Changes in the host transcriptome and microbial metatranscriptome of the ileum of dairy calves subjected to artificial dosing of exogenous rumen contents

Development of a properly functioning gastrointestinal tract (GIT) at an early age is critical for the wellbeing and lifetime productivity of dairy cattle. The role of early microbial colonization on GIT development in neonatal cattle and the associated molecular changes remain largely unknown, particularly for the small intestine. In this study, we performed artificial dosing of exogenous rumen fluid during the early life of the calf, starting at birth through the weaning transition at 8 wk. Six calves were included in this study. At 8 wk of age, tissue from the ileum was collected and subjected to host transcriptome and microbial metatranscriptome analysis using RNA sequencing. A total of 333 genes showed significant differential expression (DE) (fold-change ≥2; adjusted P < 0.1, mean read-count ≥10) between the treated and control calves. Gene ontology analysis indicated that these DE genes are predominantly associated with processes related to the host immune response (P < 0.0001). Association analysis between the host gene expression and the microbial genus abundance identified 57 genes as having significant correlation with the ileum microbial genera (P < 0.0001). Of these, three genes showed significant association with six microbial genera: lysozyme 2 (LYZ2), fatty acid binding protein 5 (FABP5), and fucosyltransferase (FUT1). Specifically, the profound increase in expression of LYZ2 in treated calves suggests the initiation of antibacterial activity and innate response from the host. Despite the limitation of a relatively small sample size, this study sheds light on the potential impact of early introduction of microbes on the small intestine of calves.

The Impact of Resveratrol on Oxidative Stress Induced by Methotrexate in Rat Ileum Tissue: Evaluation of Biochemical and Histopathological Features and Analysis of Gene Expression

OBJECTIVE

The aim of this study was to assess the impact of resveratrol (RST) on oxidative stress induced by methotrexate in rat ileum tissue.

MATERIALS AND METHODS

Twenty-four rats were divided into 4 groups with 6 in each group. Each rat was orally administered the following every day for 30 days: group 1 (MTXG), methotrexate (MTX; 5 mg/kg); group 2 (RMTXG), MTX (5 mg/kg) plus RST (25 mg/kg/day); group 3 (RSTG), RST alone (25 mg/kg/day), and group 4 (controls), distilled water. After the rats had been sacrified, the ilea were removed for the assessment of malondialdehyde (MDA), total glutathione (tGSH) and glutathione peroxidase (GSH-Px). Gene expression analyses for interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and myeloperoxidase (MPO) were also performed. Hematoxylin and eosin-stained paraffin-embedded sections of the ileum were analyzed under a light microscope and the findings were recorded. Statistical analyses of the data were performed using one-way ANOVA.

RESULTS

The administration of MTX in group 1 yielded a higher level of MDA (8.33 ± 2.5 μmol/g protein, p < 0.001) and lower levels of tGSH (0.97 ± 0.29 nmol/g protein) and GSH-Px (5.22 ± 0.35 U/g protein, p < 0.001) compared to the other groups. MTX also increased IL-1β (40.33 ± 5.43 gene expression levels), TNF-α (6.08 ± 0.59) and MPO gene expression (9 ± 1.41) in group 1 compared to the controls (11.33 ± 2.07, 2.15 ± 0.33 and 3.43 ± 0.48, respectively, p < 0.001). The impact of RST on IL-1β, TNF-α and MPO gene expression induced by MTX was observed as a reversal of these findings (p < 0.05). Severe inflammation, damage to the villus epithelium and crypt necrosis was observed histopathologically in the MTXG group, whereas only mild inflammation was seen in the RMTXG group.

CONCLUSION

In this study, ileal damage caused by MTX was inhibited by RST.