INTRODUCTION: Elastic and collagen fiber deposition increases throughout normal lung development, and this fiber network significantly changes when development of the lung is disturbed. In preterm rats and lambs, prolonged hyperoxic exposure is associated with impaired alveolization and causes significant changes in the deposition and structure of elastic fibers. OBJECTIVES: To evaluate the effects of hyperoxic exposure on elastic and collagen fiber deposition in the lung interstitial matrix and in alveolarization in preterm rabbits. METHODS: After c-section, 28-day preterm New-Zealand-White rabbits were randomized into 2 study groups, according to the oxygen exposure, namely: Room air (oxygen = 21%) or Oxygen (oxygen > 95%). The animals were killed on day 11 and their lungs were analyzed for the alveolar size (Lm), the internal surface area (ISA), the alveoli number, and the density and distribution of collagen and elastic fibers. RESULTS: An increase in the Lm and a decrease in the alveoli number were observed among rabbits that were exposed to hyperoxia with no differences regarding the ISA. No difference in the density of elastic fibers was observed after oxygen exposure, however there were fewer collagen fibers and an evident disorganization of fiber deposition. DISCUSSION: This model reproduces anatomo-pathological injuries representing the arrest of normal alveolar development and lung architecture disorganization by just a prolonged exposition to oxygen. CONCLUSIONS: In the preterm rabbit, prolonged oxygen exposure impaired alveolization and also lowered the proportion of collagen fibers, with an evident fiber network disorganization.

A síndrome de Schinzel-Giedion é uma patologia genética rara de etiologia desconhecida e herança autossômica recessiva. Caracteriza-se pela presença de um fácies grotesco, hipoplasia da porção média da face, hipertricose, múltiplas anomalias esqueléticas, malformações cardíacas e renais.As anomalias craniofaciais desta síndrome podem lembrar o fácies de uma doença metabólica de depósito. O objetivo deste relato foi enfatizar a importância da hidronefrose congênita bilateral no diagnóstico da síndrome de Schinzel-Giedion . Descrevemos o primeiro caso brasileiro de um recém-nascido com fácies típico, hipertricose generalizada, anomalias esqueléticas, cardíacas e hidronefrose bilateral, detectada pela ultrassonografia fetal e, posteriormente, confirmada pelo mesmo método. O estudo cromosômico foi normal. Na literatura, de 35 casos descritos, 31 apresentavam hidronefrose, o que constitui um achado fundamental para o diagnóstico da patologia. Dessa forma, acreditamos que se a síndrome de Schinzel-Giedion fosse indexada como uma das causas de hidronefrose congênita, seu diagnóstico seria facilitado, uma vez que a maioria dos outros achados desta síndrome, com exceção da hidronefrose, é inespecífica e comum a diversas outras síndromes genéticas.

Schinzel-Giedion syndrome is a rare autosomal recessive disorder characterized by coarse facies, midface retraction, hypertrichosis, multiple skeletal anomalies, and cardiac and renal malformations. Craniofacial abnormalities of this syndrome sometimes resemble a storage or metabolic disease. The pathogenesis of the disease remains unknown. The objective of this report was to emphasize the importance of congenital bilateral hydronephrosis for the diagnosis of Schinzel-Giedion syndrome. We describe the first Brazilian case of a newborn with typical facies, generalized hypertrichosis, cardiac and skeletal anomalies, and bilateral hydronephrosis detected during pregnancy and confirmed later by abdominal ultrasonography. Chromosomal constitution was normal. Of the 35 cases already reported in the literature, 31 presented hydronephrosis, which is considered an important clue in diagnosis. If Schinzel-Giedion syndrome were indexed as a cause of congenital hydronephrosis, its identification would be greatly facilitated, since the majority of the other findings in Schinzel-Giedion syndrome are nonspecific and common to many genetic syndromes.