氧化苦参碱对新生鼠高氧性肺损伤的保护作用及机制探讨

Protection of oxymatrine against chronic lung disease induced by hyperoxia in neonatal rats

目的观察高氧致慢性肺疾病(CLD)新生大鼠肺组织转化生长因子β1(TGF?β1)、Smad3、Smad7及结缔组织生长因子(CTGF)水平的动态变化,以探讨氧化苦参碱对高氧性肺损伤的保护作用及机制。方法新生Wistar大鼠128只随机分为空气对照组、氧化苦参碱治疗组、盐水对照组和高氧组,每组各32只,高氧组、盐水对照组和氧化苦参碱治疗组的新生Wistar大鼠(连同母鼠)生后即置于氧舱内,持续吸入高浓度氧(FiO2=0.90)21 d,造成高氧性肺损伤模型;空气对照组吸入空气。氧化苦参碱治疗组于生后当日始每日腹腔注射氧化苦参碱(100 mg/kg),盐水对照组每日腹腔注射等量生理盐水。每组分别于实验开始后第3、7、14、21天随机选取8只麻醉后处死。肺组织采用免疫组化方法检测TGF?β1、Smad3、Smad7及CTGF蛋白的表达并同时观察肺组织形态学变化。结果与空气对照组比较,高氧组、盐水对照组肺组织TGF?β1、Smad3、CTGF蛋白表达在实验后第14天明显升高,第21天达高峰(P<0.05或P<0.01),氧化苦参碱治疗组上述指标与高氧组、盐水对照组比较明显降低(P<0.05或P<0.01),Smad7蛋白表达明显增多(P<0.01)。高氧组、盐水对照组第14天肺组织间质细胞增多,出现纤维化改变。第21天正常肺泡结构消失,肺组织出现严重的纤维化。氧化苦参碱治疗组肺组织纤维化病变明显减轻。结论氧化苦参碱干预抑制了高氧致CLD新生大鼠肺组织TGF?β1、Smad3、CTGF蛋白表达,增加Smad7蛋白表达,减轻了肺纤维化病变,这可能是氧化苦参碱对高氧性肺损伤具有保护作用的机制之一。

Objective To examine the protein expression of TGF-β1,Smad3,Smad7,CTGF in lung of neonatal rats with hyperoxia induced by chronic lung disease（CLD）and investigate the protection mechanism of oxymatrine against CLD.【Methods】 128 neonatal wistar rats were randomly assigned into air group,oxymatrine treated group,normal saline group and model group（n=32）.The air group was exposed to room air（FiO2=0.21）immediately after birth.The other three groups were exposed to hyperoxia（FiO2=0.90）for 21 days to induce lung injury.The oxymatrine treated group received oxymatrine（100 mg/kg）by peritoneal injection after birth.The normal saline group was injected with normal saline instead.At each time interval of 3,7,14 and 21 days after experiment,8 rats of each group were randomly chosen and sacrificed.The protein expression of TGF-β1,Smad3,Smad7,CTGF were measured by immunohistochemistry.The change of lung was observed under a lightmicroscope.Results The protein expression of TGF-β1,Smad3,CTGF increased significantly in the model and normal saline groups on the 14th day and peaked on the 21st day of exposure compared with those of the air group（P0.05 or P0.01）.Oxymatrine treatment reduced significantly the protein expression of TGF-β1,Smad3,CTGF compared with the model and normal saline groups on the 14th and 21st day at the same time.The protein expression of Smad3 was significantly higher than the normal saline and model group（P 0.01）.The histopathologic examination demonstrated broadened lung interstitium and reduced alveolar quantity and lung fibrosis was developed in the model and normal saline groups on the 14th day of exposure.Cap topril treatment obviously alleviated the changes of lung histomorphology.Conclusion Oxymatrine can inhibit the protein expression of TGF-β1,Smad3,CTGF.At the same time,oxymatrine can increase the protein expression of Smad7 and alleviate lung fibrosis in neonatal rats with lung injury/CLD induced by hyperoxia.This may be one of the possible mechanism underlying the protective effect of oxymatrine against lung injury/CLD.