Abstract
This study aimed to determine the expression of nuclear factor kappa B (NF-κB) pathway related miRNAs in experimental acute respiratory distress syndrome (ARDS) induced by lipopolysaccharide (LPS) in rats, and to elucidate the underlying molecular mechanism. Twenty four sprague dawley rats were randomly divided into two groups; LPS (n = 12) and control (n = 12). Experimental ARDS was induced by intraperitoneal injection of E. coli LPS in LPS group. Intraperitoneal saline was administered in control group. Serum and lung samples were collected from both groups. Immunohistochemistry staining was performed for interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), CD 68, and caspase-3 in lung samples. Intensity of staining was scored as strong, moderate, weak, and no for evaluation of IL-1β and TNF-α. In addition, caspase-3 and CD68-positive stained cells were counted in sections. Expressions of 9 miRNAs were determined by quantitative real-time PCR in serum samples. IL-1β and TNF-α staining scores were significantly higher in the LPS group in comparison with the control group (P = 0.04 and P = 0.02, respectively). In addition, caspase-3 and CD68-positive stained cells were significantly higher in the LPS group (P = 0.02). Expressions of seven miRNAs were significantly changed in the LPS group in comparison with the control group. While six miRNAs (miR-7a-5p, miR-7b, miR-9a-5p, miR-21-5p, miR-29a-3p, and miR-138-5p) were up regulated, only miR-124-3p was down regulated. This study suggests that these miRNAs may have a role in the pathogenesis of ARDS related to NF-κB. However, this relationship needs to be examined in new studies by evaluation of pathways and target genes.