miR-155及IFN-γ在新生大鼠急性呼吸窘迫综合征肺损伤模型中的表达

Expression of miR-155 and IFN-γin lung injury model of neonatal rats with acute respiratory distress syndrome

目的采用腹腔内注射脂多糖(lipopolysaccharide,LPS)的方法建立新生大鼠急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)肺损伤模型,检测肺组织中miR-155及IFN-γ的表达情况。方法选取80只新生SD大鼠于生后第7天分配到实验组(LPS组)及对照组(等渗NaCl组),每组40只。LPS溶液以4 mg/kg注射到实验组新生SD大鼠腹腔内,构建新生儿急性呼吸窘迫综合征(neonatal acute respiratory distress syndrome,NARDS)动物模型,等渗NaCl溶液以4 ml/kg注射到对照组新生SD大鼠腹腔内。分别于给药后的3 h、6 h、12 h及24 h进行肺组织标本取材,观察肺组织的表面变化,然后进行肺切片HE染色,观察其病理变化,并进行肺组织损伤评分,最后采用RT-PCR技术和ELISA方法分别测定肺组织内miR-155与IFN-γ的表达情况。结果(1)实验开始后,实验组新生大鼠逐渐呈现出ARDS的临床表现,其肺组织肉眼观察、病理变化及肺组织损伤评分均提示出现NARDS肺损伤表现,表明建模成功。(2)实验组与对照组大鼠肺组织内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及2.43±0.06 vs 0.96±0.02)及IFN-γ(370.79±13.89 vs 273.03±11.44、424.24±10.11 vs 270.70±13.05、466.63±6.57 vs 268.11±7.88及519.13±7.09 vs 272.97±12.54)的表达量(ng/L)相比,差异有统计学意义(P<0.01),且实验组各组进行组间比较,差异有统计学意义(F分别为165.983和408.574,P<0.01)。实验组肺组织内miR-155与IFN-γ的表达量随着时间的延长,逐渐增加,呈上升趋势。结论成功构建NARDS动物模型后,NARDS大鼠肺组织内miR-155及IFN-γ的表达显著增高,且具有时序性,miR-155有望成为诊断NARDS的早期生物标志物。

Objective To study the expression of micro RNA-155(miR-155)and IFN-γin 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-γin 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-γin 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-γin 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.