Abstract
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.