The Expressions And Biological Significance Of Survivin And Other Apoptosis Associated Genes In Fetal Lungs And In Lung Cancers

Part OnePURPOSE:To explore the expression and significance of Survivin, Caspase-3 and p53, Bax in fetal lungs. METHODS:15 cases of 16-35 week human fetal lung tissues were obtained. The expressions of Survivin, Caspase-3, Bax and p53 were examined by immunohistochemistry in fetal lungs. RESULTS:(1) The expression of Survivin was mainly detected in the epithelial cells of the distal bronchiolar during the pseudoglandular stage and the canalicular stage. During the primitive sac stage, Survivin was expressed in the alveolar cells and was distributed diffusely in the epithelium of the proximal airway on week 35.(2) The expression of Caspase-3 first appeared on week 18, with constant expression sites in the proximal airway surface epithelium. During the primitive sac stage,Caspase-3 was expressed in type II cells, but not expressed in type I cells.(3) Bax and p53 were expressed throughout fetal lung development, prominent in bronchiolar epithelial cells and in alveolar cells. Bax was also expressed in mesenchymal cells. With the development of fetal lung, the positive mesenchymal cells were fewer.CONCLUSIONS:(1) During the early development of fetal lung, Survivin plays an important role in building the bronchiolar tree and in the growth and differentiation of the epithelial cells. Caspase-3 participates in the bronchiolar rebuilding; Bax and p53 participate in refining the fetal lung structural remolding.(2) Survivin cooperated with Caspase-3, p53 in regulating differentiation and maturation of type II cells during the late development of fetal lung.(3) The modulation of expression of Survivin, Caspase-3, Bax and p53 in the apoptotic cascades during these gestational ages suggests that the complex interaction of controlled genes expression according to temporal and spatial laws.