妊娠期肝内胆汁淤积症对胎鼠肺脏形态的影响

Effect of intrahepatic cholestasis on morphology of fetal lungs in pregnant rat

目的 探讨孕鼠发生肝内胆汁淤积症（ICP）时对胎鼠肺脏形态学的影响.方法 将妊娠15 d的20只SD孕鼠随机分为实验组和对照组,每组10只.实验组孕鼠皮下注射17α-乙炔雌二醇和孕酮,连续5 d,成功建立ICP大鼠模型;对照组孕鼠皮下注射精制植物油,连续5 d.分别测定两组孕鼠模型建立前、后血清中丙氨酸氨基转移酶（ALT）、门冬氨酸氨基转移酶（AST）、总胆汁酸（TBA）的水平.于妊娠第21天处死孕鼠,取出孕鼠肝脏组织;处死孕鼠后立即行剖宫取胎术,对取出的胎鼠肺组织和孕鼠肝脏组织进行光镜和电镜的病理学检查.结果 （1）生化指标：模型建立前,实验组孕鼠血中ALT、AST及TBA水平分别为（55±15）U/L、（146±16）U/L及（13±4）μmol/L;对照组分别为（49±12）U/L、（145±20）U/L及（14±4）μmol/L,两组比较,差异无统计学意义（P〉0.05）.模型建立后（于妊娠第21天断颈处死孕鼠）,实验组孕鼠血中ALT、AST及TBA水平分别为（94±12）U/L、（245±26）U/L及（44±16）μmol/L;对照组分别为（59±17）U/L、（163±27）U/L及（17±3）μmol/L,两组比较,差异有统计学意义（P〈0.05）.（2）孕鼠肝脏病理学检查：大体所见,实验组孕鼠肝脏边缘钝厚,色泽灰暗;对照组孕鼠肝脏边缘锐利,色泽红润.光镜下所见,实验组孕鼠中有部分肝细胞肿胀变性,胞质疏松化,肝血窦受压变窄,部分胆管扩张,偶见肝细胞坏死;对照组孕鼠则肝细胞形态及肝小叶结构均正常.（3）胎鼠肺脏组织学检查：实验组胎鼠肺脏色泽灰暗,对照组胎鼠肺脏外观红润.光镜下所见,实验组胎鼠肺组织已发育成熟,但肺间质毛细血管明显扩张、充血,大部分肺泡间隔增宽,肺泡内少量炎性渗出物,灶状肺泡内出血.电镜下所见,肺泡Ⅱ型细胞微绒毛减少,线粒体空泡变性,部分细胞质崩解,板层小体排空增多;对照组为正常肺组织病理表现,肺组织结构清晰,肺泡壁薄,肺泡腔内偶见巨噬细胞,未见炎性细胞浸润.结论 联合应用雌、孕激素能够有效地建立ICP孕鼠模型,且ICP孕鼠的高胆汁酸血症对胎鼠肺组织有明显的毒性损伤作用,导致肺组织发生严重的病理改变.

Objective To investigate the influence of intrahepatic cholestasis of pregnancy （ICP） on the pulmonary morphologic changes of fetal rats.Methods Twenty pregnant SD rats at 15 days of gestations were randomly divided into ICP and control group.Rats in the ICP group were subcutaneously injected with 17-α-ethinylestradiol and progesterone for 5 consecutive days to establish the rat ICP model, and those of the control group received subcutaneous injection of sirasimeyu also for 5 days.The levels of serum alanine aminotransferases （ALT）, aspartate transamlnase （AST）, and total bile salt （TBA） were measured before and after the treatment, respectively.Maternal rats were sacrificed on 21 days of gestations and hysterotomies were performed immediately.Histopathologic changes of mammal rats＇ livers and fetal lungs were observed under light and electron microscopes.Results （1） The maternal serum levels of ALT, AST, and TBA showed no significant difference between the ICP and control group [ALT： （55 ± 15） vs （49 ±12） U/L; AST：（146±16）vs （145±20） U/L; TBA： （13±4） vs （14 ±4） μmol/L, P〉0.05, respectively]before the ICP models were established, but higher levels were shown in the ICP group after [ALT： （94±12） vs （59±17） U/L; AST： （245±26） vs （163±27） U/L; TBA： （44±16） vs （17± 3） μmol/L, P 〈0.05, respectively].（2） The livers of maternal rats＇ in the ICP group were gloomy with blurred margins, however those of the control group were normal.Microscopic observed swollen and degenerated hepatocytes with narrowed hepatic sinusoid, dilated bile duct and necrosis of hepatocytes occasionally in the ICP group, while the morphology of hepatocytes and structures of lobuli hepatis in the control group were normal.（3） The fetal pulmonary tissues in the ICP group were dark, and normal in the control group.Histopathologic examination showed matured fetal pulmonary tissues with dilated and congested interstitial lung capillaries, thickened alveolar septum, mild focal inflammatory exudation and focal hemorrhage in alveolus.Furthermore, reduced microvilli, mitochondrion vacuolization, cytoplasm disintegration and increased lamellar body evacuation were observed in type Ⅱ pneumonocytes in ICP group under light and electron microscopes.While fetal pulmonary tissues of the control group did not show any significant lesions.Conclusions Rat model of ICP can be established with the combination of estrogen and progestin.Hyperbileacidemia in ICP rat may lead to pathological changes in fetal pulmonary tissues.