Expression of miR-155 and IFN-γ in lung injury model of neonatal rats with acute respiratory distress syndrome / 国际儿科学杂志

ABSTRACT

Objective:To study the expression of micro RNA-155(miR-155) and IFN-γ in lung tissue in a neonatal rat model of acute respiratory distress syndrome(ARDS)lung injury by intraperitoneal injection of lipopolysaccharide(LPS).Methods:Eighty neonatal SD rats on the 7th day after birth were assigned to the experimental group(LPS group)and control group(isotonic NaCl group), with 40 rats in each group.LPS solution(4 mg/kg)was injected into the abdominal cavity of neonatal SD rats in the experimental group to establish an animal model of neonatal acute respiratory distress syndrome(NARDS). The control group was established by isotonic NaCl solution(4 ml/kg)in the same way.The lung tissue samples were taken at 3 h, 6 h, 12 h and 24 h after drug administration to observe the surface changes.Then the lung sections were stained with HE to observe the pathological changes and score the lung tissue injury.Finally, the expression levels of miR-155 and IFN-γ in the lung tissue were tested by RT-PCR and ELISA techniques, respectively.Results:(1)At the beginning of the experiment, the neonatal rats in the experimental group gradually showed the clinical manifestations of ARDS, and the macroscopic observation, pathological changes and lung tissue injury scores of the lung tissues suggested the appearance of NARDS lung injury, indicating that the model was successful.(2)The expression levels of miR-155(1.33±0.12 vs 0.95±0.02、1.77±0.17 vs 0.96±0.01、2.18±0.09 vs 0.96±0.02 and 2.43±0.06 vs 0.96±0.02)and IFN-γ(370.79±13.89 vs 273.03±11.44、424.24±10.11vs270.70±13.05、466.63±6.57 vs 268.11±7.88 and 519.13±7.09 vs 272.97±12.54)ng/L in the lung tissue of rats between the experimental group and the control group were significantly different( P<0.01), and the difference was statistically significant among the groups in the experimental group( F values were 165.983 and 408.574, P<0.01). The expression levels of miR-155 and IFN-γ in the lung tissue of the experimental group increased gradually over time and showed an increasing trend. Conclusion:After the successful establishment of NARDS animal model, the expression levels of miR-155 and IFN-γ in the lung tissue of NARDS rats have significantly increased and showed a sequential pattern.MiR-155 is expected to become an early biomarker for the diagnosis of NARDS.