Effect of High Calorie Diet on Intestinal Flora in LPS-Induced Pneumonia Rats

Abstract

Intestinal flora plays an important role in inflammatory response to systemic or local organs of its host. High calorie diet has been shown to aggravate the condition of pneumonia and delay recovery, especially in children. However, the underlying mechanisms remain unclear. This study placed SPF rats in a conventional environment, high calorie diet or LPS atomization was performed respectively or combined. Analysis of high-throughput sequencing of intestinal content combined with animal weight, organ index, serum inflammatory factors indicators and bioinformatics found that after pulmonary infection combined with a high-calorie diet, rats showed significant changes such as weight loss and increased lung weight index, and their lung and intestinal tissues showed more obvious inflammatory changes. And its gut flora structure suggests, the abundance of Leuconostocaceae in significantly reduced; abundance of Staphylococcus, Planococcaceae, Staphylococcus, Staphylococcaceae, Bacillales, Gemellales and Aerococcus significant increased. The study showed that high calorie diet and LPS atomization synergistically promoted pneumonia process in rat pups, which is related to changes in structure of intestinal flora. It is worth noting that pneumonia rats fed by convention diet also causing intestinal flora imbalance.

Figure 1

Changes in physical signs of rats with high calorie feed and pneumonia. (A) Weight, (B) abdominal circumference, (C) rectal temperature, (D) axillary temperature, (E) organ coefficient, (F) lung.

Figure 2

Changes in tissues of rats with high calorie feed and pneumonia. (A) HE staining of intestine and lung; (B) serum motilin, gastrin; (C) serum inflammatory factor; (D) recognition receptor of pathway protein in intestinal tissue pattern. From left to right: NC, MC1, MC2, MC3.

Figure 3

OTU division of intestinal content microecology. (A) Sequence length distribution; (B) Venn diagram of shared OTU; (C) sparse curve of OTU number; (D) accumulation curve of specaccum species; (E) abundance grade curve; (F) microbial number statistics of each classification level.

Figure 4

Micro-ecological structure of intestinal contents. (A) Group-to-group difference classification unit display map based on classification level tree (NC-MC1); (B) group-to-group difference classification unit display map based on classification level tree (NC-MC2); (C) group-to-group difference classification unit display map based on classification level tree (NC-MC3); (D) group-to-group difference classification unit display map based on classification level tree (MC1-MC3); (E) group-to-group difference classification unit display map based on classification level tree (MC2-MC3); (F) overall classification level tree diagram based on GrabhlAn sample.

Figure 5

Micro-ecological factors of intestinal contents. (A) Three-dimensional sorting map samples of PCA analysis; (B) three-dimensional sorting map samples of Unweighted UniFrac PCoA analysis; (C) three-dimensional sorting map samples of Weighted UniFrac PCoA analysis; (D) PLS-DA discriminant analysis chart; (E) RDA constraint sorting chart; (F) associated network diagram of dominant genus.

Figure 6

Prediction of metabolic function of intestinal contents. (A) Predicted second level distribution diagram of KEGG by KERUSt; (B) Venn map of common function group; C: KEGG orthologous gene cluster (KO) abundance heat map combined with cluster analysis.

Figure 7

Pathological biological network construction of high calorie diet combined with pneumonia. (A) Protein interaction based on string analysis; (B) cluster based on mcode analysis (score = 6.75, enrichment is proportional to node shading); (C) Enrichment result of Intestinal immune network for IgA production pathway (red star is enrichment protein, degree of protein enrichment is inversely proportional to color shade); (D) Enrichment results of NOD-like receptor signaling pathway (red star is enrichment protein, degree of protein enrichment is inversely proportional to color shade).

Figure 8

Whether a high-calorie diet affects respiratory tract infections through intestinal flora.