孕鼠VA缺乏对胎肺VA及其受体和表面活性蛋白基因的影响

Effects of vitamin A deficiency during pregnancy on the lung vitamin A status,its receptor and pulmonary surfactant of fetal rats

目的:探讨孕鼠维生素A(Vitamin A,VA)缺乏对胎肺VA及其受体和表面活性蛋白基因的影响。方法:建立孕期VA正常(Vitamin A normal,VAN)和亚临床缺乏(Marginal vitamin A deficiency,MVAD)动物模型各6只,每组再随机分为地塞米松(Dexamethasone,Dex)组和生理盐水(Normal saline,NS)组,即VAN-Dex组、VAN-NS组、MVAD-Dex组和MVAD-NS组。各组均于孕16、17、18d肌肉注射Dex或NS,于孕19d剖宫取胎鼠,高效液相色谱法(High performance liquid chromatography,HPLC)检测胎鼠肺组织VA含量,逆转录-聚合酶链反应(Reverse transcription-polymerase chain reaction,RT-PCR)方法检测胎鼠肺表面活性蛋白(Pulmonary surfactant,PS)和视黄酸受体(Retinoic acid receptor,RAR)mRNAs的表达,以甘油醛-3-磷酸脱氢酶(Glyc-eraldehyde-3-phosphate dehydrogenase,GAPDH)mRNA扩增产物为内参照,密度扫描作半定量分析。结果:(1)胎鼠肺单位组织VA水平:VAN-Dex组>VAN-NS组,MVAD-Dex组>MVAD-NS组,VAN-Dex组>MVAD-Dex组,VAN-NS组>MVAD-NS组,各组比较差异均有统计学意义(P<0.05)。(2)SP-B和SP-CmRNAs的表达水平:VAN-NS组>MVAD-NS组,MVAD-Dex组>MVAD-NS组,比较差异均有统计学意义(P<0.05);VAN-Dex组>VAN-NS组,VAN-Dex组>MVAD-Dex组,但比较差异均无统计学意义(P>0.05)。(3)RAR-α、RAR-γ和RAR-βmRNAs表达水平:VAN-Dex组>VAN-NS组,MVAD-Dex组>MVAD-NS组,VAN-Dex组<MVAD-Dex组,VAN-NS组<MVAD-NS组,3个基因的表达水平各组比较差异均有统计学意义(P<0.05)。结论:孕期VA缺乏能不同程度的影响胎鼠肺单位组织VA水平、SP-B和SP-CmRNAs以及RAR-α、RAR-γ和RAR-βmRNAs的表达;孕期MVAD时其胎肺成熟度较低,但不影响Dex促胎肺成熟作用的发挥。

Objective： To observe the effects of vitamin A deficiency during pregnancy on the lung vitamin A status, its receptor and pulmonary surfactant of fetal rats. Methods： Prenatal vitamin A normal（VAN）and marginal vitamin A deficiency（ MVAD ）of Sprague-Dawley rat models were employed.There were 6 in each group.Then they were randomly divided into dexamethasone（ Dex ）group and control group respectively.l.e VAN-Dex group,VAN-NS group, MVAD-Dex group and MVAD-NS group.From the gestational days 16 to 18,all the rats were given Dex or Saline by intramuscular injection respectively.On the gestational day 19 ,fetal rats were harvested by cesarean section.The vitamin A concentrations of lung were detected by high-performance liquid chromatography（ HPLC ）, and the levels of pulmonary surfactant（PS）and retinoic acid receptor（RAR）mRNAs were detected by semi-quantitative reverse transcription-polymerase chain reac- tion（RT-PCR）;then the values of PS and RAR mRNAs were compared to glyceraldehyde-3-phosphate dehydrogenase（GAPDH ）mRNA. Results： （1）The vitamin A concentrations of lungs in VAN-NS group were higher than those of MVAD-NS group, higher in VAN-Dex group than in MVAD-Dex group, higher in MVAD-Dex group than in MVAD-NS group, and higher in VAN-Dex group than in VAN-NS group.There were significant differences among the four groups（P〈0.05）; （2）As to the levels of SP-B and SP-C mRNAs,they were higher in VAN-NS group than those in MVAD-NS group, and higher in MVAD-Dex group than in MVAD-NS group.There were significant differences between the two groups（P〈0.05）. The levels in VAN-Dex group were higher than those in VAN-NS group, higher in VAN-Dex group than in MVAD-Dex group, but there were no significant differences（P〉0.05）.（3）With regard to the levels of RAR mRNA, the levels of RAR-α and RAR-γ mRNAs in VAN-Dex group were higher than those in VAN-NS group, higher in MVAD-Dex group than in MVAD-NS group,lower in VAN-Dex group than in MVAD-Dex group,lower in VAN-NS group than in MVAD-NS group.The levels of RAR-β mRNA in the four groups were similar to those of the RAR-α and RAR-γ mRNAs. And There were significant differences（P〈0.05）. Conclusion： The vitamin A concentrations of lungs and the levels of SP-B and SP-C mRNAs, the levels of RAR mRNA, were all influenced by vitamin A deficiency during pregnancy.The fetal lungs of the MVAD＇ s mother is immature, but the effects of Dex will not be affected.