Effects Of Antenatal Ambroxol And Dexamethasone On Rat Fetal Lung Morphogenesis

Objective: To compare the effects of antenatal 3-days ambroxoland 3-days dexamethason and 1-day dexamethason on morphogenesisand EGF,TGF-β3,PDGF-A,FGF-2 expression in rat fetal lung.Methods: 12 pregnant rats were divided into four groups randomly:3-days ambroxol group, 3-days dexamethasone group, 1-daysdexamethason group and control group, every group have 3 rats. Ongestational day 19, cesareans were carried out and 6 fetal rat lungs werecollected. The histologic structures of rat lung were observed with lightmicroscope, electronic microscope. The expression of EGF,TGF-β3,PDGF-A,FGF-2 were measured by RT-PCR and immunohistochemistry.Results: 1. Results of light microscope: (1) Compared with controlgroup, fetal rat lung in the three treatment groups had more alveolarnumbers, larger alveolar space, and thinner alveolar septum (P＜0.01). (2)Compared with 1-day dexamethasone group, fetal rat lung in the 3-daysdexamethasone group had more alveolar numbers, larger alveolar space,and thinner alveolar septum (P＜0.01). (3) Compared with ambroxolgroup, fetal rat lung in the two dexamethasone groups had more alveolarnumbers, larger alveolar space, and thinner alveolar septum (P＜0.01). 2. Results of electronic microscope: Under the electronic microscope,lamellar body and cellular organs such as bioblast in endochylema of thethree treatment groups were more common than of the control group,especially in the 3-days dexamethasone group. And lamellar body in thethree treatment groups was more anachromasis and condensed than in thecontrol group. 3. Results of RT-PCR and immunohistochemistry: (1)Compared with control group, the expression level of EGF,TGF-β3,PDGF-A,FGF-2 mRNA and protein in the therapy groups were higher(P＜0.01). (2) Compared with 1-day dexamethasone group and ambroxolgroup, the expression level of EGF,TGF-β3,PDGF-A,FGF-2mRNA and protein in the 3-days dexamethasone group were higher (P＜0.05). (3) Compared with ambroxol group, the expression level of EGF,PDGF-A,FGF-2,TGF-β3 protein and the expression level of EGFPDGF-A,FGF-2 mRNA in the 1-day dexamethasone group were higher(P＜0.01). But there were no significant difference between 1-daydexamethasone group and ambroxol group in the expression of TGF-β3 mRNA (P＞0.05).Conclusion: Ambroxol and dexamethasone both could promote thedevelopment of fetal rat lung and the expression level of EGF,TGF-β3,PDGF-A,FGF-2 mRNA and protein. Multi-dose dexamethasone hadprior effects to single-dose dexamethasone. Multi-dose and single-dosedexamethasone all had prior effects to ambroxol. But consider of many side effects of multi-dose dexamethasone, it suggests that single-dosedexamethasone or ambroxol could be used as a better drug to promotefetal lung maturity.