The expression and significance of matrix metalloproteinases-9 and tissue inhibitors of matrix metalloproteinase-1 in serum of infant with severe pneumonia

Abstract

Objective To explore the expression and significance of matrix metalloproteinases-9(MMP-9) and tissue inhibitors of matrix metalloproteinase-1(TIMP-1) in serum at acute phase of severe pneumonia in infants. Methods A total of 45 infants of pneumonia were selected and divided into 20 cases of severe pneumonia group and 25 cases of mild pneumonia group according to the severity of the disease, and all 45 infants were also divided into virus group of 24 cases and non-virus group of 21 cases on the basis of etiology.Additionally, 20 cases of healthy children who accepted the physical examination at the same time were selected as the control group.Serum levels of MMP-9 and TIMP-1 were detected by using ELISA.Tidal breathing lung function was measured in all selected infants. Results Compared with the control group, the serum levels of MMP-9, TIMP-1 and MMP-9/TIMP-1 ratio of the infants with acute pneumonia were significantly higher, the severe pneumonia group were higher than the mild pneumonia group, and the virus group were higher than the non-virus group(P<0.05). The ratio of the time to reach peak tidal expiratory flow to total expiratory time (TPTEF/TE) and the volume to reach peak tidal expiratory flow to total expiratory volume(VPTEF/VE) of pneumonia group in recovery period were significantly lower than those in the control group, severe pneumonia group were lower than those in the mild pneumonia group, and the virus group were lower than those in the non-virus group (all P<0.05). There were no statistically significant about VT/kg among three groups.The serum MMP-9 levels and the MMP-9/TIMP-1 ratio were negatively correlated with TPTEF/TE and VPTEF/VE (r1=-0.459, -0.376; r2=-0.413, -0.327; all P<0.05). Conclusion The serum levels of MMP-9 and the MMP-9/TIMP-1 ratio in the acute phase of infantile pneumonia are correlated with pneumonia severity and pulmonary function injury in recovery period, and the performance is particularly prominent in the viral pneumonia, and can be used as a prognosis monitoring indicator. Key words: Infant; Severe pneumonia; Matrix metalloproteinases-9; Tissue inhibitors of matrix metalloproteinase-1; Lung function,