石菖蒲挥发油对宫内感染所致新生鼠肺损伤的作用

Effects of volatile oil from Acorus tatarinowii on lung injury in neonatal rats induced by intrauterine infection

目的探讨石菖蒲挥发油(volatile oil of Acorus tatarinowii,VOAT)对宫内感染所致新生鼠肺损伤的作用及可能的机制。方法随机选取6只妊娠15 d的SD大鼠作为对照组,子宫颈内注射大肠埃希菌构建宫内感染大鼠模型,并随机分为模型组及VOAT低、中、高剂量组,每组6只,次日给药,其中VOAT低、中、高剂量组大鼠分别灌胃VOAT 5、10、20 g·kg^(−1)·d^(−1),模型组和对照组大鼠灌胃等量生理盐水,连续给药直至分娩。记录各组新生鼠胎龄;测定新生鼠肺指数;用酶联免疫吸附试验(enzymelinked immunosorbent assay,ELISA)测定新生鼠血清白细胞介素(interleukin,IL)-21和IL-6、IL-1β水平;苏木素伊红(hematoxylin-eosin,HE)染色检测新生鼠肺组织病理学变化;实时荧光定量聚合酶链式反应(quantitative real-time polymerase chain reaction,RT-qPCR)检测肺组织中IL-21、IL-21R mRNA的相对表达水平;Western blotting检测肺组织中IL-21、IL-21R、STAT3、p-STAT3蛋白的相对表达量。结果与对照组比较,模型组及VOAT低、中、高剂量组新生鼠胎龄缩短,肺指数降低,血清IL-21、IL-6及IL-1β水平,肺组织中IL-21、IL-21R mRNA的相对表达量及IL-21、IL-21R和p-STAT3蛋白的相对表达量均升高(P<0.05),并出现不同程度的炎性细胞浸润、肺泡壁增厚、肺泡腔变大、结构紊乱等病理学变化;与模型组比较,VOAT低、中、高剂量组新生鼠肺指数升高,血清IL-21、IL-6及IL-1β水平,肺组织中IL-21、IL-21R mRNA的相对表达量及IL-21、IL-21R和p-STAT3蛋白的相对表达量均降低(P<0.05),肺组织病理损伤有不同程度减轻;VOAT对宫内感染所致新生鼠肺损伤的作用效果呈剂量依赖性(P<0.05)。结论VOAT可减轻宫内感染所致新生鼠肺损伤,其作用机制可能与抑制IL-21/STAT3通路激活、降低机体炎症水平有关。

Objective To investigate the effect and mechanism of volatile oil of Acorus tatarinowii(VOAT)on lung injury induced by intrauterine infection in neonatal rats.Methods Six 15-days pregnant SD rats were randomly selected as the control group.The test rats were injected with E.coli into cervix to construct the intrauterine infection model.The modeled rats were randomly divided into model group,low,medium and high dose VOAT groups,with 6 rats in each group.The drugs were administered the next day.The oral doses were 5,10 and 20 g·kg^(−1)·d^(−1) respectively,continuous administration until delivery.The rats in the model group and the control group were only given the same amount of normal saline.The gestational age of newborn rats in each group was recorded.The lung index of newborn rats was measured.The levels of serum interleukin(IL)-21,IL-6 and IL-1βin neonatal rats were detected by enzyme-linked immunosorbent assay(ELISA).The pathological changes of lung tissue were detected by hematoxylin and eosin(HE)staining.The relative expression levels of mRNA of IL-21 and IL-21R in lung tissue were detected by quantitative real-time PCR(RT-qPCR).The relative expression of IL-21,IL-21R,STAT3 and p-STAT3 protein in lung tissue was detected by western blot.Results Compared with the control group,the gestational age of newborn rats was shortened,the lung index was decreased,and the serum IL-21,IL-6 and IL-1β,the relative expression of mRNA of IL-21,IL-21R and the relative expression of IL-21,IL-21R and p-STAT3 protein in lung tissue were increased in the model group and the 3 VOAT administration groups(P<0.05),and there were pathological changes such as inflammatory cell infiltration,thickening of alveolar wall,enlargement of alveolar cavity and structural disorder.Compared with the model group,the lung index was increased,the serum IL-21,IL-6 and IL1β,the relative expression of mRNA of IL-21,IL-21R and the relative expression of IL-21,IL-21R and p-STAT3 protein in lung tissue were all decreased in the low,medium and high dose VOAT groups(P<0.05),and the pathological injury of lung tissue was relieved to varying degrees.The effects of VOAT on neonatal lung injury induced by intrauterine infection were dose-dependent(P<0.05).Conclusion VOAT could alleviate lung injury in neonatal rats caused by intrauterine infection,and its mechanism may be related to inhibiting the activation of IL-21/STAT3 pathway and reducing the level of inflammation.