Expression And Regulatory Function Of Interrelated Polypeptides In Bufo Raddei Fetal Lungs

Based on the histological study of the development of fetal lung in Bufo raddei,the distribution of the epidermal growth factor receptor(EGFR),transforming growth factor-β₁,β₂,β₃(TGF-β₁,TGF-β₂,TGF-β₃)was investigated in.the fetal lung during Bufo raddei tadpole development by the immunohistochemical method,the Image-pro-plus 5.0 professional image analysis was used in quantitatively studying.1.The histological study demonstrated that the development of the lung in larvae of Bufo raddei was studied at different developmental stages from the youngest forms to those entering the metamorphosis,the lung in larvae of Bufo raddei developed in 21 stage in the beginning,it is derivated from the back of the pharynx,next it formed the protuberant lung bud,the lung bud developed slowness during the 22,23,24 stage,while in the 25 stage,it is differentiated the slim lung sac,but the lung was filled with fluid,in the 30 stage,the lung formed the obvious lung sac,the lung was filled with air,in the 39 stage,the lung has approached to the young Bufo raddei fetal lung,the wall of the lung showed attenuation, the lung of the adult Bufo raddei becomed vesicle,the inside wall of the lung there are many net diaphragm and secondary septa so that it is separated to a lot of alveolar sac and pulmonary alveoli,in the inside of the lung surface was covered with a layer of epithelium.2.In the early developmental phase,EGFR localized in epithelium of the reticular septa;37-39 stage,the positive reactions of EGFR were mainly detected in alveolar sac and alveoli epithelium.The localization patterns in the interstitial cells for EGFR were essentially identical;In young toad lung,rich EGFR was mainly localized in alveoli epithelium.The quantitative analysis of EGFR showed:the changes of the EGFR expression level taked on the ascending trend in the development of the lung,at the 30-35 stage,the change was calm,but at 37 stage,the level was reached the peak,after the stage gradually descended,at the 39 stage and the young toad lung,it began rasied.3.TGF-β₁,TGF-β₂,TGF-β₃ were placed in the cytoplasm,the localization patterns of TGF-βin the fetal lung were essentially identical,at the stage 30-35,the TGF-βweak reaction was present in the epithelium of the reticular septa and interstitial cells;at the stage 37-39,the TGF-βimmunoreactivity was reduced in epithelium of the reticular septa,but evident staining was observed in smooth muscle cells and interstitial cells;In young toad lung,the TGF-βwas mainly observed in smooth muscle cells and interstitial cells around blood vessel.The quantitative analysis of TGF-βshowed:the changes of the TGF-βexpression level taked on the intermission trend in the development of the lung,it is showed at the different stages,the expression level of the TGF-βwere different.4.The positive reactions of EGFR,TGF-β₁,TGF-β₂,TGF-β₃ were respectively different stages,which suggests that their functions are changing in individual developmental periods,the EGFR can promote the cells to develop and differentiating,but on the contrary,TGF-βinhibits lung development,They not only stimulate the process of epithelium of the reticular septa,but also modulate epithelium of alveolar sac and differention.The Bufo raddei normal fetal lung development depends on the unity of two opposites.