Association between miR-126, miR-21, inflammatory factors and T lymphocyte apoptosis in septic rats

MicroRNAs (miRs) serve an important role in regulating expression levels of inflammatory factors but the underlying mechanism is still unclear. The present study aimed to observe miR-126 and miR-21 expression and apoptosis in T lymphocytes and to analyze their association with cytokine release in septic rats. The septic model rats were given intraperitoneal lipopolysaccharide (LPS) and divided into 0, 12, 24, 48 and 72 h groups. Peripheral blood was collected from each group to isolate T lymphocytes. The expression levels of miR-126 and miR-21 in T lymphocytes were observed, as well as cytokine release and apoptosis. Finally, the association between miR-126, miR-21, cytokines and apoptosis in T lymphocytes was analyzed. The release of TNF-α and IL-6 in septic rats was initially elevated but then decreased. miR-126 and miR-21 levels in T lymphocytes in septic rats were lower than those of NC rats. miR-126 and miR-21 initially decreased and then increased, whereas of apoptosis of T lymphocytes increased and then decreased, in septic rats. The expression of miR-126 was positively correlated with that of miR-21 (r=0.316; P=0.029) and negatively correlated with that of TNF-α (r=-0.480; P=0.001) and IL-6 (r=-0.626; P<0.001), as well as the apoptotic rate of T lymphocytes (r=-0.377; P=0.008). Furthermore, expression levels of miR-126 were negatively corrlated with caspase-3 expression levels (r=-0.606; P<0.001) and activity (r=-0.541; P<0.001). There was a negative correlation between miR-21 and levels of TNF-α (r=-0.311; P=0.032) and IL-6 (r=-0.439; P=0.002), as well as caspase-3 expression (r=-0.398; P=0.005) and activity (r=-0.378; P=0.008). However, there miR-126 expression was not correlated with apoptotic rate of T lymphocytes. Altered expression levels of miR-126 and miR-21 reflected the severity of inflammatory response and indicated levels of T lymphocyte apoptosis in septic rats.