RNA-seq reveals inflammation-linked pathways and muscle atrophy in ventilator-induced diaphragmatic dysfunction in rats
Background
Mechanical ventilation, while life-saving, can paradoxically lead to ventilator-induced diaphragmatic dysfunction (VIDD), a severe complication causing prolonged weaning and chronic respiratory issues in survivors. Currently, no effective treatments exist to prevent this loss of diaphragmatic function. Understanding the underlying molecular mechanisms, particularly inflammation-linked signaling pathways, is critical to identify novel therapeutic targets and address this significant clinical gap, improving outcomes for intensive care unit patients.
Study Design
Adult male Wistar rats were divided into three groups (n=3 per group): a control (0 h) group, a 6-hour controlled mechanical ventilation (CMV 6 h) group, and a 12-hour controlled mechanical ventilation (CMV 12 h) group. Diaphragmatic tissues were collected for pathological assessment using hematoxylin-eosin (HE) staining to quantify myofiber cross-sectional area (CSA) and immunohistochemistry to detect MHCslow and MHCfast myosin heavy chain isoforms. Transcriptome sequencing (RNA-Seq) was performed to analyze mRNA expression changes, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses.
Results
Pathological analysis revealed significant diaphragmatic muscle fiber atrophy and varying degrees of inflammatory cell infiltration in both CMV groups. Quantitative HE staining showed myofiber CSA was significantly reduced in the CMV 6 h group (P < 0.05) and further reduced in the CMV 12 h group (P < 0.01) compared to controls. Immunohistochemistry indicated no significant difference in MHCslow and MHCfast expression at 6 h (P > 0.05), but a significant reduction in the percentage of positive area for both MHCslow and MHCfast was observed in the CMV 12 h group (P < 0.05). RNA-Seq identified substantial gene expression changes: > In the CMV 6 h group, 2,048 differentially expressed genes (DEGs) were found (321 upregulated, 1,727 downregulated) (P < 0.05). The CMV 12 h group showed 1,495 DEGs (P < 0.05), with GO and KEGG analyses pointing to the involvement of inflammation-linked signaling pathways in VIDD pathogenesis.
Key Findings
- Diaphragmatic muscle fiber atrophy and inflammatory cell infiltration observed in CMV-treated rats.
- Myofiber cross-sectional area significantly reduced at 6h (P<0.05) and 12h (P<0.01) of CMV.
MHCslowandMHCfastexpression significantly reduced at 12h of CMV (P<0.05).RNA-Seqidentified 2,048 differentially expressed genes at 6h CMV and 1,495 DEGs at 12h CMV.- Inflammation-linked signaling pathways were implicated in VIDD pathogenesis by
GOandKEGGanalyses.
Why It Matters
This study provides crucial insights into the molecular underpinnings of ventilator-induced diaphragmatic dysfunction (VIDD), highlighting the central role of inflammation and specific gene expression changes. Identifying these key genes and inflammatory pathways offers promising new targets for therapeutic intervention, which is critical given the current lack of effective treatments for VIDD. While preclinical, this research lays the groundwork for developing novel strategies to prevent or mitigate diaphragmatic damage in mechanically ventilated patients, potentially reducing weaning times and improving long-term respiratory outcomes. Future research could focus on validating these specific pathways and genes to translate these findings into clinically usable protocols or drug candidates.
ventilator-induced diaphragmatic dysfunction
VIDD
inflammation
rna-seq
preclinical-animal
rat