABX group), with 6 mice in each group. The ANP mouse model was constructed by intraperitoneal injection of caerulein (100 μg/kg, for 10 times) at an interval of 1 hour each time, followed by 10 mg/kg lipopolysaccharide injection. Mice in ABX group were treated by Abx solution (0.5 g/L vancomycin, 1 g/L neomycin, 1 g/L metronidazole, and 1 g/L ampicillin), 1 ml/100 g gavage for 28 days before preparation of the ANP model. The CON group was injected intraperitoneally with an equal volume of PBS. Histopathologic examination of the pancreas, lungs, and terminal ileum was routinely performed. Serum amylase levels were measured using enzymatic kinetic chemistry, and serum diamine oxidase (DAO) and lung tissue myeloperoxidase (MPO) activities were measured using ELISA assay. Expression of inflammatory factors, pyroptosis-related molecules in lung tissue and intestinal epithelial tight junction proteins was detected by fluorescence quantitative PCR. Western blotting was used to detect the expression of the pyroptosis molecules caspase-1 and GSDMD in lung tissue, and intestinal epithelial tight junction proteins. Changes of bacterial distribution in lung tissue were measured by fluorescence in situ hybridization. Results:The pathological scores of pancreatic tissue of CON, ANP, and ABX group were (0.67±0.26), (7.33±0.82), and (5.67±0.81); the pathological scores of lung tissue were (1.67±0.41), (5.67±0.41), and (3.58±0.58); the pathological scores of ileal tissue were (0.58±0.52), (3.83±0.75), and (4.33±0.82); the serum amylase levels were (403.95±93.11), (1037.24±126.77), and (647.32±145.90)U/L; the MPO levels in lung tissue were (0.23±0.03), (0.63±0.09), and (0.48±0.05)U/g. ABX group had significantly lower scores in pancreatic and lung tissues, serum amylase levels, and MPO levels in lung tissue compared to ANP group, and all the differences were statistically significant (all P value <0.05). The expression level in pancreatis tissue from CON, ANP and ABX group of IL-1β mRNA was 1.84±0.90, 36.26±5.56 and 16.65±6.43, IL-6 mRNA was 1.07±0.15, 2.90±0.42 and 1.34±0.62, TNF-α mRNA was 0.47±0.11, 0.76±0.11 and 0.46±0.07, HMGB1 mRNA was 0.38±0.02, 0.72±0.22 and 0.44±0.08, caspase-1 mRNA was 1.07±0.18, 2.04±0.31 and 0.85±0.54, ASC mRNA was 1.24±0.19, 5.68±0.41 and 3.89±1.47, GSDMD mRNA was 0.79±0.17, 0.94±0.14 and 0.61±0.08, IL-18 mRNA was 0.83±0.27, 4.17±0.79 and 3.57±0.03, respectively. The expression of IL-1β, IL-6, TNF-α, HMGB1, caspase-1, ASC, and IL-18 mRNA in lung tissue was significantly increased in ANP group compared to the CON group; conversely, ABX group showed a significant decrease in the expression of these markers compared to ANP group; and all the differences were statistically significant (all P values <0.05). The protein level of caspase-1 in lung tissue of CON, ANP and ABX group was 1.59±0.51, 2.28±0.13, 1.38±0.47, and that of GSDMD was 1.90±0.09, 2.20±0.07 and 1.76±0.27, respectively, which in ANP group were significantly higher than in CON group, but in ABX group was significantly lower than in ANP group, and all the differences were statistically significant (all P values <0.05). The serum DAO levels of CON, ANP, and ABX group were (0.06±0.15), (0.52±0.11) and (0.58±0.11) ng/ml; the expression level of ileum tissue of claudin1 mRNA and protein was 0.98±0.26, 0.42±0.18, 0.32±0.24 and 1.05±0.08, 0.82±0.09, 0.19±0.04; occludin mRNA and protein was 0.91±0.07, 0.31±0.05, 0.32±0.14 and 1.03±0.07, 0.61±0.04, 0.64±0.11; ZO-1 mRNA and protein was 1.01±0.08, 0.80±0.28, 0.60±0.28, and 0.86±0.10, 0.99±0.30, 0.62±0.30. The serum DAO level was significantly elevated in both ANP and ABX groups compared to the CON group. The mRNA and protein expression of claudin-1 and occludin in both ANP and ABX groups were significantly lower than those in CON group; the expression of claudin-1 in ABX group was significantly downregulated compared to ANP group; and all the differences were statistically significant (all P values <0.05). The relative fluorescence intensities of lung tissue in CON, ANP, and ABX groups were 0.03±0.01, 0.06±0.01, and 0.04±0.01, respectively, which in ANP group was significantly higher compared to CON group, but in ABX group was significantly lower than ANP group; all the differences were statistically significant (all P values <0.05). Conclusions:Intestinal microbiota may attenuate acute pancreatitis-associated acute lung injury by inhibiting the pyroptosis pathway in lung tissue.
